Lab-PC+: Output Malfunction

[CBes]

I have a PC with a Lab-PC+ analogue I/O board controlling a series of pneumatic valves and reading in from a series of temperature and pressure sensors. Whilst the board has no problems reading into the PC, the output to the valve is not functioning despite no problems previously. The valve works when DC is applied directly to it but the PC will not output a signal itself.

Any suggestions?

[JoshuaP]

There are a couple of things you can check. The Lab-PC+ analog outputs are only rate for a max of +-2mA. If your valves are pulling to much current the voltage will stay near zero. You can double check this by disconnecting the analog outputs from everything and just connect a DMM to the analog outputs to see if they still work. I would use the test panel to generate the DC voltage for the test.

Make sure you check the specs on the valve to see how much current it requires in order to operate correctly. As a simple test, you could try hooking a DMM in series with the valve and the DC power supply you are using to test how much current is being drawn.

If you have an extra Lab-PC+ you could try to swap them out to see if it makes a difference. The last ca
se scenario is to send the device back in for repair.

Joshua