NI 6255 Specifications
- Updated2023-02-18
- 13 minute(s) read
NI 6255 Specifications
Analog Input
Number of channels | 40 differential or 80 single ended | ||||||||||||||||||
ADC resolution | 16 bits | ||||||||||||||||||
DNL | No missing codes guaranteed | ||||||||||||||||||
INL | Refer to the AI Absolute Accuracy section | ||||||||||||||||||
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Timing resolution | 50 ns | ||||||||||||||||||
Timing accuracy | 50 ppm of sample rate | ||||||||||||||||||
Input coupling | DC | ||||||||||||||||||
Input range | ±0.1 V, ±0.2 V, ±0.5 V, ±1 V, ±2 V, ±5 V, ±10 V | ||||||||||||||||||
Maximum working voltage for analog inputs (signal + common mode) | ±11 V of AI GND | ||||||||||||||||||
CMRR (DC to 60 Hz) | 100 dB | ||||||||||||||||||
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Input bias current | ±100 pA | ||||||||||||||||||
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Small signal bandwidth (-3 dB) | 1.7 MHz | ||||||||||||||||||
Input FIFO size | 4,095 samples | ||||||||||||||||||
Scan list memory | 4,095 entries | ||||||||||||||||||
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Input current during overvoltage condition | ±20 mA maximum/AI pin |
Settling Time for Multichannel Measurements
Range | ±60 ppm of Step (±4 LSB for Full-Scale Step) | ±15 ppm of Step (±1 LSB for Full-Scale Step) |
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±1 V, ±2 V, ±5 V, ±10 V | 1.3 μs | 1.6 μs |
±0.5 V | 1.8 μs | 2.5 μs |
±0.1 V, ±0.2 V | 3 μs | 8 μs |
Typical Performance Graphs
AI Absolute Accuracy
Nominal Range Positive Full Scale | Nominal Range Negative Full Scale | Residual Gain Error (ppm of Reading) | Residual Offset Error (ppm of Range) | Offset Tempco (ppm of Range/°C) | Random Noise, σ (μVrms) | Absolute Accuracy at Full Scale (μV) | Sensitivity (μV) |
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10 | -10 | 60 | 20 | 21 | 280 | 1,920 | 112.0 |
5 | -5 | 70 | 20 | 21 | 140 | 1,010 | 56.0 |
2 | -2 | 70 | 20 | 24 | 57 | 410 | 22.8 |
1 | -1 | 80 | 20 | 27 | 32 | 220 | 12.8 |
0.5 | -0.5 | 90 | 40 | 34 | 21 | 130 | 8.4 |
0.2 | -0.2 | 130 | 80 | 55 | 16 | 74 | 6.4 |
0.1 | -0.1 | 150 | 150 | 90 | 15 | 52 | 6.0 |
Gain tempco | 13 ppm/°C |
Reference tempco | 1 ppm/°C |
INL error | 60 ppm of range |
AI Absolute Accuracy Equation
AbsoluteAccuracy = Reading · (GainError) + Range · (OffsetError) + NoiseUncertainty
- GainError = ResidualAIGainError + GainTempco · (TempChangeFromLastInternalCal) + ReferenceTempco · (TempChangeFromLastExternalCal)
- OffsetError = ResidualAIOffsetError + OffsetTempco · (TempChangeFromLastInternalCal) + INLError
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NoiseUncertainty = for a coverage factor of 3 σ and averaging 100 points.
