AOChannel Class
- Updated2023-02-21
- 10 minute(s) read
AOChannel Class
Encapsulates one or more analog output channels and the properties for an analog output channel.
Inheritance Hierarchy
SystemObject
SystemMarshalByRefObject
NationalInstruments.DAQmxChannel
NationalInstruments.DAQmxAOChannel
SystemMarshalByRefObject
NationalInstruments.DAQmxChannel
NationalInstruments.DAQmxAOChannel
Namespace: NationalInstruments.DAQmx
Assembly: NationalInstruments.DAQmx (in NationalInstruments.DAQmx.dll) Version: 20.7.40.49302
Syntax
public class AOChannel : Channel, IFilteredTypeDescriptor
Public Class AOChannel Inherits Channel Implements IFilteredTypeDescriptor
The AOChannel type exposes the following members.
Properties
| Name | Description | |
|---|---|---|
 | CommonModeOffset | Specifies the common-mode offset of the AO channel. Use the property only when Terminal Configuration is set to Differential. |
| CurrentUnits | Specifies in what units to generate current on the channel. Write data to the channel in the units you select. |
| CustomScaleName | Specifies the name of a custom scale for the channel. |
| DacAllowConnectReferenceToGround | Specifies whether to allow grounding the internal DAC reference at run time. You must set this property to and set DacReferenceSource to Internal before you can set DacConnectReferenceToGround to . |
| DacConnectReferenceToGround | Specifies whether to ground the internal DAC reference. Grounding the internal DAC reference has the effect of grounding all analog output channels and stopping waveform generation across all analog output channels regardless of whether the channels belong to the current task. You can ground the internal DAC reference only when DacReferenceSource is Internal and DacAllowConnectReferenceToGround is . |
| DacOffsetExternalSource | Specifies the source of the DAC offset voltage if DacOffsetSource is External. The valid sources for this signal vary by device. |
| DacOffsetSource | Specifies the source of the DAC offset voltage. The value of this voltage source determines the full-scale value of the DAC. |
| DacOffsetValue | Specifies in volts the value of the DAC offset voltage. To achieve best accuracy, the DAC offset value should be hand calibrated. |
| DacRangeHigh | Specifies the upper limit of the output range of the device. This value is in the native units of the device. On E Series devices, for example, the native units is volts. |
| DacRangeLow | Specifies the lower limit of the output range of the device. This value is in the native units of the device. On E Series devices, for example, the native units is volts. |
| DacReferenceExternalSource | Specifies the source of the DAC reference voltage if DacReferenceSource is External. The valid sources for this signal vary by device. |
| DacReferenceSource | Specifies the source of the DAC reference voltage. The value of this voltage source determines the full-scale value of the DAC. |
| DacReferenceValue | Specifies in volts the value of the DAC reference voltage. This voltage determines the full-scale range of the DAC. Smaller reference voltages result in smaller ranges, but increased resolution. |
| DataTransferMechanism | Specifies the data transfer mode for the device. |
| DataTransferRequestCondition | Specifies under what condition to transfer data from the buffer to the onboard memory of the device. |
| Description | Specifies a user-defined description for the channel. (Inherited from Channel.) |
| DeviceScalingCoefficients | Indicates the coefficients of a linear equation that NI-DAQmx uses to scale values from a voltage to the native format of the device. Each element of the array corresponds to a term of the equation. The first element of the array corresponds to the y-intercept, and the second element corresponds to the slope. Scaling coefficients do not account for any custom scales that may be applied to the channel. |
| EnhancedImageRejectionEnable | Specifies whether to enable the DAC interpolation filter. Disable the interpolation filter to improve DAC signal-to-noise ratio at the expense of degraded image rejection. |
| FilterDelay | Specifies the amount of time between when the sample is written by the host device and when the sample is output by the DAC. This value is in the units you specify with FilterDelayUnits. |
| FilterDelayAdjustment | Specifies an additional amount of time to wait between when the sample is written by the host device and when the sample is output by the DAC. This delay adjustment is in addition to the value indicated by FilterDelay. This delay adjustment is in the units you specify with FilterDelayUnits. |
| FilterDelayUnits | Specifies the units of FilterDelay and FilterDelayAdjustment. |
| FunctionGenerationAmplitude | Specifies the zero-to-peak amplitude of the waveform to generate in volts. Zero and negative values are valid. |
| FunctionGenerationFMDeviation | Specifies the FM deviation in hertz per volt when FunctionGenerationModulationType is FM. |
| FunctionGenerationFrequency | Specifies the frequency of the waveform to generate in hertz. |
| FunctionGenerationModulationType | Specifies if the device generates a modulated version of the waveform using the original waveform as a carrier and input from an external terminal as the signal. |
| FunctionGenerationOffset | Specifies the voltage offset of the waveform to generate. |
