Instr PropertiesDownload PDFSelected SectionSelected Section and Subsection(s)Entire ManualUpdated2025-01-2819 minute(s) readLabVIEWAPI ReferenceLabVIEW G Instr Properties General Settings:Maximum Queue LengthSpecifies the maximum number of events that can be queued at any time on the given session. This property is read/write until the first time you call VISA Enable Event on a session. Thereafter, it is read only. The default is 50.General Settings:Resource ClassReturns the resource class of the resource string used to open the given session. For example, if the resource string for a given session is COM1 or ASRL1::INSTR, this property returns INSTR, regardless of the class of the I/O control.General Settings:Resource Lock StateReturns the current locking state of the resource associated with the given session. The resource can be unlocked, locked with an exclusive lock, or locked with a shared lock. The default is Unlocked.General Settings:Resource NameReturns the unique identifier for a resource.General Settings:Timeout ValueSpecifies the minimum timeout value, in milliseconds, to use when accessing the device. Note that the actual timeout that VISA returns may be higher than the one requested. The default is 2000.General Settings:User DataSpecifies a data value for the private use of an application. The VISA implementation stores this value in a per-session location, so that user data on other sessions does not affect the user data on this session. VISA does not use this property for any purpose.Interface Information:Interface DescriptionSpecifies human-readable text that describes the given interface. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Interface Information:Interface NumberReturns the board number for the given interface.Interface Information:Interface TypeSpecifies the interface type of the given session.Version Information:Resource Manufacturer IdentificationReturns a value that corresponds to the VXI manufacturer ID of the manufacturer that created the VISA implementation.Version Information:Resource Manufacturer NameReturns the name of the manufacturer that created the implementation. This is not related to the device manufacturer attributes. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Version Information:Version of ImplementationReturns the version of a given implementation. This value is defined by the individual manufacturer and increments with each new revision. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.Version Information:Version of SpecificationReturns the value that uniquely identifies the version of the VISA specification to which the implementation complies. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.FireWire Settings:Destination Upper OffsetSpecifies the upper 16 bits of the 48-bit destination address for a FireWire device. The default is 0xFFFF.FireWire Settings:Lower Chip IDReturns the lower chip ID for a FireWire device.FireWire Settings:Source Upper OffsetSpecifies the upper 16 bits of the 48-bit source address for a FireWire device. The default is 0xFFFF.FireWire Settings:Upper Chip IDReturns the upper chip ID for a FireWire device.FireWire Settings:Vendor IDReturns the vendor ID for a FireWire device.FireWire Settings:Window Upper OffsetSpecifies the upper 16 bits of the 48-bit address for a FireWire device when a window is mapped. The default is 0xFFFF.General Settings:Allow DMA TransfersSpecifies whether I/O accesses should attempt to use DMA (TRUE) or Programmed I/O (FALSE). In some implementations, this property may have global effects even though it is documented as a local property. This behavior affects performance and not functionality. Note: In the Instr class, this property is valid only for GPIB, GPIB-VXI, PXI, and VXI resources.General Settings:Manufacturer IdentificationReturns the ID of the manufacturer that created the device. For VXI resources, this refers to the VXI Manufacturer ID. For PXI/PCI resources, this refers to the Subsystem Vendor ID (SVID) if it is nonzero; otherwise, this refers to the Vendor ID (VID). For USB resources, this refers to the Vendor ID (VID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Manufacturer NameReturns the name of the manufacturer that created the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:Model CodeReturns the device model code assigned by the manufacturer. For VXI resources, this refers to the VXI Model Code. For PXI/PCI resources, if the Subsystem Vendor ID is nonzero, this refers to the Subsystem ID (SSID); otherwise, this refers to the Device ID (DID). For USB resources, this refers to the Product ID (PID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Model NameReturns the model name of the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:SlotReturns the physical slot location of the device. If the slot is unknown, the value returned is -1. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI/PCI resources.General Settings:Trigger IdentifierSpecifies which trigger mechanism to use. In VXI systems, for example, you can choose between software triggers and hardware triggers on a specific trigger line. The default is Software. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI resources.GPIB Settings:Line REN StateReturns the current state of the GPIB REN (Remote ENable) interface line.GPIB Settings:Primary AddressReturns the primary address of the GPIB device used by the given session.GPIB Settings:ReaddressingSpecifies whether to use repeat addressing before each read or write operation. The default is TRUE.GPIB Settings:Secondary AddressReturns the secondary address of the GPIB device used by the given session. If the device does not have a secondary address, the value of this property is 65535 (0xFFFF).GPIB Settings:UnaddressingSpecifies whether to unaddress the device (UNT and UNL) after each read or write operation. The default is FALSE.Interface Information:Interface Number of ParentReturns the board number of the parent device. Note: In the Instr class, this property is valid only for GPIB-VXI resources.Message Based Settings:File Append EnableSpecifies whether VISA Read To File appends or overwrites (truncates) when opening a file. If this property is set to TRUE, VISA Read To File appends when opening a file. If this property is set to FALSE, VISA Read To File overwrites (truncates) when opening a file. The default is FALSE.Message Based Settings:IO ProtocolSpecifies which protocol to use. In VXI, you can choose normal word serial or fast data channel. In GPIB, you can choose normal or high-speed HS-488 transfers. In serial, TCP/IP, or USB, you can choose normal transfers or 488.2-defined strings. In USBTMC, you can choose normal or vendor-specific transfers. The default is Normal.Message Based Settings:Is 488.2 CompliantReturns whether the device is 488.2 compliant.Message Based Settings:Send End EnableSpecifies whether to send an END indicator on the last byte of each write operation. This property is relevant only in VISA Write and related operations. The default is TRUE. On Serial Instr sessions, if this property is set to FALSE, the write transmits the exact contents of the user buffer, without modifying it and without appending anything to the data. If this property is set to TRUE, VISA performs the behavior described in the property End Mode for Writes (ASRL End Out). On GPIB, VXI, GPIB-VXI, TCP/IP Instr, and USB Instr sessions, if this property is set to TRUE, VISA includes the 488.2 defined end of message terminator.Message Based Settings:Suppress End EnableSpecifies whether to terminate a read operation due to an END condition. This property is relevant only in VISA Read and related operations. For all session types that support this property, if this property is set to TRUE, read does not terminate due to an END condition. However, a read may still terminate successfully if the Message Based Settings:Termination Character Enable (TermChar En) property is set to TRUE. Otherwise, read does not terminate until it receives all of the requested data (or an error occurs). The default is FALSE (except for TCP/IP Socket sessions). On Serial Instr sessions, if this property is set to FALSE, VISA performs the behavior described in the Serial Settings:End Mode for Reads (ASRL End In) property. On USB Raw sessions, if this property is set to FALSE, VISA performs the behavior described in the USB Settings:End Mode for Reads (USB End In) property. On TCP/IP Socket sessions, if this property is set to FALSE, if NI-VISA reads some data and then detects a pause in the arrival of data packets, it terminates the read operation. On TCP/IP Socket sessions, the default value for the property is TRUE in NI-VISA. On VXI Instr sessions, if this property is set to FALSE, the END bit terminates read operations.Message Based Settings:Termination CharacterSpecifies a character that, when read, causes a read operation to terminate. The termination character also must be enabled. This default is 0x0A (linefeed).Message Based Settings:Termination Character EnableSpecifies whether a read operation terminates when it receives the termination character. The default is FALSE.PXI/PCI Settings:Allow Write CombiningSpecifies whether the implementation should attempt to combine bus write transfers into a large transfer before bursting over the PCI bus. In some cases you may not be able to change the write combining behavior, so reading this property value may