PXI-2527 Specifications
- Updated2024-03-25
- 10 minute(s) read
PXI-2527 Specifications
Definitions
Warranted specifications describe the performance of a model under stated operating conditions and are covered by the model warranty.
Characteristics describe values that are relevant to the use of the model under stated operating conditions but are not covered by the model warranty.
- Typical specifications describe the performance met by a majority of models.
- Nominal specifications describe an attribute that is based on design, conformance testing, or supplemental testing.
Conditions
Specifications are valid at 23 °C unless otherwise noted.
All voltages are specified in DC, ACpk, or a combination unless otherwise specified.
Topology
Topologies | 1-wire 64 × 1 multiplexer 1-wire dual 32 × 1 multiplexer 2-wire 32 × 1 multiplexer 2-wire dual 16 × 1 multiplexer 4-wire 16 × 1 multiplexer Independent |
Input
All input specifications are DC, ACrms, or a combination unless otherwise specified.
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Differential thermal EMF | 2.5 μV, typical[4]4 To ensure the typical thermal EMF, power down all relays and avoid pulsing high currents near the channels you are measuring. For more information about powering down latching relays, refer to the Power Down Latching Relays After Debounce property in NI-SWITCH or the Power Down Latching Relays After Settling property in NI-DAQmx. <12 μV, maximum |
Channel-to-channel DC leakage at 300 V | 500 GΩ |
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Dynamic
Expected
Relay Life
Mechanical | 1 × 108 cycles |
Electrical | 300 VDC, 60 mADC resistive | 5 × 105 cycles |
30 VDC, 2 ADC resistive | 1 × 105 cycles | |
<30 mV, <10 mA | 2.5 × 106 cycles |
Trigger
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Thermocouple Measurement
You can use the PXI-2527 and the TB-2627 to measure thermocouples. NI software can convert a thermocouple voltage to the thermocouple temperature. For example code, visit ni.com/examples, and enter PXI-2527 in the Search field.
When measuring thermocouples, be sure to account for error in your measurements. The total error in thermocouple measurement is the sum of the system error (determined by the thermal EMF of the PXI-2527 and the CJC temperature of the TB-2627) and the thermocouple error (determined by the type of thermocouple used).
Determining the System Error
To determine the system error for the PXI-2527 and TB-2627, first calculate the error due to thermal EMF of the PXI-2527 using the following equation:
where[7]7 In thermocouple reference tables, T and T+1 are known values used to calculate the slope of the thermocouple Temperature vs. Voltage graph. Refer to a thermocouple reference table to determine the values of V and V+1 that correspond to T and T+1, respectively.
- E EMF = error due to thermal EMF of the PXI-2527
- T = temperature being measured, in degrees Celsius
- T +1 = T + 1 °C
- V = voltage that corresponds to T
- V +1 = voltage that corresponds to T+1
- V EMF = thermal EMF of the PXI-2527[8]8 Refer to the Input section of this document to determine the thermal EMF value of the PXI-2527. For optimal thermocouple measurement performance (VEMF = 2.5 μV), power down the latching relays of the PXI-2527. For more information about powering down latching relays, refer to the Power Down Latching Relays After Debounce property in NI-SWITCH or the Power Down Latching Relays After Settling property in NI-DAQmx.
After you have determined the error due to thermal EMF, calculate the system error using the following equation.
E S = EEMF + ECJC
where
- E S = system error of the PXI-2527/TB-2627
- E EMF = error due to thermal EMF of the PXI-2527
- E CJC = error due to CJC temperature sensor of the TB-2627[9]9 From 15 °C to 35 °C, the TB-2627 has an accuracy of ±0.5 °C. From 0 °C to 15 °C and 35 °C to 55 °C, the TB-2627 has an accuracy of ±1.0 °C. For more information about temperature sensor accuracy, refer to the TB-2627 Installation Instructions.
Example
Measuring a K-type thermocouple at 200 °C with a CJC temperature of 25 °C, the system error of the PXI-2527/TB-2627 is calculated below.[10]10 In this example, the values of V and V+1 are found in the thermocouple reference tables of Omega Engineering’s The Temperature Handbook. Vol. 29. Stamford, CT: Omega Engineering Inc, 1995.
Assuming typical thermal EMF (2.5 μV), first calculate the error due to thermal EMF using the following equation:
To determine the system error, add the error due to thermal EMF to the error due to the CJC temperature sensor using the following equation.
