How to measure different signals with PXI-2501

[RomanJ]

Hello everybody,

i have a an understanding problem.

I have a PXI-2501 switch and i want to measuere signals with the pxi-4071, so far so good.

I did some voltage- measurements and everything worked fine. Then i disconnected the power source and measured the temperature with a PT1000 in four-wire-mode ... also worked fine.

But i want to measure voltage and temperature, in the same VI, so i connected the voltage signal on CH0 and the PT1000 at CH5 (in four wire mode), and now i get problems. The temperature is fluctating. There are a few measurements that seems OK, and then i see some that are far away from the truth.

The VI consists of a state machine, the measurements are done in different states, of course with the correct scan list for each measurement.

Any suggestions? Am I doing something completely wrong?

Thanks

(and excuse for my english )

[HeinzG.]

Hi Roman,

id I understand you right:

The temperature measurement works fine, if the sensor is directly connected to the 4071, but if connected via the 2501 you see the big deviations?

Have you measured the the resistance of the Switch-Matrix yet?

kind regards 

Heinz