not return the same value that was set.PXI/PCI Settings:Express Settings:Actual Link WidthReturns the PCI Express link width negotiated between the PCI Express host controller and the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:D-Star Bus NumberReturns the differential star bus number of this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:D-Star SetReturns the set of differential star lines connected to this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:Is PCI ExpressReturns whether the device is PXI/PCI or PXI/PCI Express.PXI/PCI Settings:Express Settings:Maximum Link WidthReturns the maximum PCI Express link width of the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:Slot Link WidthReturns the PCI Express link width of the PXI Express peripheral slot in which the device resides. A value of -1 indicates that the device is not a PXI Express device. Common values include 1, 4, and 8.PXI/PCI Settings:PCI Bus NumberReturns the PCI bus number of the PXI/PCI resource.PXI/PCI Settings:PCI Device NumberReturns the PCI device number of the PXI/PCI resource.PXI/PCI Settings:PCI Function NumberReturns the PCI function number of the PXI/PCI resource. For most devices, the function number is 0, but a multifunction device may have a function number up to 7. The meaning of a function number other than 0 is device-specific.PXI/PCI Settings:PCI Resources:BAR0 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR1 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR2 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR3 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR4 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR5 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PXI Chassis NumberReturns the PXI chassis number of this device. A value of -1 means the chassis number is unknown. Other valid values are 0 to 255.PXI/PCI Settings:Slot Local Bus LeftReturns the slot number or special feature connected to the local bus left lines of this device.PXI/PCI Settings:Slot Local Bus RightReturns the slot number or special feature connected to the local bus right lines of this device.PXI/PCI Settings:Slot PathReturns the slot path of this device.PXI/PCI Settings:Star Trigger Bus NumberReturns the star trigger bus number of this device.PXI/PCI Settings:Star Trigger LineReturns the PXI_STAR line connected to this device.PXI/PCI Settings:Trigger Bus NumberReturns the trigger bus number of this device.Register Based Settings:Destination Increment CountSpecifies the number of elements by which to increment the destination address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move Out X operations always read from the same element, essentially treating the destination as a FIFO register.Register Based Settings:Source Increment CountSpecifies the number of elements by which to increment the source address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move In X operations always read from the same element, essentially treating the source as a FIFO register.Register Based Settings:Window AccessReturns whether the current session has a mapped window, and if so, whether the window allows direct pointer dereferences.Register Based Settings:Window Base AddressReturns the base interface address to which this window maps. If the Window Access property is Not Mapped, the value of this property is undefined.Register Based Settings:Window SizeReturns the size of the region mapped to this window. If the Window Access property is Not Mapped, the value of this property is undefined.Serial Settings:Allow TransmitSpecifies whether to allow transmission. If FALSE, the serial port suspends transmission as if an XOFF character has been received. If TRUE, it resumes transmission as if an XON character has been received. If XON/XOFF flow control (software handshaking) is not being used, FALSE is an invalid value. The default is TRUE.Serial Settings:Baud RateSpecifies the baud rate of the given communications port. The rate is represented as an unsigned 32-bit integer so that any baud rate can be used, but the communications port usually requires a commonly used rate such as 300, 1200, 2400, or 9600 baud.Serial Settings:Break LengthSpecifies the duration (in milliseconds) of the break signal asserted when End Mode for Writes (ASRL End Out) is set to Break (3). Valid values include 1-500. The default is 250. If you want to control the assertion state and length of a break signal manually, use the VISA Serial Break VI instead.Serial Settings:Data BitsSpecifies the number of data bits contained in each frame. Valid values include 5-8. The data bits for each frame are located in the low-order bits of every byte stored in memory.Serial Settings:Discard NUL CharactersSpecifies whether to discard each data byte whose value is 0. If this property is TRUE, read operations discard NUL characters. If this property is FALSE, read operations treat NUL characters as normal data characters. For binary transfers, set this property to FALSE. The default is FALSE.Serial Settings:End Mode for ReadsSpecifies the method used to terminate read operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar. If the value is (2) TermChar, then the value of the property Termination Character Enable (TermChar En) is ignored. The default is (2) TermChar.Serial Settings:End Mode for WritesSpecifies the method used to terminate write operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar, (3) Break. The default is (0) None.Serial Settings:Error Replacement CharacterSpecifies the character to use to replace incoming characters that arrive with errors (such as a parity error). The default is 0.Serial Settings:Flow ControlSpecifies the flow control method used for both transmitting and receiving data. Valid values include: (0) Flow None, (1) Flow XON/XOFF, (2) Flow RTS/CTS, (3) Flow XON/XOFF and RTS/CTS, (4) Flow DTR/DSR, (5) Flow XON/XOFF and DTR/DSR. Certain values or combinations of values may not be supported by all serial ports and/or operating systems.Serial Settings:Flow Control XOFF CharacterSpecifies the value of the XOFF character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x13 (Control-S).Serial Settings:Flow Control XON CharacterSpecifies the value of the XON character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x11 (Control-Q).Serial Settings:Is Port ConnectedReturns whether the port is properly connected to another port or device. This property is valid only with serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware.Serial Settings:Modem Line Settings:Break StateSets manual control of the serial port's break state. If asserted, this property suspends character transmission and places the transmission line in a break state until this property is unasserted. If you want VISA to send a break signal after each write operation automatically, use the Break Length (Break Len) and End Mode for Writes (ASRL End Out) properties instead. The default is Unasserted.Serial Settings:Modem Line Settings:Line CTS StateReturns the current state of the Clear To Send (CTS) input signal.Serial Settings:Modem Line Settings:Line DCD StateSpecifies the current state of the Data Carrier Detect (DCD) input signal. This is often used by modems to indicate the detection of a carrier (modem) on the phone line. This signal is also known as Receive Line Signal Detect (RLSD). This property is read only except when the Wire Mode property is set to RS232/DCE, or RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line DSR StateReturns the current state of the Data Set Ready (DSR) input signal.Serial Settings:Modem Line Settings:Line DTR StateAsserts or unasserts the Data Terminal Ready (DTR) output signal manually.Serial Settings:Modem Line Settings:Line RI StateSpecifies the current state of the Ring Indicator (RI) input signal. The RI signal is often used by modems to indicate that the telephone line is ringing. This property is read only except when the Wire Mode property is set to RS232/DCE or to RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line RTS StateAsserts or unasserts the Request To Send (RTS) output signal manually. When the flow control is set to hardware handshaking, it is invalid to change this property.Serial Settings:Number of Bytes at Serial PortReturns the number of bytes currently available at the serial port used by this session.Serial Settings:ParitySpecifies the parity used with every frame that is transmitted or received. Valid values include: (0) Parity None, (1) Parity Odd, (2) Parity Even, (3) Parity Mark, (4) Parity Space. Mark means that the parity bit exists and is always 1. Space means that the parity bit exists and is always 0.Serial Settings:Stop BitsSpecifies the number of stop bits used to indicate the end of a frame. Valid values include: (10) Stop One, (15) Stop One-and-a-Half, (20) Stop Two.Serial Settings:Wire ModeSpecifies the current wire/transceiver mode. For RS485 hardware, this property is valid only with the RS485 serial driver developed by National Instruments. For RS232 hardware, the values RS232/DCE and RS232/Auto are valid only with RS232 serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware. When this feature is not supported, RS232/DTE is the only valid value.TCP/IP Settings:Computer HostnameReturns the host name of the device. If no host name is available, this property returns an empty string.TCP/IP Settings:Dot-Notation AddressReturns the TCPIP