SCC-2345 showing non-zero values

[yellowleader]

I am using a DAQ pcmcia card with traditional NI-DAQ. When I look at the test panels for the SCC-2345 it shows non-zero values for most of the open channels. Why is this? Hopefully nothing is wrong with my scc box. Hope someone can help. Thanks!

[AnalogKid2DigitalMan]

DAQ card inputs are typically high impedance, when left unconnected, they are 'floating'. That is, charges and voltages can build up in the front end of the input and result in 'phantom' volatges being present.

For a sanity test, short the inputs of each of the analog channels, you should then read 0 volts. Likewise, apply a voltage to each input (say, using a 1.5v battery) and verify the reading displayed.

I once made an 'intrusion alert' vi that basically looked at the voltage impressed on a floating input with a few inches of wire connected to it. When a person approached, they would disturb the 60Hz EMI field and abruptly change the voltage on the input.

Let me know if the tests above work out.