After quite a bit of testing, I think we need to replace our pressure switch for our compressor to turn on. We manually tested our system by connecting it directly to the 12v battery and we were able to confirm our system holds air, all gauges are working, and we can manually fire our pneumatics cylinders. One we connected to the robot using the CTRE pcm, we can’t get the compressor to turn on. We used the phoenix tuner and to update all firmware, we also updated the PCP and roborio. I think it’s gotta be the switch. Anyway, I am looking for a cheaper, quicker option than studica. 44$ plus 25$ to ship.
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Short answer: Given your situation, you’ll need to buy a new Nason switch. (But, before you do: check it on an oscilloscope or multimeter.) Best bet is going to be finding someone who stocks it in Canada (that isn’t Studica).
That said, there’s an alternate, but it’ll take some investment. REV’s analog pressure sensor is only $35, BUT is only legal for use with REV’s Pneumatic Hub ($90)
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Are you entirely sure you have your system wired correctly ? before your out and buy something maybe validate the connections with the wiring diagram for your pcm.
I will take a picture of the pneumatics prototyping board we built. I will post tomorrow.
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Just to make sure, are you enabling the robot in the driver station?
Short the pressure switch wires together. If the compressor does not start. Something else is keeping it from running.
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Have you tested bypassing the switch by temporarily connecting the switch terminals (using a jumper cable or even the shaft of a screwdriver)?
edit: 1m too late 
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This is definitely the next step, before buying anything. At events, inspectors should short the pressure switch (or use the mode button on Rev’s board if you have the analog one) to confirm the compressor relief valve’s operational set point, so it’s a good process to experience/practice at home, especially if the pneumatic system isn’t working and you suspect the pressure switch to be the problem.
If you want to test the switch itself, independent of everything else, you could hook it up to a shop compressor. Use the regulator on the shop compressor to run up the pressure to the switch (with a plug after the switch) and watch the results with a multimeter. You should see it trip around 115-120 PSI, then you can go the other way, dropping the pressure until you see it switch back. Great way to show kids how it works safely!
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Here is a video of our prototyping board
It might take a few minutes to finish processing.
Yes you did one version of what I said. But not the version I meant. In your version the pressure switch is not connected to the PCM. Therefore it has no effect on the program logic. If you look on the PCM you will see where the pressure switch should be connected. If you connect the pressure switch to those two terminals and short the wires together that bypasses the pressure switch and the compressor should run with the robot enabled.
The pressure switch is a normally closed switch that opens when it reaches set pressure (115ish psi) or 792 KPA for decimal impaired friends.
After I did it and thought about it, I realized no power would be running through it at all LoL. I understand the screw driver short method across the terminals. I’ll try that.
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I only do crayon Java so I can’t give detail code. But general to get the PCM to work.
The PCM has to be sustantionated in code (or whatever the right word is.) Make sure than canbus address in code is the same as the physical one. WPLIB sort of assumes it is 0
Define at one soleniod variable to be safe.
Once the PCM is talking it the code. The compressor runs automatically. You can force it off by code, but you don’t have to.
Thanks for the tip. Check the video of me shorting the switch. The compressor comes on. So is it a coding error?
The code that controls the compressor is correct if the switch controls the compressor. I was just listing possibilities if it was not.
After shorting the switch and letting the compressor run, i noticed there is air flowing through it because you can feel it when you open the pressure release value. However, the gauges are not changing at all. Would a faulty gauge affect the system?
Gauges should not affect the electronic side of things. It does take time to fill if it’s empty.
It takes a lot longer if there’s a valve open to atmosphere…
If it runs when you short the switch, it should run when the pressure is low (under the same conditions, robot enabled, etc.). If you have a multimeter, you can test the switch – with no pressure, the two terminals should be internally connected together (by the sensor, don’t add an external wire to connect them together). If not, you probably do have a bad pressure switch.
With the switch shorted, i made a little more progress. I replumbed some of the air hoses. I know the tanks flow in one direction so there was air going in but it was never coming out. The video shows that the system is holding air and I can manually fire the cylinders again which is nice. I haven’t put the multimeter on the switch yet. I still think it could be the switch. Can someone confirm the plumbing is okay? What other tests can I run?
Everyone’s help has been great so far. Thank you. I am try to show my students how great this forum is too and hoping they can take the lead in troubleshooting some of our future issues
The tanks shouldn’t restrict airflow in either direction, but you might have the pressure regulator backwards… (It’s hard to tell from the images. I don’t have one of these on hand, but IIRC, there’s an arrow molded in somewhere that is supposed to go from high pressure – compressor side – to low pressure – cylinder side.)
If the cylinders are working, everything might be OK. Check your pressure gauges. The high should be at ~120psi (although this depends on the pressure switch) and the low is adjustable but normally ~60psi. Since you don’t have a working switch, take care not to run the compressor once the high gauge gets over maybe 115psi.