| FunctionGenerationSquareDutyCycle | Specifies the square wave duty cycle of the waveform to generate. |
| FunctionGenerationType | Specifies the kind of the waveform to generate. |
| Gain | Specifies in decibels the gain factor to apply to the channel. |
| IdleOutputBehavior | Specifies the state of the channel when no generation is in progress. |
| IsGlobal | Indicates whether the channel is a global channel. (Inherited from Channel.) |
| LoadImpedance | Specifies in ohms the load impedance connected to the analog output channel. |
| Maximum | Specifies the maximum value you expect to generate. The value is in the units you specify with a units property. If you try to write a value larger than the maximum value, NI-DAQmx generates an error. NI-DAQmx might coerce this value to a smaller value if other task settings restrict the device from generating the desired maximum. |
| MemoryMappingEnable | Specifies for NI-DAQmx to map hardware registers to the memory space of the application, if possible. Normally, NI-DAQmx maps hardware registers to memory accessible only to the kernel. Mapping the registers to the memory space of the application increases performance. However, if the application accesses the memory space mapped to the registers, it can adversely affect the operation of the device and possibly result in a system crash. |
| Minimum | Specifies the minimum value you expect to generate. The value is in the units you specify with a units property. If you try to write a value smaller than the minimum value, NI-DAQmx generates an error. NI-DAQmx might coerce this value to a larger value if other task settings restrict the device from generating the desired minimum. |
| OutputImpedance | Specifies in ohms the impedance of the analog output stage of the device. |
| OutputType | Indicates whether the channel generates voltage, current, or a waveform. |
| PhysicalName | Specifies the name of the physical channel upon which this virtual channel is based. (Inherited from Channel.) |
| ReglitchEnable | Specifies whether to enable reglitching. The output of a DAC normally glitches whenever the DAC is updated with a new value. The amount of glitching differs from code to code and is generally largest at major code transitions. Reglitching generates uniform glitch energy at each code transition and provides for more uniform glitches. Uniform glitch energy makes it easier to filter out the noise introduced from glitching during spectrum analysis. |
| Resolution | Indicates the resolution of the digital-to-analog converter of the channel. This value is in the units you specify with ResolutionUnits. |
| ResolutionUnits | Specifies the units of Resolution. |
| SynchronizationUnlockBehavior | Specifies the action to take if the target loses its synchronization to the grand master. (Inherited from Channel.) |
| TerminalConfiguration | Specifies the terminal configuration of the channel. |
| Type | Indicates the type of the virtual channel. (Inherited from Channel.) |
| UsbTransferRequestCount | Specifies the maximum number of simultaneous USB transfers used to stream data. Modify this value to affect performance under different combinations of operating system and device. |
| UsbTransferRequestSize | Specifies the maximum size of a USB transfer request in bytes. Modify this value to affect performance under different combinations of operating system and device. |
| UseOnlyOnBoardMemory | Specifies whether to write samples directly to the onboard memory of the device, bypassing the memory buffer. Generally, you cannot update onboard memory directly after you start the task. Onboard memory includes data FIFOs. |
| VirtualName | Gets the name of the virtual channel. (Inherited from Channel.) |
| VoltageCurrentLimit | Specifies the current limit, in amperes, for the voltage channel. |
| VoltageUnits | Specifies in what units to generate voltage on the channel. Write data to the channel in the units you select. |
Methods
| Name | Description | |
|---|---|---|
 | CreateObjRef | Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.) |
| Dispose | Releases all resources used by Channel. (Inherited from Channel.) |
 | Dispose(Boolean) |
Releases the managed and unmanaged resources used by Channel or optionally releases only the unmanaged resources.
(Inherited from Channel.) |
| Equals | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetLifetimeService | Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| InitializeLifetimeService | Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.) |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| MemberwiseClone(Boolean) | Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.) |
| ToString | Returns a string representation of the object. (Inherited from Channel.) |
Remarks
Use the AOChannels property to create or access an analog output channel. An AOChannel might contain more than one virtual channel because the AOChannel is defined by providing a valid NI-DAQmx channel string to the AOChannels indexer or to an AOChannelCollection create channel method. If you set a property on a AOChannel object that represents multiple channels, that property is set for all of the channels that the object represents.
 Tip |
|---|
| Example applications are located in the Public Documents\National Instruments\NI-DAQ\Examples\DotNET4.x directory or in the Start menu at National InstrumentsNI-DAQmxNI-DAQmx Examples. |
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.