SCB68 thermocouple wiring

[usuario]

I want to acquire 10 thermocouple's readings. I have a 6062E & SCB68. My questions are:

- Which position should the switches be switch to? (CJC ON, acc. power on?)

- How do I perform each TC wiring? I mean, I understand TC should be read in Differential mode (not common mode). So then, I think I shouldn't use AIGND and each of the TC wires should be screwed in an AIXX, so that the relative reading can be obtained. Which AIXX should I use (say, one TC to AI2 & AI9, for example...)? How do I know how the AI channels are paired (I mean, how do I wire them, in which positions?), which one positive and which one negative?

- After wiring (say in AI2 & AI9) for example, when defining the physical channel in the .vi, which one should I reffer to: AI2, AI9, both??

- As for the CJC... Performing some trials, DAQAssistant gave me an error if all 3 channels I had selected had the BUILT IN option. Why is this? Can't I set a BUILT IN option? Do I have to wire a AO (trough CJC sensor may send its output) to an AI and select it? Which AO?

Thanks,

usuario

[dSierra]

Hello,

The switches position depends on what kind of measurement you would like to take. In page 8 of the SCB 68 manual you can see all the details. Normally, you would choose MIO with differential temperature sensor mode.

For wiring your thermocouples, you should set differential mode and just use each AI+ and AI- lines. For example in differential mode, AI1 will use AI1 terminal as positive input and AI9 as the negative one, channel AI2 will use AI2 and AI10 and so on... This means that channels AI8-16 will become the negative inputs for channels AI0 to AI7. Therefore, when referring to these channels, you should only refer to channels AI0 to AI7. You should not use AI0 since it is connected to the internal temperature sensor of the SCB-68

Maybe DAQAssistant is returning an error because you are trying to read from AI0.

Best regards.