AI Absolute Accuracy Example
Absolute accuracy at full scale on the analog input channels is determined using the following assumptions:
- TempChangeFromLastExternalCal = 10 °C
- TempChangeFromLastInternalCal = 1 °C
- number_of_readings = 100
- CoverageFactor = 3 σ
For example, on the 10 V range, the absolute accuracy at full scale is as follows:
- GainError = 60 ppm + 13 ppm · 1 + 1 ppm · 10 = 83 ppm
- OffsetError = 20 ppm + 21 ppm · 1 + 60 ppm = 101 ppm
- NoiseUncertainty = = 84 µV
- AbsoluteAccuracy = 10 V · (GainError) + 10 V · (OffsetError) + NoiseUncertainty = 1,920 µV
Analog Triggers
Number of triggers | 1 | ||||||||||
Source | AI <0..79>, API 0 | ||||||||||
Functions | Start Trigger, Reference Trigger, Pause Trigger, Sample Clock, Convert Clock, Sample Clock Timebase | ||||||||||
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Resolution | 10 bits, 1 in 1,024 | ||||||||||
Modes | Analog edge triggering, analog edge triggering with hysteresis, and analog window triggering | ||||||||||
Accuracy | ±1% | ||||||||||
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Analog Output
Number of channels | 2 | ||||||
DAC resolution | 16 bits | ||||||
DNL | ±1 LSB | ||||||
Monotonicity | 16 bit guaranteed | ||||||
Accuracy | Refer to the AO Absolute Accuracy section | ||||||
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Timing accuracy | 50 ppm of sample rate | ||||||
Timing resolution | 50 ns | ||||||
Output range | ±5 V, ±10 V, ±external reference on APFI 0 | ||||||
Output coupling | DC | ||||||
Output impedance | 0.2 Ω | ||||||
Output current drive | ±5 mA | ||||||
Overdrive protection | ±25 V | ||||||
Overdrive current | 20 mA | ||||||
Power-on state | ±5 mV [2] | ||||||
Power-on glitch | 1.5 V peak for 1.5 s | ||||||
Output FIFO size | 8,191 samples shared among channels used | ||||||
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AO waveform modes | Non-periodic waveform, periodic waveform regeneration mode from onboard FIFO, periodic waveform regeneration from host buffer including dynamic update | ||||||
Settling time, full-scale step, 15 ppm (1 LSB) | 2 µs | ||||||
Slew rate | 20 V/µs | ||||||
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External Reference
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AO Absolute Accuracy
Absolute accuracy at full-scale numbers is valid immediately following internal calibration and assumes the device is operating within 10 °C of the last external calibration.
Nominal Range Positive Full Scale | Nominal Range Negative Full Scale | Residual Gain Error (ppm of Reading) | Gain Tempco (ppm/°C) | Residual Offset Error (ppm of Range) | Offset Tempco (ppm of Range/°C) | Absolute Accuracy at Full Scale (μV) |
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10 | -10 | 75 | 17 | 40 | 2 | 2,080 |
5 | -5 | 85 | 8 | 40 | 2 | 1,045 |
Reference tempco | 1 ppm/°C |
INL error | 64 ppm of range |
AO Absolute Accuracy Equation
AbsoluteAccuracy = OutputValue · (GainError) + Range · (OffsetError)
- GainError = ResidualGainError + GainTempco · (TempChangeFromLastInternalCal) + ReferenceTempco · (TempChangeFromLastExternalCal)
- OffsetError = ResidualOffsetError + AOOffsetTempco · (TempChangeFromLastInternalCal) + INLError
Digital I/O/PFI
Static Characteristics
Number of channels | 24 total, 8 (P0.<0..7>), 16 (PFI <0..7>/P1, PFI <8..15>/P2) |
Ground reference | D GND |
Direction control | Each terminal individually programmable as input or output |
Pull-down resistor | 50 kΩ typical, 20 kΩ minimum |
Input voltage protection | ±20 V on up to two pins[3] |
Waveform Characteristics (Port 0 Only)
Terminals used | Port 0 (P0.<0..7>) | ||||||||||||||||||
Port/sample size | Up to 8 bits | ||||||||||||||||||
Waveform generation (DO) FIFO | 2,047 samples | ||||||||||||||||||
