Compressor troubleshooting

[Hieb]

I'm having issues getting the compressor to turn on.

- I'm running the compressor example code to make sure it is not a coding issue.
- The pressure switch is plugged in to DIO1 on the DSC. I've also switched out the pressure switch to make sure it is not the switch.
- The spike is receiving its signal from Relay1 on the DSC. I've replaced the pwm cable with a brand new cable.
- I've directly powered the compressor to make sure it runs.
- The DSC is powered and all 3 lights are green.
- The Relay1 light is green on the DSC (does this mean signal is being sent to the spike? I think so but can't remember as I type this).
- The dashboard shows the switch is on and the compressor is running.
- I changed the data cable from the cRIO to the DSC.

- The light on the spike is on and amber, but never changes to green. I've replaced the spike to make sure it isn't the spike.


What else can I try? I can't think of anything else in the loop to test.

Thanks

[Hieb]

OK, 2 things I thought of while typing the original post:

-I'll change the code to send signal to Relay2 in case there is a problem with that output on the DSC.

-I'll change the circuit breaker on the spike in case it is bad.

[ASmith1675]

Your assumption is correct about the green light on the DSC indicating that the signal is being sent to the spike to turn on. It seems like you've done a good job of proving out all the individual hardware. The main issue seems to be that the signal is not getting to the spike, as that light should be turning green to run the compressor.

If I had to guess, I would say that the PWM is probably plugged in backwards on one end between the DSC and the spike (can't count how many times I've done this myself). Working from memory here, on the DSC the white side of the PWM should be towards the middle of the board, and on the spike the black wire should be closest to the 'B'.

Hope this helps. Good luck.

[Hieb]

I think I've double and triple checked the pwm positioning but I'll check again when I get the chance. Thanks.

[Mark McLeod]

A couple of tests you can try:

1. Use a multimeter to test the Relay signal/ground on the Sidecar. It'll be a steady 4.6v on one of the two signal pins matching position with the green LED. The other pin will read 0v.
2. Use a multimeter on the far end of the PWM cable to see if the voltage is getting there.

P.S.
If you are getting a green LED lit for the Relay, then the code and pneumatic setup has ordered the compressor to turn on.
Don't bother looking at the pressure switch or code at this point.
The next stop in the command stream is that the Spike LED color should be matching the green Relay LED color.
If the Spike LED doesn't match the Relay LED, then there is the failure is between the Relay output and the Spike - PWM cable, reversed plug, plug not making contact, Relay output under powered, Spike failure.

[brennonbrimhall]

You didn't mention that you had a reservoir hooked up into your system. I assume you do, but if not, the compressor can easily pressurize an entire robot's tubing in a fraction of a second. It turns on, but not long enough to notice.

[Hieb]

I'll try the multimeter tests if I can find my multimeter (my school decided to move us in to a new room in the middle of the build so all of our tools and equipment was randomly placed in to boxes that we are still digging through).

Originally the pressure switch was in-line with the reservoir system, but I currently have the switch out of the system entirely so it should never reach pressure and always run.