E S = 0.063 °C + 0.5 °C = 0.563 °C
Determining the Thermocouple Error
Independent of the PXI-2527/TB-2627 system, thermocouple error is the greater of the following values: ±temperature range or ±percent of the measurement.
In the example, a standard grade K-type thermocouple is used to measure 200 °C. The error for a standard grade K-type thermocouple is ±2.2 °C or ±0.75% of the measurement temperature.[11]11 Omega Engineering. The Temperature Handbook. Vol. 29. Stamford, CT: Omega Engineering Inc, 1995. Because ±0.75% of 200 °C (±1.5 °C) is less than ±2.2 °C, the error of a standard grade K-type thermocouple is ±2.2 °C.
Determining the Total Error
The total error in thermocouple measurement is the sum of the system error and the thermocouple error. Use the following equation to determine the total error in thermocouple measurement:
E T = ES + ETh
where
- E T = total error in thermocouple measurement
- E S = system error
- E Th = thermocouple error
To determine the total error in thermocouple measurement in the example, add the thermocouple error to the system error using the following equation:
E T = 0.56 °C + 2.2 °C = 2.76 °C
Assuming typical thermal EMF, the total error in thermocouple measurement at 200 °C for the PXI-2527/TB-2627 with a K-type thermocouple is ±2.76 °C.
Physical
Relay type | Electromechanical, latching |
Relay contact material | Palladium-ruthenium, gold covered |
I/O connector | 100-position HDI right angle, male |
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Dimensions (L × W × H) | 3U, one slot, PXI/cPCI module 21.6 cm × 2.0 cm × 13.0 cm (8.5 in. × 0.8 in. × 5.1 in.) |
Weight | 209 g (7.4 oz) |
Environment
Operating temperature | 0 °C to 55 °C |
Storage temperature | -20 °C to 70 °C |
Relative humidity | 5% to 85%, noncondensing |
Pollution Degree | 2 |
Maximum altitude | 2,000 m |
Indoor use only.
Shock and Vibration
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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1 Switching inductive loads (for example, motors and solenoids) can produce high voltage transients in excess of the module’s rated voltage. Without additional protection, these transients can interfere with module operation and impact relay life. For more information about transient suppression, visit ni.com/info and enter the Info Code induct.
2 The minimum switch load is not recommended for 2-wire resistance measurements.
3 DC path resistance typically remains low for the life of the relay. At the end of relay life, the path resistance rapidly rises above 1 Ω. Load ratings apply to relays used within the specification before the end of relay life.
4 To ensure the typical thermal EMF, power down all relays and avoid pulsing high currents near the channels you are measuring. For more information about powering down latching relays, refer to the Power Down Latching Relays After Debounce property in NI-SWITCH or the Power Down Latching Relays After Settling property in NI-DAQmx.
5 Certain applications may require additional time for proper settling. Refer to the NI Switches Help for more information about including additional settling time.
6 The PXI-2527 can recognize trigger pulse widths less than 150 ns if you disable digital filtering. Refer to the NI Switches Help for information about disabling digital filtering.
7 In thermocouple reference tables, T and T+1 are known values used to calculate the slope of the thermocouple Temperature vs. Voltage graph. Refer to a thermocouple reference table to determine the values of V and V+1 that correspond to T and T+1, respectively.
8 Refer to the Input section of this document to determine the thermal EMF value of the PXI-2527. For optimal thermocouple measurement performance (VEMF = 2.5 μV), power down the latching relays of the PXI-2527. For more information about powering down latching relays, refer to the Power Down Latching Relays After Debounce property in NI-SWITCH or the Power Down Latching Relays After Settling property in NI-DAQmx.
9 From 15 °C to 35 °C, the TB-2627 has an accuracy of ±0.5 °C. From 0 °C to 15 °C and 35 °C to 55 °C, the TB-2627 has an accuracy of ±1.0 °C. For more information about temperature sensor accuracy, refer to the TB-2627 Installation Instructions.
10 In this example, the values of V and V+1 are found in the thermocouple reference tables of Omega Engineering’s The Temperature Handbook. Vol. 29. Stamford, CT: Omega Engineering Inc, 1995.
11 Omega Engineering. The Temperature Handbook. Vol. 29. Stamford, CT: Omega Engineering Inc, 1995.