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RTD or Thermistor Measurements with the SCXI-1303 Terminal Block

Hardware: SCXI>>Terminal Blocks>>SCXI-1303, SCXI>>Modules>>SCXI-1102

Problem:
Is it possible to make RTD or Thermistor measurements with the SCXI-1102 module and SCXI-1303 terminal block?

Solution:
The SCXI-1581 current excitation module user manual recommends using the SCXI-1300 terminal block when making RTD or Thermistor measurements, but the SCXI-1303 can also be used. In order to use RTDs or Thermistors with the SCXI-1303 terminal block, you must supply external current excitation and remove the 10 MOhm pullup and bias resistors. Since these bias resistors are in packs of 8, you will be able to have banks of 8 RTD/Thermistor or thermocouple measurements connected to the SCXI-1303. The following table indicates which resistor packs perform each function.


Resistor Pack Signal Connection
RP5 (pullup) CH0(+) - CH7(+)
RP1 (bias) CH0(-) - CH7(-)
RP6 (pullup) CH8(+) - CH15(+)
RP2 (bias) CH8(-) - CH15(-)
RP7 (pullup) CH16(+) - CH23(+)
RP3 (bias) CH16(-) - CH23(-)
RP8 (pullup) CH24(+) - CH31(+)
RP4 (bias) CH24(-) - CH31(-)



Note: When skipping channels in DAQmx on the 1102, you must still account for the channels skipped in the maximum sample rate calculation, as the module must multiplex these channels onto the SCXI bus in order to proceed to subsequent channels. For instance, if you want to acquire data on channels 0 and 3, you will be effectively scanning 4 channels (0, 1, 2, and 3) for maximum sample rate calculations, but the DAQmx driver only returns data for channels 0 and 3.

Related Links: SCXI-1581 User Manual
SCXI-1102/B/C User Manual
SCXI-1303 32-Channel Isothermal Terminal Block Installation Guide
Thermocouple Measurements Concept Document
Measuring Temperature with an RTD or Thermistor

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Report Date: 11/28/2005
Last Updated: 07/19/2007
Document ID: 3RRGIKZA

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