What can cause the errors in temperature measurement with SCXI1102 and SCXI1180

[aliko]

I have two modules(SCXI-1102 and SCXI-1180) in a SCXI-1100 chassis. From one module(SCXI-1102) I would like to read the temperatures. However I get wrong values from that modules if both modules are connected to the chassis. What can be the resaon for that? I would be also happy if you could send me information about how I can configure SCXI-1180 to measure voltage.
Thanks

[LucaP.]

Hi Aliko

There are differnt things to test.
1. Be sure that you define the right terminal blocks for the 1102/1180 in the accessory tab in MAX. Check that the settings of the modules are OK.
2. Which kind of temperature sensor are you using? Create a virtual channel (data neighborhood) with the right sensor type in MAX and test it than.

Look at the User Manual for the 1180 to see how it's working. Check this link too:http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/8672680db6add97286256aae0054c26c?OpenDocument
Don't forget, the 1180 is only a feedthrough panel! Usually you use SXCI Modules in multiplexed mode (setting in MAX). That means that all channel of the different modules (except 1180) are multiplexed to channel 0 of the DAQ board. That
means that other analog inputs are unused. With the 1180 you can access them on the front of the chassis. From there you can use them as "usual" analog inputs.

Hope this helps.

Luca P.
Applications Engineer
National Instruments

[Filipe A.]

Hello;

The 1180 is only a feedthroug module which gives access to the unused DAQ board channels, meaning you can hook up sensors to the analog channels, access the unused digital lines and use both general purpose counters of the DAQ device. You don't need any special configuration on that SCXI module.

Regarding the bad readings, it's really strange that one module is interfering on the readings of the other. The are completely independent.

Try to realibrate the 1102 module, and do some reading only with that module. Once you get the readings on that module right, you can hook up the 1180 without any problems.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments