Measurement Computing CIO-EXP-GP User Manual
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EXCITATION CURRENT (+)
SENSE HIGH (+)
SENSE LOW (-)
EXCITATION CURRENT (-)
4 WIRE
RTD
These connections eliminate the fixed inaccuracy
associated with the 2-wire RTD. Since virtually no
current flows on the sense lines, there is no voltage
drop in the sense lines. Thus, the error associated with
2-wire RTDs is eliminated. We recommend the 4-wire
RTD, but you must judge if the added cost is worth the
additional accuracy.
Figure 6-5. Four-Wire RTD Hookup
6.9 Verifying the Installation
To verify the installation, use the InstaCal program installed on your computer. This software came with
your A/D board if you bought the board from the same manufacturer as the CIO-EXP-GP. If your A/D
board is not from the same manufacturer but is compatible, please call technical support and request a
copy of InstaCal.
Use InstaCal's TEST option to verify that a signal present at one of the CIO-EXP-GP inputs can be read.
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