SCXI 1303 Isolation

[Rabi B]

It appears as though the first 16 channels of the SCXI 1303 thermocouple module
are not attached to ground - that is: if one uses a voltmeter and tests,
one will see that channels 16-31 are tied to the module's ground while 0-15
are not. I believe this may be the cause of a measurement error we are experiencing
- as we are using channels 0 through 12 we are unsure what to do with the
negative leads of the thermocouples which we have attached differentially
to the module. Is one supposed to tie all the leads to a common ground somewhere
else?
Rabi B.

[Brent B.]

The SCXI-1303 has bias resistors for floating signals and pull-up resistors for open TC detection actually socketed into the terminal block. If you look in the SCXI-1303 Installation Guide, you will see that there are four banks of these resistors. If some of these resistor banks have been removed, this could be the reason why some channels are biased to ground and others are not.