Regarding the Spike relay. The Users manual for a blue spike manual is located at:
http://www.ifirobotics.com/docs/spik...uide-sep05.pdf
The users manual indicates that the indicator is orange when both solenoids are off. When the Relay is set to the "forward" direction, the M+ is connected to the +12, and the indicator will be green (i.e when the indicator is green, the compressor should be running).
Here's what I would do:
1. Disconnect the power, ground, M+, M- wires from the Spike relay (leave the PWM/relay cable hooked up).
2. In LabVIEW, open the Relay Example vi.
3. Set the Relay Channel to the relay that you are using.
4. Set the Relay Direction to forward only (compressor only runs in "forward" direction).
5. Run the Relay Example VI and set the Relay Value to Off and then to Forward.
a. When you set the Relay Value to Off, the relay indicator should turn orange.
b. When you set the Relay Value to Forward, the indicator light should turn green.
6. Test the continuity between connections to see if they are what you expect. When Relay Value is Off, both M+ and M- should be connected with ground. When relay value is Forward, I would expect
a. continuity between Ground and M-
b. continuity between +12 and M+
If the above all works quit the Relay Example VI and test the pressure switch:
7. Open the Simple Digital Input Example vi.
8. Set the DIO channel to be the same as your pressure switch.
9. Run Simple Digital Input Example.vi to see if the pressure switch is really closed (it should be if there's no pressure).
10. If that's working, then stop and close the Simple Digital Input Example.vi
11. open the Solenoid with Compressor Example.vi
12. run the Solenoid with Compressor Example.vi
13. test for continuity as above in step 6.
If this is all working, then you should be able to hook up the power wires and the compressor wires, and it should work.
-Nate