address of the device to which the session is connected. This string is formatted in dot notation.TCP/IP Settings:HiSLIP Settings:Encryption EnabledControls and returns communication encryption.TCP/IP Settings:HiSLIP Settings:Maximum Message KBytesSpecifies the HiSLIP maximum message size in kilobytes, where a kilobyte is 1024 bytes.TCP/IP Settings:HiSLIP Settings:Overlap EnabledSpecifies whether the HiSLIP 'overlap' mode is enabled.TCP/IP Settings:HiSLIP Settings:Protocol VersionReturns the negotiated HiSLIP protocol version.TCP/IP Settings:HiSLIP Settings:SASL MechanismReturns a string that indicates the SASL mechanism used to authenticate the client.TCP/IP Settings:Is HiSLIPReturns whether this session is using the HiSLIP protocol to communicate with the device.TCP/IP Settings:Keep-Alive PacketsSpecifies whether to use keep-alive packets on TCP connections. Setting this property to TRUE requests that a TCP/IP provider enable the use of keep-alive packets on TCP connections. After the system detects a dropped connection, VISA returns a lost connection error code on subsequent I/O calls on the session. The time required for the system to detect the dropped connection depends on the system and is not settable. The default is FALSE.TCP/IP Settings:LAN Device NameReturns the LAN device name used by the VXI-11 protocol (for example, inst0) during connection.TCP/IP Settings:No Packet DelaySpecifies whether the Nagle algorithm is enabled. The Nagle algorithm is disabled when this property is TRUE (and vice versa). The Nagle algorithm improves network performance by buffering written data until a full-size packet can be sent. This property is TRUE by default in VISA to verify that writes get flushed immediately.TCP/IP Settings:Server Certificate Expiration DateReturns the expiration date of the server certificate. The form is ASN.1 UTCTime “YYMMDDhhmm[ss]Z.TCP/IP Settings:Server Certificate Is PerpetualIndicates the certificate does not expire.TCP/IP Settings:Server Certificate Issuer NameReturns the name of the CA that signed the certificate in RFC4514 format.TCP/IP Settings:Server Certificate Subject NameReturns the serial number and subject field from the certificate om RFC4514 format.TCP/IP Settings:TLS Cipher SuiteReturns a string that indicates the cipher suite used by TLS.USB Settings:Maximum Interrupt SizeSpecifies the maximum size of data stored by any given USB interrupt. If a USB interrupt contains more data than this size, the data in excess of this size is lost. This property is read/write when the corresponding session is not enabled to receive USB interrupt events. When the session is enabled to receive USB interrupt events, this property is read only.USB Settings:Serial NumberReturns the USB serial number of this device.USB Settings:USB Interface NumberReturns the USB interface number used by the given session.USB Settings:USB ProtocolReturns the USB protocol used by the given session.VXI/VME Settings:Destination Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Data/Privileged (0).VXI/VME Settings:Destination Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Big Endian (0).VXI/VME Settings:Fast Data Channel:Channel ModeSpecifies whether FDC transfers use normal or streaming mode. The default is Normal.VXI/VME Settings:Fast Data Channel:Channel NumberSpecifies which FDC channel to use to transfer data buffers. Valid values include 0-7.VXI/VME Settings:Fast Data Channel:Use Channel PairsSpecifies whether transfers use a pair of FDC channels. If you do not set this property, transfers use only one FDC channel. The default is FALSE.VXI/VME Settings:Immediate ServantReturns whether the VXI device is an immediate servant of the local controller.VXI/VME Settings:Mainframe Logical AddressReturns the lowest logical address in the mainframe in which the device resides.VXI/VME Settings:Source Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Data/Privileged (0).VXI/VME Settings:Source Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Big Endian (0).VXI/VME Settings:Supported VXI Trigger LinesReturns which VXI trigger lines this implementation supports. This property returns a bit vector with bits 0-9 corresponding to TTL0 through ECL1.VXI/VME Settings:VXI Commander Logical AddressReturns the logical address of the commander of the VXI device.VXI/VME Settings:VXI Device ClassReturns the class to which the VXI or VME device belongs.VXI/VME Settings:VXI Logical AddressReturns the logical address of the VXI device.VXI/VME Settings:VXI Memory Address SpaceReturns the VXI address space used by the device.VXI/VME Settings:VXI Memory Base AddressReturns the base address of the device in VXI memory space.VXI/VME Settings:VXI Memory SizeReturns the size of memory requested by the device in VXI memory space.VXI/VME Settings:VXI Trigger DirectionsSpecifies the directions of the mapped TTL triggers lines. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding line is routed out of the frame, and a value of 1 means the line is routed into the frame. Lines must be enabled using VXI/VME Settings:VXI Trigger Lines Enable.VXI/VME Settings:VXI Trigger Lines EnableSpecifies which VXI TLL triggers have mappings. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding trigger line is unmapped, and 1 means a mapping exists. Use VXI/VME Settings:VXI Trigger Directions to set an enabled line's direction.VXI/VME Settings:Window Access PrivilegeSpecifies the address modifier to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Data/Privileged (0).VXI/VME Settings:Window Byte OrderSpecifies the byte order to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Big Endian (0).Parent topic: I/O Session PropertiesWas this information helpful?YesNo
Instr Properties General Settings:Maximum Queue LengthSpecifies the maximum number of events that can be queued at any time on the given session. This property is read/write until the first time you call VISA Enable Event on a session. Thereafter, it is read only. The default is 50.General Settings:Resource ClassReturns the resource class of the resource string used to open the given session. For example, if the resource string for a given session is COM1 or ASRL1::INSTR, this property returns INSTR, regardless of the class of the I/O control.General Settings:Resource Lock StateReturns the current locking state of the resource associated with the given session. The resource can be unlocked, locked with an exclusive lock, or locked with a shared lock. The default is Unlocked.General Settings:Resource NameReturns the unique identifier for a resource.General Settings:Timeout ValueSpecifies the minimum timeout value, in milliseconds, to use when accessing the device. Note that the actual timeout that VISA returns may be higher than the one requested. The default is 2000.General Settings:User DataSpecifies a data value for the private use of an application. The VISA implementation stores this value in a per-session location, so that user data on other sessions does not affect the user data on this session. VISA does not use this property for any purpose.Interface Information:Interface DescriptionSpecifies human-readable text that describes the given interface. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Interface Information:Interface NumberReturns the board number for the given interface.Interface Information:Interface TypeSpecifies the interface type of the given session.Version Information:Resource Manufacturer IdentificationReturns a value that corresponds to the VXI manufacturer ID of the manufacturer that created the VISA implementation.Version Information:Resource Manufacturer NameReturns the name of the manufacturer that created the implementation. This is not related to the device manufacturer attributes. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Version Information:Version of ImplementationReturns the version of a given implementation. This value is defined by the individual manufacturer and increments with each new revision. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.Version Information:Version of SpecificationReturns the value that uniquely identifies the version of the VISA specification to which the implementation complies. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.FireWire Settings:Destination Upper OffsetSpecifies the upper 16 bits of the 48-bit destination address for a FireWire device. The default is 0xFFFF.FireWire Settings:Lower Chip IDReturns the lower chip ID for a FireWire device.FireWire Settings:Source Upper OffsetSpecifies the upper 16 bits of the 48-bit source address for a FireWire device. The default is 0xFFFF.FireWire Settings:Upper Chip IDReturns the upper chip ID for a FireWire device.FireWire Settings:Vendor IDReturns the vendor ID for a FireWire device.FireWire Settings:Window Upper OffsetSpecifies the upper 16 bits of the 48-bit address for a FireWire device when a window is mapped. The default is 0xFFFF.General Settings:Allow DMA TransfersSpecifies whether I/O accesses should attempt to use DMA (TRUE) or Programmed I/O (FALSE). In some implementations, this property may have global effects even though it is documented as a local property. This behavior affects performance and not functionality. Note: In the Instr class, this property is valid only for GPIB, GPIB-VXI, PXI, and VXI resources.General Settings:Manufacturer IdentificationReturns the ID of the manufacturer that created the device. For VXI resources, this refers to the VXI Manufacturer ID. For PXI/PCI resources, this refers to the Subsystem Vendor ID (SVID) if it is nonzero; otherwise, this refers to the Vendor ID (VID). For USB resources, this refers to the Vendor ID (VID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Manufacturer NameReturns the name of the manufacturer that created the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:Model CodeReturns the device model code assigned by the manufacturer. For VXI resources, this refers to the VXI Model Code. For PXI/PCI resources, if the Subsystem Vendor ID is nonzero, this refers to the Subsystem ID (SSID); otherwise, this refers to the Device ID (DID). For USB resources, this refers to the Product ID (PID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Model NameReturns the model name of the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:SlotReturns the physical slot location of the device. If the slot is unknown, the value returned is -1. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI/PCI resources.General Settings:Trigger IdentifierSpecifies which trigger mechanism to use. In VXI systems, for example, you can choose between software triggers and hardware triggers on a specific trigger line. The default is Software. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI resources.GPIB Settings:Line REN StateReturns the current state of the GPIB REN (Remote ENable) interface line.GPIB Settings:Primary AddressReturns the primary address of the GPIB device used by the given session.GPIB Settings:ReaddressingSpecifies whether to use repeat addressing before each read or write operation. The default is TRUE.GPIB Settings:Secondary AddressReturns the secondary address of the GPIB device used by the given session. If the device does not have a secondary address, the value of this property is 65535 (0xFFFF).GPIB Settings:UnaddressingSpecifies whether to unaddress the device (UNT and UNL) after each read or write operation. The default is FALSE.Interface Information:Interface Number of ParentReturns the board number of the parent device. Note: In the Instr class, this property is valid only for GPIB-VXI resources.Message Based Settings:File Append EnableSpecifies whether VISA Read To File appends or overwrites (truncates) when opening a file. If this property is set to TRUE, VISA Read To File appends when opening a file. If this property is set to FALSE, VISA Read To File overwrites (truncates) when opening a file. The default is FALSE.Message Based Settings:IO ProtocolSpecifies which protocol to use. In VXI, you can choose normal word serial or fast data channel. In GPIB, you can choose normal or high-speed HS-488 transfers. In serial, TCP/IP, or USB, you can choose normal transfers or 488.2-defined strings. In USBTMC, you can choose normal or vendor-specific transfers. The default is Normal.Message Based Settings:Is 488.2 CompliantReturns whether the device is 488.2 compliant.Message Based Settings:Send End EnableSpecifies whether to send an END indicator on the last byte of each write operation. This property is relevant only in VISA Write and related operations. The default is TRUE. On Serial Instr sessions, if this property is set to FALSE, the write transmits the exact contents of the user buffer, without modifying it and without appending anything to the data. If this property is set to TRUE, VISA performs the behavior described in the property End Mode for Writes (ASRL End Out). On GPIB, VXI, GPIB-VXI, TCP/IP Instr, and USB Instr sessions, if this property is set to TRUE, VISA includes the 488.2 defined end of message terminator.Message Based Settings:Suppress End EnableSpecifies whether to terminate a read operation due to an END condition. This property is relevant only in VISA Read and related operations. For all session types that support this property, if this property is set to TRUE, read does not terminate due to an END condition. However, a read may still terminate successfully if the Message Based Settings:Termination Character Enable (TermChar En) property is set to TRUE. Otherwise, read does not terminate until it receives all of the requested data (or an error occurs). The default is FALSE (except for TCP/IP Socket sessions). On Serial Instr sessions, if this property is set to FALSE, VISA performs the behavior described in the Serial Settings:End Mode for Reads (ASRL End In) property. On USB Raw sessions, if this property is set to FALSE, VISA performs the behavior described in the USB Settings:End Mode for Reads (USB End In) property. On TCP/IP Socket sessions, if this property is set to FALSE, if NI-VISA reads some data and then detects a pause in the arrival of data packets, it terminates the read operation. On TCP/IP Socket sessions, the default value for the property is TRUE in NI-VISA. On VXI Instr sessions, if this property is set to FALSE, the END bit terminates read operations.Message Based Settings:Termination CharacterSpecifies a character that, when read, causes a read operation to terminate. The termination character also must be enabled. This default is 0x0A (linefeed).Message Based Settings:Termination Character EnableSpecifies whether a read operation terminates when it receives the termination character. The default is FALSE.PXI/PCI Settings:Allow Write CombiningSpecifies whether the implementation should attempt to combine bus write transfers into a large transfer before bursting over the PCI bus. In some cases you may not be able to change the write combining behavior, so reading this property value may not return the same value that was set.PXI/PCI Settings:Express Settings:Actual Link WidthReturns the PCI Express link width negotiated between the PCI Express host controller and the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:D-Star Bus NumberReturns the differential star bus number of this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:D-Star SetReturns the set of differential star lines connected to this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:Is PCI ExpressReturns whether the device is PXI/PCI or PXI/PCI Express.PXI/PCI Settings:Express Settings:Maximum Link WidthReturns the maximum PCI Express link width of the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:Slot Link WidthReturns the PCI Express link width of the PXI Express peripheral slot in which the device resides. A value of -1 indicates that the device is not a PXI Express device. Common values include 1, 4, and 8.PXI/PCI Settings:PCI Bus NumberReturns the PCI bus number of the PXI/PCI resource.PXI/PCI Settings:PCI Device NumberReturns the PCI device number of the PXI/PCI resource.PXI/PCI Settings:PCI Function NumberReturns the PCI function number of the PXI/PCI resource. For most devices, the function number is 0, but a multifunction device may have a function number up to 7. The meaning of a function number other than 0 is device-specific.PXI/PCI Settings:PCI Resources:BAR0 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR1 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR2 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR3 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR4 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR5 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PXI Chassis NumberReturns the PXI chassis number of this device. A value of -1 means the chassis number is unknown. Other valid values are 0 to 255.PXI/PCI Settings:Slot Local Bus LeftReturns the slot number or special feature connected to the local bus left lines of this device.PXI/PCI Settings:Slot Local Bus RightReturns the slot number or special feature connected to the local bus right lines of this device.PXI/PCI Settings:Slot PathReturns the slot path of this device.PXI/PCI Settings:Star Trigger Bus NumberReturns the star trigger bus number of this device.PXI/PCI Settings:Star Trigger LineReturns the PXI_STAR line connected to this device.PXI/PCI Settings:Trigger Bus NumberReturns the trigger bus number of this device.Register Based Settings:Destination Increment CountSpecifies the number of elements by which to increment the destination address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move Out X operations always read from the same element, essentially treating the destination as a FIFO register.Register Based Settings:Source Increment CountSpecifies the number of elements by which to increment the source address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move In X operations always read from the same element, essentially treating the source as a FIFO register.Register Based Settings:Window AccessReturns whether the current session has a mapped window, and if so, whether the window allows direct pointer dereferences.Register Based Settings:Window Base AddressReturns the base interface address to which this window maps. If the Window Access property is Not Mapped, the value of this property is undefined.Register Based Settings:Window SizeReturns the size of the region mapped to this window. If the Window Access property is Not Mapped, the value of this property is undefined.Serial Settings:Allow TransmitSpecifies whether to allow transmission. If FALSE, the serial port suspends transmission as if an XOFF character has been received. If TRUE, it resumes transmission as if an XON character has been received. If XON/XOFF flow control (software handshaking) is not being used, FALSE is an invalid value. The