Waveform acquisition (DI) FIFO | 2,047 samples | ||||||||||||||||||
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DI or DO Sample Clock source[4] | Any PFI, RTSI, AI Sample or Convert Clock, AO Sample Clock, Ctr n Internal Output, and many other signals |
PFI/Port 1/Port 2 Functionality
Functionality | Static digital input, static digital output, timing input, timing output |
Timing output sources | Many AI, AO, counter, DI, DO timing signals |
Debounce filter settings | 125 ns, 6.425 µs, 2.56 ms, disable; high and low transitions; selectable per input |
Recommended Operating Conditions
Level | Minimum | Maximum |
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Input high voltage (VIH) | 2.2 V | 5.25 V |
Input low voltage (VIL) | 0 V | 0.8 V |
Output high current (IOH) P0.<0..7> | — | -24 mA |
Output high current (IOH) PFI <0..15>/P1/P2 | — | -16 mA |
Output low current (IOL) P0.<0..7> | — | 24 mA |
Output low current (IOL) PFI <0..15>/P1/P2 | — | 16 mA |
Electrical Characteristics
Level | Minimum | Maximum |
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Positive-going threshold (VT+) | — | 2.2 V |
Negative-going threshold (VT-) | 0.8 V | — |
Delta VT hystersis (VT+ - VT-) | 0.2 V | — |
IIL input low current (Vin = 0 V) | — | -10 µA |
IIH input high current (Vin = 5 V) | — | 250 µA |
Digital I/O Characteristics
General-Purpose Counters/Timers
Number of counter/timers | 2 | ||||||
Resolution | 32 bits | ||||||
Counter measurements | Edge counting, pulse, semi-period, period, two-edge separation | ||||||
Position measurements | X1, X2, X4 quadrature encoding with Channel Z reloading; two-pulse encoding | ||||||
Output applications | Pulse, pulse train with dynamic updates, frequency division, equivalent time sampling | ||||||
Internal base clocks | 80 MHz, 20 MHz, 0.1 MHz | ||||||
External base clock frequency | 0 MHz to 20 MHz | ||||||
Base clock accuracy | 50 ppm | ||||||
Inputs | Gate, Source, HW_Arm, Aux, A, B, Z, Up_Down | ||||||
Routing options for inputs | Any PFI, RTSI, PXI_TRIG, PXI_STAR, analog trigger, many internal signals | ||||||
FIFO | 2 samples | ||||||
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Frequency Generator
Number of channels | 1 |
Base clocks | 10 MHz, 100 kHz |
Divisors | 1 to 16 |
Base clock accuracy | 50 ppm |
Output can be available on any output PFI or RTSI terminal.
Phase-Locked Loop (PLL)
Number of PLLs | 1 |
Reference signal | PXI_STAR, PXI_CLK10, RTSI <0..7> |
Output of PLL | 80 MHz Timebase; other signals derived from 80 MHz Timebase including 20 MHz and 100 kHz Timebases |
External Digital Triggers
Source | Any PFI, RTSI, PXI_TRIG, PXI_STAR |
Polarity | Software-selectable for most signals |
Analog input function | Start Trigger, Reference Trigger, Pause Trigger, Sample Clock, Convert Clock, Sample Clock Timebase |
Analog output function | Start Trigger, Pause Trigger, Sample Clock, Sample Clock Timebase |
Counter/timer function | Gate, Source, HW_Arm, Aux, A, B, Z, Up_Down |
Digital waveform generation (DO) function | Sample Clock |
Digital waveform acquisition (DI) function | Sample Clock |
Device-to-Device Trigger Bus
PCI | RTSI <0..7>[5] |
PXI | PXI_TRIG <0..7>, PXI_STAR |
USB source | None |
Output selections | 10 MHz Clock, frequency generator output, many internal signals |
Debounce filter settings | 125 ns, 6.425 μs, 2.56 ms, disable; high and low transitions; selectable per input |
Bus Interface
PCI/PXI | 3.3 V or 5 V signal environment |
USB | |
DMA channels (PCI/PXI) | 6, can be used for analog input, analog output, digital input, digital output, counter/timer 0, counter/timer 1 |
USB Signal Stream | 4, can be used for analog input, analog output, counter/timer 0, counter/timer 1 |
The PXI device can be installed in PXI Express hybrid slots. It cannot be used to control SCXI in PXI/SCXI combo chassis.
Power Requirements
USB power supply requirements | 11 to 30 VDC, 20 W, locking or non-locking power jack with 0.080 in. diameter center pin, 5/16-32 thread for locking collars |
Current Limits
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Physical Characteristics
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Screw Terminal/BNC screw terminal wiring | 16 AWG to 28 AWG |
Calibration
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Calibration interval | 2 years |
Maximum Working Voltage
Connect only voltages that are below these limits.
Channel-to-earth | 11 V, Measurement Category I |
Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics.
Environmental
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Storage temperature | -20 ºC to 70 ºC | ||||||
Humidity | 10% RH to 90% RH, noncondensing | ||||||
Maximum altitude | 2,000 m | ||||||
Pollution Degree (indoor use only) | 2 |
Indoor use only.
Shock and Vibration (PXI Only)
Operational shock | 30 g peak, half-sine, 11 ms pulse (Tested in accordance with IEC 60068-2-27. Test profile developed in accordance with MIL-PRF-28800F.) | ||||||
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Safety Compliance Standards
This product is designed to meet the requirements of the following electrical equipment safety standards for measurement, control, and laboratory use:
- IEC 61010-1, EN 61010-1
- UL 61010-1, CSA C22.2 No. 61010-1
Electromagnetic Compatibility
CE Compliance
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- 2011/65/EU; Restriction of Hazardous Substances (RoHS)
Product Certifications and Declarations
Refer to the product Declaration of Conformity (DoC) for additional regulatory compliance information. To obtain product certifications and the DoC for NI products, visit ni.com/product-certifications, search by model number, and click the appropriate link.
Environmental Management
NI is committed to designing and manufacturing products in an environmentally responsible manner. NI recognizes that eliminating certain hazardous substances from our products is beneficial to the environment and to NI customers.
For additional environmental information, refer to the Engineering a Healthy Planet web page at ni.com/environment. This page contains the environmental regulations and directives with which NI complies, as well as other environmental information not included in this document.
EU and UK Customers
电子信息产品污染控制管理办法(中国RoHS)
Device Pinouts
1 Channel AI <0..15> crosstalk to channel AI <64..79> is -67 dB. This applies to channels with 64-channel separation. Example: AI (x) and AI (x + 64).
2 When the USB Screw Terminal device is powered on, the analog output signal is not defined until after USB configuration is complete.
3 Stresses beyond those listed under Input voltage protection may cause permanent damage to the device.
4 The digital subsystem does not have its own dedicated internal timing engine. Therefore, a sample clock must be provided from another subsystem on the device or an external source.
5 In other sections of this document, RTSI refers to RTSI <0..7> for the PCI devices or PXI_TRIG <0..7> for PXI devices.
6 If you are using an USB M Series device in full-speed mode, device performance will be lower and you will not be able to achieve maximum sample/update rates.
7 Operating on a full-speed bus may result in lower performance.
8 Does not include P0/PFI/P1/P2 and +5 V terminals.
9 Older revisions have a self-resetting fuse that opens when current exceeds this specification. Newer revisions have a traditional fuse that opens when current exceeds this specification. This fuse is not customer-replaceable; if the fuse permanently opens, return the device to NI for repair.
In This Section
- Analog Input
- Analog Triggers
- Analog Output
- Digital I/O/PFI
- General-Purpose Counters/Timers
- Frequency Generator
- Phase-Locked Loop (PLL)
- External Digital Triggers
- Bus Interface
- Power Requirements
- Current Limits
- Physical Characteristics
- Calibration
- Maximum Working Voltage
- Environmental
- Shock and Vibration (PXI Only)
- Safety Compliance Standards
- Electromagnetic Compatibility
- CE Compliance
- Product Certifications and Declarations
- Environmental Management
- Device Pinouts