Hello;
At this point, the problem might be anywhere. The best thing to do is to try nailing down the problem. If you can connect a battery signal to the SCXI module, and read its reaing from MAX - Test Panel, that would be the first troubleshooting step.
If you can see the proper voltage value of on Test Panel, that means the SCXI setup is correct, otherwise, I suggest you to go back and double check the SCXI configuration.
Hope this helps.
Filipe A.
Applications Engineer
National Instruments