default is TRUE.Serial Settings:Baud RateSpecifies the baud rate of the given communications port. The rate is represented as an unsigned 32-bit integer so that any baud rate can be used, but the communications port usually requires a commonly used rate such as 300, 1200, 2400, or 9600 baud.Serial Settings:Break LengthSpecifies the duration (in milliseconds) of the break signal asserted when End Mode for Writes (ASRL End Out) is set to Break (3). Valid values include 1-500. The default is 250. If you want to control the assertion state and length of a break signal manually, use the VISA Serial Break VI instead.Serial Settings:Data BitsSpecifies the number of data bits contained in each frame. Valid values include 5-8. The data bits for each frame are located in the low-order bits of every byte stored in memory.Serial Settings:Discard NUL CharactersSpecifies whether to discard each data byte whose value is 0. If this property is TRUE, read operations discard NUL characters. If this property is FALSE, read operations treat NUL characters as normal data characters. For binary transfers, set this property to FALSE. The default is FALSE.Serial Settings:End Mode for ReadsSpecifies the method used to terminate read operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar. If the value is (2) TermChar, then the value of the property Termination Character Enable (TermChar En) is ignored. The default is (2) TermChar.Serial Settings:End Mode for WritesSpecifies the method used to terminate write operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar, (3) Break. The default is (0) None.Serial Settings:Error Replacement CharacterSpecifies the character to use to replace incoming characters that arrive with errors (such as a parity error). The default is 0.Serial Settings:Flow ControlSpecifies the flow control method used for both transmitting and receiving data. Valid values include: (0) Flow None, (1) Flow XON/XOFF, (2) Flow RTS/CTS, (3) Flow XON/XOFF and RTS/CTS, (4) Flow DTR/DSR, (5) Flow XON/XOFF and DTR/DSR. Certain values or combinations of values may not be supported by all serial ports and/or operating systems.Serial Settings:Flow Control XOFF CharacterSpecifies the value of the XOFF character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x13 (Control-S).Serial Settings:Flow Control XON CharacterSpecifies the value of the XON character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x11 (Control-Q).Serial Settings:Is Port ConnectedReturns whether the port is properly connected to another port or device. This property is valid only with serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware.Serial Settings:Modem Line Settings:Break StateSets manual control of the serial port's break state. If asserted, this property suspends character transmission and places the transmission line in a break state until this property is unasserted. If you want VISA to send a break signal after each write operation automatically, use the Break Length (Break Len) and End Mode for Writes (ASRL End Out) properties instead. The default is Unasserted.Serial Settings:Modem Line Settings:Line CTS StateReturns the current state of the Clear To Send (CTS) input signal.Serial Settings:Modem Line Settings:Line DCD StateSpecifies the current state of the Data Carrier Detect (DCD) input signal. This is often used by modems to indicate the detection of a carrier (modem) on the phone line. This signal is also known as Receive Line Signal Detect (RLSD). This property is read only except when the Wire Mode property is set to RS232/DCE, or RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line DSR StateReturns the current state of the Data Set Ready (DSR) input signal.Serial Settings:Modem Line Settings:Line DTR StateAsserts or unasserts the Data Terminal Ready (DTR) output signal manually.Serial Settings:Modem Line Settings:Line RI StateSpecifies the current state of the Ring Indicator (RI) input signal. The RI signal is often used by modems to indicate that the telephone line is ringing. This property is read only except when the Wire Mode property is set to RS232/DCE or to RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line RTS StateAsserts or unasserts the Request To Send (RTS) output signal manually. When the flow control is set to hardware handshaking, it is invalid to change this property.Serial Settings:Number of Bytes at Serial PortReturns the number of bytes currently available at the serial port used by this session.Serial Settings:ParitySpecifies the parity used with every frame that is transmitted or received. Valid values include: (0) Parity None, (1) Parity Odd, (2) Parity Even, (3) Parity Mark, (4) Parity Space. Mark means that the parity bit exists and is always 1. Space means that the parity bit exists and is always 0.Serial Settings:Stop BitsSpecifies the number of stop bits used to indicate the end of a frame. Valid values include: (10) Stop One, (15) Stop One-and-a-Half, (20) Stop Two.Serial Settings:Wire ModeSpecifies the current wire/transceiver mode. For RS485 hardware, this property is valid only with the RS485 serial driver developed by National Instruments. For RS232 hardware, the values RS232/DCE and RS232/Auto are valid only with RS232 serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware. When this feature is not supported, RS232/DTE is the only valid value.TCP/IP Settings:Computer HostnameReturns the host name of the device. If no host name is available, this property returns an empty string.TCP/IP Settings:Dot-Notation AddressReturns the TCPIP address of the device to which the session is connected. This string is formatted in dot notation.TCP/IP Settings:HiSLIP Settings:Encryption EnabledControls and returns communication encryption.TCP/IP Settings:HiSLIP Settings:Maximum Message KBytesSpecifies the HiSLIP maximum message size in kilobytes, where a kilobyte is 1024 bytes.TCP/IP Settings:HiSLIP Settings:Overlap EnabledSpecifies whether the HiSLIP 'overlap' mode is enabled.TCP/IP Settings:HiSLIP Settings:Protocol VersionReturns the negotiated HiSLIP protocol version.TCP/IP Settings:HiSLIP Settings:SASL MechanismReturns a string that indicates the SASL mechanism used to authenticate the client.TCP/IP Settings:Is HiSLIPReturns whether this session is using the HiSLIP protocol to communicate with the device.TCP/IP Settings:Keep-Alive PacketsSpecifies whether to use keep-alive packets on TCP connections. Setting this property to TRUE requests that a TCP/IP provider enable the use of keep-alive packets on TCP connections. After the system detects a dropped connection, VISA returns a lost connection error code on subsequent I/O calls on the session. The time required for the system to detect the dropped connection depends on the system and is not settable. The default is FALSE.TCP/IP Settings:LAN Device NameReturns the LAN device name used by the VXI-11 protocol (for example, inst0) during connection.TCP/IP Settings:No Packet DelaySpecifies whether the Nagle algorithm is enabled. The Nagle algorithm is disabled when this property is TRUE (and vice versa). The Nagle algorithm improves network performance by buffering written data until a full-size packet can be sent. This property is TRUE by default in VISA to verify that writes get flushed immediately.TCP/IP Settings:Server Certificate Expiration DateReturns the expiration date of the server certificate. The form is ASN.1 UTCTime “YYMMDDhhmm[ss]Z.TCP/IP Settings:Server Certificate Is PerpetualIndicates the certificate does not expire.TCP/IP Settings:Server Certificate Issuer NameReturns the name of the CA that signed the certificate in RFC4514 format.TCP/IP Settings:Server Certificate Subject NameReturns the serial number and subject field from the certificate om RFC4514 format.TCP/IP Settings:TLS Cipher SuiteReturns a string that indicates the cipher suite used by TLS.USB Settings:Maximum Interrupt SizeSpecifies the maximum size of data stored by any given USB interrupt. If a USB interrupt contains more data than this size, the data in excess of this size is lost. This property is read/write when the corresponding session is not enabled to receive USB interrupt events. When the session is enabled to receive USB interrupt events, this property is read only.USB Settings:Serial NumberReturns the USB serial number of this device.USB Settings:USB Interface NumberReturns the USB interface number used by the given session.USB Settings:USB ProtocolReturns the USB protocol used by the given session.VXI/VME Settings:Destination Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Data/Privileged (0).VXI/VME Settings:Destination Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Big Endian (0).VXI/VME Settings:Fast Data Channel:Channel ModeSpecifies whether FDC transfers use normal or streaming mode. The default is Normal.VXI/VME Settings:Fast Data Channel:Channel NumberSpecifies which FDC channel to use to transfer data buffers. Valid values include 0-7.VXI/VME Settings:Fast Data Channel:Use Channel PairsSpecifies whether transfers use a pair of FDC channels. If you do not set this property, transfers use only one FDC channel. The default is FALSE.VXI/VME Settings:Immediate ServantReturns whether the VXI device is an immediate servant of the local controller.VXI/VME Settings:Mainframe Logical AddressReturns the lowest logical address in the mainframe in which the device resides.VXI/VME Settings:Source Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Data/Privileged (0).VXI/VME Settings:Source Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Big Endian (0).VXI/VME Settings:Supported VXI Trigger LinesReturns which VXI trigger lines this implementation supports. This property returns a bit vector with bits 0-9 corresponding to TTL0 through ECL1.VXI/VME Settings:VXI Commander Logical AddressReturns the logical address of the commander of the VXI device.VXI/VME Settings:VXI Device ClassReturns the class to which the VXI or VME device belongs.VXI/VME Settings:VXI Logical AddressReturns the logical address of the VXI device.VXI/VME Settings:VXI Memory Address SpaceReturns the VXI address space used by the device.VXI/VME Settings:VXI Memory Base AddressReturns the base address of the device in VXI memory space.VXI/VME Settings:VXI Memory SizeReturns the size of memory requested by the device in VXI memory space.VXI/VME Settings:VXI Trigger DirectionsSpecifies the directions of the mapped TTL triggers lines. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding line is routed out of the frame, and a value of 1 means the line is routed into the frame. Lines must be enabled using VXI/VME Settings:VXI Trigger Lines Enable.VXI/VME Settings:VXI Trigger Lines EnableSpecifies which VXI TLL triggers have mappings. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding trigger line is unmapped, and 1 means a mapping exists. Use VXI/VME Settings:VXI Trigger Directions to set an enabled line's direction.VXI/VME Settings:Window Access PrivilegeSpecifies the address modifier to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Data/Privileged (0).VXI/VME Settings:Window Byte OrderSpecifies the byte order to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Big Endian (0).Parent topic: I/O Session Properties
Instr Properties General Settings:Maximum Queue LengthSpecifies the maximum number of events that can be queued at any time on the given session. This property is read/write until the first time you call VISA Enable Event on a session. Thereafter, it is read only. The default is 50.General Settings:Resource ClassReturns the resource class of the resource string used to open the given session. For example, if the resource string for a given session is COM1 or ASRL1::INSTR, this property returns INSTR, regardless of the class of the I/O control.General Settings:Resource Lock StateReturns the current locking state of the resource associated with the given session. The resource can be unlocked, locked with an exclusive lock, or locked with a shared lock. The default is Unlocked.General Settings:Resource NameReturns the unique identifier for a resource.General Settings:Timeout ValueSpecifies the minimum timeout value, in milliseconds, to use when accessing the device. Note that the actual timeout that VISA returns may be higher than the one requested. The default is 2000.General Settings:User DataSpecifies a data value for the private use of an application. The VISA implementation stores this value in a per-session location, so that user data on other sessions does not affect the user data on this session. VISA does not use this property for any purpose.Interface Information:Interface DescriptionSpecifies human-readable text that describes the given interface. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Interface Information:Interface NumberReturns the board number for the given interface.Interface Information:Interface TypeSpecifies the interface type of the given session.Version Information:Resource Manufacturer IdentificationReturns a value that corresponds to the VXI manufacturer ID of the manufacturer that created the VISA implementation.Version Information:Resource Manufacturer NameReturns the name of the manufacturer that created the implementation. This is not related to the device manufacturer attributes. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions.Version Information:Version of ImplementationReturns the version of a given implementation. This value is defined by the individual manufacturer and increments with each new revision. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.Version Information:Version of SpecificationReturns the value that uniquely identifies the version of the VISA specification to which the implementation complies. The format of the value has the upper 12 bits as the major number of the version, the next lower 12 bits as the minor number of the version, and the lowest 8 bits as the sub-minor number of the version.FireWire Settings:Destination Upper OffsetSpecifies the upper 16 bits of the 48-bit destination address for a FireWire device. The default is 0xFFFF.FireWire Settings:Lower Chip IDReturns the lower chip ID for a FireWire device.FireWire Settings:Source Upper OffsetSpecifies the upper 16 bits of the 48-bit source address for a FireWire device. The default is 0xFFFF.FireWire Settings:Upper Chip IDReturns the upper chip ID for a FireWire device.FireWire Settings:Vendor IDReturns the vendor ID for a FireWire device.FireWire Settings:Window Upper OffsetSpecifies the upper 16 bits of the 48-bit address for a FireWire device when a window is mapped. The default is 0xFFFF.General Settings:Allow DMA TransfersSpecifies whether I/O accesses should attempt to use DMA (TRUE) or Programmed I/O (FALSE). In some implementations, this property may have global effects even though it is documented as a local property. This behavior affects performance and not functionality. Note: In the Instr class, this property is valid only for GPIB, GPIB-VXI, PXI, and VXI resources.General Settings:Manufacturer IdentificationReturns the ID of the manufacturer that created the device. For VXI resources, this refers to the VXI Manufacturer ID. For PXI/PCI resources, this refers to the Subsystem Vendor ID (SVID) if it is nonzero; otherwise, this refers to the Vendor ID (VID). For USB resources, this refers to the Vendor ID (VID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Manufacturer NameReturns the name of the manufacturer that created the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:Model CodeReturns the device model code assigned by the manufacturer. For VXI resources, this refers to the VXI Model Code. For PXI/PCI resources, if the Subsystem Vendor ID is nonzero, this refers to the Subsystem ID (SSID); otherwise, this refers to the Device ID (DID). For USB resources, this refers to the Product ID (PID). Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, and USB resources.General Settings:Model NameReturns the model name of the device. Note: Use the value of this property for display purposes only and not for programmatic decisions. The value can change between VISA implementations and/or revisions. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, PXI/PCI, FireWire, and USB resources.General Settings:SlotReturns the physical slot location of the device. If the slot is unknown, the value returned is -1. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI/PCI resources.General Settings:Trigger IdentifierSpecifies which trigger mechanism to use. In VXI systems, for example, you can choose between software triggers and hardware triggers on a specific trigger line. The default is Software. Note: In the Instr class, this property is valid only for GPIB-VXI, VXI, and PXI resources.GPIB Settings:Line REN StateReturns the current state of the GPIB REN (Remote ENable) interface line.GPIB Settings:Primary AddressReturns the primary address of the GPIB device used by the given session.GPIB Settings:ReaddressingSpecifies whether to use repeat addressing before each read or write operation. The default is TRUE.GPIB Settings:Secondary AddressReturns the secondary address of the GPIB device used by the given session. If the device does not have a secondary address, the value of this property is 65535 (0xFFFF).GPIB Settings:UnaddressingSpecifies whether to unaddress the device (UNT and UNL) after each read or write operation. The default is FALSE.Interface Information:Interface Number of ParentReturns the board number of the parent device. Note: In the Instr class, this property is valid only for GPIB-VXI resources.Message Based Settings:File Append EnableSpecifies whether VISA Read To File appends or overwrites (truncates) when opening a file. If this property is set to TRUE, VISA Read To File appends when opening a file. If this property is set to FALSE, VISA Read To File overwrites (truncates) when opening a file. The default is FALSE.Message Based Settings:IO ProtocolSpecifies which protocol to use. In VXI, you can choose normal word serial or fast data channel. In GPIB, you can choose normal or high-speed HS-488 transfers. In serial, TCP/IP, or USB, you can choose normal transfers or 488.2-defined strings. In USBTMC, you can choose normal or vendor-specific transfers. The default is Normal.Message Based Settings:Is 488.2 CompliantReturns whether the device is 488.2 compliant.Message Based Settings:Send End EnableSpecifies whether to send an END indicator on the last byte of each write operation. This property is relevant only in VISA Write and related operations. The default is TRUE. On Serial Instr sessions, if this property is set to FALSE, the write transmits the exact contents of the user buffer, without modifying it and without appending anything to the data. If this property is set to TRUE, VISA performs the behavior described in the property End Mode for Writes (ASRL End Out). On GPIB, VXI, GPIB-VXI, TCP/IP Instr, and USB Instr sessions, if this property is set to TRUE, VISA includes the 488.2 defined end of message terminator.Message Based Settings:Suppress End EnableSpecifies whether to terminate a read operation due to an END condition. This property is relevant only in VISA Read and related operations. For all session types that support this property, if this property is set to TRUE, read does not terminate due to an END condition. However, a read may still terminate successfully if the Message Based Settings:Termination Character Enable (TermChar En) property is set to TRUE. Otherwise, read does not terminate until it receives all of the requested data (or an error occurs). The default is FALSE (except for TCP/IP Socket sessions). On Serial Instr sessions, if this property is set to FALSE, VISA performs the behavior described in the Serial Settings:End Mode for Reads (ASRL End In) property. On USB Raw sessions, if this property is set to FALSE, VISA performs the behavior described in the USB Settings:End Mode for Reads (USB End In) property. On TCP/IP Socket sessions, if this property is set to FALSE, if NI-VISA reads some data and then detects a pause in the arrival of data packets, it terminates the read operation. On TCP/IP Socket sessions, the default value for the property is TRUE in NI-VISA. On VXI Instr sessions, if this property is set to FALSE, the END bit terminates read operations.Message Based Settings:Termination CharacterSpecifies a character that, when read, causes a read operation to terminate. The termination character also must be enabled. This default is 0x0A (linefeed).Message Based Settings:Termination Character EnableSpecifies whether a read operation terminates when it receives the termination character. The default is FALSE.PXI/PCI Settings:Allow Write CombiningSpecifies whether the implementation should attempt to combine bus write transfers into a large transfer before bursting over the PCI bus. In some cases you may not be able to change the write combining behavior, so reading this property value may not return the same value that was set.PXI/PCI Settings:Express Settings:Actual Link WidthReturns the PCI Express link width negotiated between the PCI Express host controller and the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:D-Star Bus NumberReturns the differential star bus number of this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:D-Star SetReturns the set of differential star lines connected to this device. A value of -1 means that the chassis is unidentified or does not have a timing slot.PXI/PCI Settings:Express Settings:Is PCI ExpressReturns whether the device is PXI/PCI or PXI/PCI Express.PXI/PCI Settings:Express Settings:Maximum Link WidthReturns the maximum PCI Express link width of the device. A value of -1 indicates that the device is not a PXI/PCI Express device. Common values include 1, 2, 4, 8, and 16.PXI/PCI Settings:Express Settings:Slot Link WidthReturns the PCI Express link width of the PXI Express peripheral slot in which the device resides. A value of -1 indicates that the device is not a PXI Express device. Common values include 1, 4, and 8.PXI/PCI Settings:PCI Bus NumberReturns the PCI bus number of the PXI/PCI resource.PXI/PCI Settings:PCI Device NumberReturns the PCI device number of the PXI/PCI resource.PXI/PCI Settings:PCI Function NumberReturns the PCI function number of the PXI/PCI resource. For most devices, the function number is 0, but a multifunction device may have a function number up to 7. The meaning of a function number other than 0 is device-specific.PXI/PCI Settings:PCI Resources:BAR0 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR0 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR1 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR1 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR2 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR2 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR3 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR3 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR4 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR4 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PCI Resources:BAR5 Address BaseReturns the system-assigned base this device uses in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address SizeReturns the requested address size of this device in the given space. If the device does not request addresses in this space, the value of this property is undefined.PXI/PCI Settings:PCI Resources:BAR5 Address TypeReturns what type of address requirements (memory or I/O) the device has for this Base Address Register. If the device does not request addresses in this space, this property returns None (0).PXI/PCI Settings:PXI Chassis NumberReturns the PXI chassis number of this device. A value of -1 means the chassis number is unknown. Other valid values are 0 to 255.PXI/PCI Settings:Slot Local Bus LeftReturns the slot number or special feature connected to the local bus left lines of this device.PXI/PCI Settings:Slot Local Bus RightReturns the slot number or special feature connected to the local bus right lines of this device.PXI/PCI Settings:Slot PathReturns the slot path of this device.PXI/PCI Settings:Star Trigger Bus NumberReturns the star trigger bus number of this device.PXI/PCI Settings:Star Trigger LineReturns the PXI_STAR line connected to this device.PXI/PCI Settings:Trigger Bus NumberReturns the trigger bus number of this device.Register Based Settings:Destination Increment CountSpecifies the number of elements by which to increment the destination address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move Out X operations always read from the same element, essentially treating the destination as a FIFO register.Register Based Settings:Source Increment CountSpecifies the number of elements by which to increment the source address on block move operations. Valid values include 0 and 1. The default is 1. If this property is set to 0, VISA Move In X operations always read from the same element, essentially treating the source as a FIFO register.Register Based Settings:Window AccessReturns whether the current session has a mapped window, and if so, whether the window allows direct pointer dereferences.Register Based Settings:Window Base AddressReturns the base interface address to which this window maps. If the Window Access property is Not Mapped, the value of this property is undefined.Register Based Settings:Window SizeReturns the size of the region mapped to this window. If the Window Access property is Not Mapped, the value of this property is undefined.Serial Settings:Allow TransmitSpecifies whether to allow transmission. If FALSE, the serial port suspends transmission as if an XOFF character has been received. If TRUE, it resumes transmission as if an XON character has been received. If XON/XOFF flow control (software handshaking) is not being used, FALSE is an invalid value. The default is TRUE.Serial Settings:Baud RateSpecifies the baud rate of the given communications port. The rate is represented as an unsigned 32-bit integer so that any baud rate can be used, but the communications port usually requires a commonly used rate such as 300, 1200, 2400, or 9600 baud.Serial Settings:Break LengthSpecifies the duration (in milliseconds) of the break signal asserted when End Mode for Writes (ASRL End Out) is set to Break (3). Valid values include 1-500. The default is 250. If you want to control the assertion state and length of a break signal manually, use the VISA Serial Break VI instead.Serial Settings:Data BitsSpecifies the number of data bits contained in each frame. Valid values include 5-8. The data bits for each frame are located in the low-order bits of every byte stored in memory.Serial Settings:Discard NUL CharactersSpecifies whether to discard each data byte whose value is 0. If this property is TRUE, read operations discard NUL characters. If this property is FALSE, read operations treat NUL characters as normal data characters. For binary transfers, set this property to FALSE. The default is FALSE.Serial Settings:End Mode for ReadsSpecifies the method used to terminate read operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar. If the value is (2) TermChar, then the value of the property Termination Character Enable (TermChar En) is ignored. The default is (2) TermChar.Serial Settings:End Mode for WritesSpecifies the method used to terminate write operations. Valid values include: (0) None, (1) Last Bit, (2) TermChar, (3) Break. The default is (0) None.Serial Settings:Error Replacement CharacterSpecifies the character to use to replace incoming characters that arrive with errors (such as a parity error). The default is 0.Serial Settings:Flow ControlSpecifies the flow control method used for both transmitting and receiving data. Valid values include: (0) Flow None, (1) Flow XON/XOFF, (2) Flow RTS/CTS, (3) Flow XON/XOFF and RTS/CTS, (4) Flow DTR/DSR, (5) Flow XON/XOFF and DTR/DSR. Certain values or combinations of values may not be supported by all serial ports and/or operating systems.Serial Settings:Flow Control XOFF CharacterSpecifies the value of the XOFF character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x13 (Control-S).Serial Settings:Flow Control XON CharacterSpecifies the value of the XON character used for XON/XOFF flow control (both directions). If XON/XOFF flow control (software handshaking) is not being used, the value of this property is ignored. The default is 0x11 (Control-Q).Serial Settings:Is Port ConnectedReturns whether the port is properly connected to another port or device. This property is valid only with serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware.Serial Settings:Modem Line Settings:Break StateSets manual control of the serial port's break state. If asserted, this property suspends character transmission and places the transmission line in a break state until this property is unasserted. If you want VISA to send a break signal after each write operation automatically, use the Break Length (Break Len) and End Mode for Writes (ASRL End Out) properties instead. The default is Unasserted.Serial Settings:Modem Line Settings:Line CTS StateReturns the current state of the Clear To Send (CTS) input signal.Serial Settings:Modem Line Settings:Line DCD StateSpecifies the current state of the Data Carrier Detect (DCD) input signal. This is often used by modems to indicate the detection of a carrier (modem) on the phone line. This signal is also known as Receive Line Signal Detect (RLSD). This property is read only except when the Wire Mode property is set to RS232/DCE, or RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line DSR StateReturns the current state of the Data Set Ready (DSR) input signal.Serial Settings:Modem Line Settings:Line DTR StateAsserts or unasserts the Data Terminal Ready (DTR) output signal manually.Serial Settings:Modem Line Settings:Line RI StateSpecifies the current state of the Ring Indicator (RI) input signal. The RI signal is often used by modems to indicate that the telephone line is ringing. This property is read only except when the Wire Mode property is set to RS232/DCE or to RS232/Auto with the hardware currently in the DCE state.Serial Settings:Modem Line Settings:Line RTS StateAsserts or unasserts the Request To Send (RTS) output signal manually. When the flow control is set to hardware handshaking, it is invalid to change this property.Serial Settings:Number of Bytes at Serial PortReturns the number of bytes currently available at the serial port used by this session.Serial Settings:ParitySpecifies the parity used with every frame that is transmitted or received. Valid values include: (0) Parity None, (1) Parity Odd, (2) Parity Even, (3) Parity Mark, (4) Parity Space. Mark means that the parity bit exists and is always 1. Space means that the parity bit exists and is always 0.Serial Settings:Stop BitsSpecifies the number of stop bits used to indicate the end of a frame. Valid values include: (10) Stop One, (15) Stop One-and-a-Half, (20) Stop Two.Serial Settings:Wire ModeSpecifies the current wire/transceiver mode. For RS485 hardware, this property is valid only with the RS485 serial driver developed by National Instruments. For RS232 hardware, the values RS232/DCE and RS232/Auto are valid only with RS232 serial drivers developed by National Instruments and documented to support this feature with the corresponding National Instruments hardware. When this feature is not supported, RS232/DTE is the only valid value.TCP/IP Settings:Computer HostnameReturns the host name of the device. If no host name is available, this property returns an empty string.TCP/IP Settings:Dot-Notation AddressReturns the TCPIP address of the device to which the session is connected. This string is formatted in dot notation.TCP/IP Settings:HiSLIP Settings:Encryption EnabledControls and returns communication encryption.TCP/IP Settings:HiSLIP Settings:Maximum Message KBytesSpecifies the HiSLIP maximum message size in kilobytes, where a kilobyte is 1024 bytes.TCP/IP Settings:HiSLIP Settings:Overlap EnabledSpecifies whether the HiSLIP 'overlap' mode is enabled.TCP/IP Settings:HiSLIP Settings:Protocol VersionReturns the negotiated HiSLIP protocol version.TCP/IP Settings:HiSLIP Settings:SASL MechanismReturns a string that indicates the SASL mechanism used to authenticate the client.TCP/IP Settings:Is HiSLIPReturns whether this session is using the HiSLIP protocol to communicate with the device.TCP/IP Settings:Keep-Alive PacketsSpecifies whether to use keep-alive packets on TCP connections. Setting this property to TRUE requests that a TCP/IP provider enable the use of keep-alive packets on TCP connections. After the system detects a dropped connection, VISA returns a lost connection error code on subsequent I/O calls on the session. The time required for the system to detect the dropped connection depends on the system and is not settable. The default is FALSE.TCP/IP Settings:LAN Device NameReturns the LAN device name used by the VXI-11 protocol (for example, inst0) during connection.TCP/IP Settings:No Packet DelaySpecifies whether the Nagle algorithm is enabled. The Nagle algorithm is disabled when this property is TRUE (and vice versa). The Nagle algorithm improves network performance by buffering written data until a full-size packet can be sent. This property is TRUE by default in VISA to verify that writes get flushed immediately.TCP/IP Settings:Server Certificate Expiration DateReturns the expiration date of the server certificate. The form is ASN.1 UTCTime “YYMMDDhhmm[ss]Z.TCP/IP Settings:Server Certificate Is PerpetualIndicates the certificate does not expire.TCP/IP Settings:Server Certificate Issuer NameReturns the name of the CA that signed the certificate in RFC4514 format.TCP/IP Settings:Server Certificate Subject NameReturns the serial number and subject field from the certificate om RFC4514 format.TCP/IP Settings:TLS Cipher SuiteReturns a string that indicates the cipher suite used by TLS.USB Settings:Maximum Interrupt SizeSpecifies the maximum size of data stored by any given USB interrupt. If a USB interrupt contains more data than this size, the data in excess of this size is lost. This property is read/write when the corresponding session is not enabled to receive USB interrupt events. When the session is enabled to receive USB interrupt events, this property is read only.USB Settings:Serial NumberReturns the USB serial number of this device.USB Settings:USB Interface NumberReturns the USB interface number used by the given session.USB Settings:USB ProtocolReturns the USB protocol used by the given session.VXI/VME Settings:Destination Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Data/Privileged (0).VXI/VME Settings:Destination Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA Out X and VISA Move Out X, when writing to the destination. The default is Big Endian (0).VXI/VME Settings:Fast Data Channel:Channel ModeSpecifies whether FDC transfers use normal or streaming mode. The default is Normal.VXI/VME Settings:Fast Data Channel:Channel NumberSpecifies which FDC channel to use to transfer data buffers. Valid values include 0-7.VXI/VME Settings:Fast Data Channel:Use Channel PairsSpecifies whether transfers use a pair of FDC channels. If you do not set this property, transfers use only one FDC channel. The default is FALSE.VXI/VME Settings:Immediate ServantReturns whether the VXI device is an immediate servant of the local controller.VXI/VME Settings:Mainframe Logical AddressReturns the lowest logical address in the mainframe in which the device resides.VXI/VME Settings:Source Access PrivilegeSpecifies the address modifier to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Data/Privileged (0).VXI/VME Settings:Source Byte OrderSpecifies the byte order to use in high-level access operations, such as VISA In X and VISA Move In X, when reading from the source. The default is Big Endian (0).VXI/VME Settings:Supported VXI Trigger LinesReturns which VXI trigger lines this implementation supports. This property returns a bit vector with bits 0-9 corresponding to TTL0 through ECL1.VXI/VME Settings:VXI Commander Logical AddressReturns the logical address of the commander of the VXI device.VXI/VME Settings:VXI Device ClassReturns the class to which the VXI or VME device belongs.VXI/VME Settings:VXI Logical AddressReturns the logical address of the VXI device.VXI/VME Settings:VXI Memory Address SpaceReturns the VXI address space used by the device.VXI/VME Settings:VXI Memory Base AddressReturns the base address of the device in VXI memory space.VXI/VME Settings:VXI Memory SizeReturns the size of memory requested by the device in VXI memory space.VXI/VME Settings:VXI Trigger DirectionsSpecifies the directions of the mapped TTL triggers lines. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding line is routed out of the frame, and a value of 1 means the line is routed into the frame. Lines must be enabled using VXI/VME Settings:VXI Trigger Lines Enable.VXI/VME Settings:VXI Trigger Lines EnableSpecifies which VXI TLL triggers have mappings. This is a bit vector where bits 0-7 represent TTL triggers 0-7 respectively. A bit value of 0 means the corresponding trigger line is unmapped, and 1 means a mapping exists. Use VXI/VME Settings:VXI Trigger Directions to set an enabled line's direction.VXI/VME Settings:Window Access PrivilegeSpecifies the address modifier to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Data/Privileged (0).VXI/VME Settings:Window Byte OrderSpecifies the byte order to use in low-level access operations, such as VISA Map Address, VISA Peek X, and VISA Poke X, when accessing the mapped window. The default is Big Endian (0).Parent topic: I/O Session Properties