Compressor will not start!

[DangitDrBob]

Hello! Team 4135 Programmer here.

We are having issues with our compressor. It will not start when we tell it to with our program. We are using C++ and Wind River to program it. We do not get any errors when compiling the program, and our robot does everything else that it is supposed to. We have the Vex Spike relay plugged into the compressor and the digital side car relay port 1. The Pressure Switch is plugged into the digital side car Digital I/O port 1. All of the code that pertains to the compressor is as follows (but in the right spots):

Compressor Ac; //Declaring the compressor
Ac(1,1), //Digital I/O port 1, Relay port 1
Ac.Start(); //Run the compressor

If you want the whole code I have attached it in a .txt file so that you can see the whole thing. We have tried to program the compressor purely as a relay ( Relay Ac; Ac(1); Ac.Set(Relay:: kOn); ) The Spike relay does not change colors from the default red/orange when we run the program. We have tested the Spike relay and its fuse and both are working properly. We have tried swapping all of the wires involved. The Digital Side Car's power lights are lighting up (all three), but the LED lights next to the relay port are NOT lighting up. We tested the compressor by hooking it up directly to a battery and it worked. We have tried using a brand new Digital Side Car but to no avail. We think think the problem may be with DSC, the cRIO or something in that area. Any suggestions would be greatly appreciated!! Thanks!

[eddie12390]

Hello! Team 4135 Programmer here.

We are having issues with our compressor. It will not start when we tell it to with our program. We are using C++ and Wind River to program it. We do not get any errors when compiling the program, and our robot does everything else that it is supposed to. We have the Vex Spike relay plugged into the compressor and the digital side car relay port 1. The Pressure Switch is plugged into the digital side car Digital I/O port 1. All of the code that pertains to the compressor is as follows (but in the right spots):

Compressor Ac; //Declaring the compressor
Ac(1,1), //Digital I/O port 1, Relay port 1
Ac.Start(); //Run the compressor

If you want the whole code I have attached it in a .txt file so that you can see the whole thing. We have tried to program the compressor purely as a relay ( Relay Ac; Ac(1); Ac.Set(Relay:: kOn); ) The Spike relay does not change colors from the default red/orange when we run the program. We have tested the Spike relay and its fuse and both are working properly. We have tried swapping all of the wires involved. The Digital Side Car's power lights are lighting up (all three), but the LED lights next to the relay port are NOT lighting up. We tested the compressor by hooking it up directly to a battery and it worked. We have tried using a brand new Digital Side Car but to no avail. We think think the problem may be with DSC, the cRIO or something in that area. Any suggestions would be greatly appreciated!! Thanks!

This might be a dumb question, but have you tried flipping around the cable in the DSC/relay? We've had issues with one of the two being backwards in the past. Do your motors / digital IO work correctly? If so, I don't think it's the DSC or the cRIO as a failure in either is unlikely.

[DangitDrBob]

We just tried it and it didn't change anything. Yes, the motors and Digital I/O both work. We can drive it around still, but the compressor will not start. We have also check with last year's code which worked, but it didn't work on this robot.

[eddie12390]

We just tried it and it didn't change anything. Yes, the motors and Digital I/O both work. We can drive it around still, but the compressor will not start. We have also check with last year's code which worked, but it didn't work on this robot.

Can you try another Relay port on the DSC?

[DangitDrBob]

We have tried that it did not work.

[Joe Ross]

You are not initializing the objects in the same order they are declared.

Just to verify, if you remove the DB-37 cable from the Digital Sidecar, are all 3 power LEDs on the Digital Sidecar brightly lit?


We just tried it and it didn't change anything. Yes, the motors and Digital I/O both work. We can drive it around still, but the compressor will not start. We have also check with last year's code which worked, but it didn't work on this robot.

What does this mean? Can you describe in more detail what you did and what did and didn't work?

[Matt C]

We have tested the Spike relay and its fuse and both are working properly. !

After you do get the software side ironed out, you may want to replace your fuse with a 20A breaker when the fuse blows after the first couple times your compresser kicks on.

R64
E. If powering the compressor, the fuse on a Spike H-Bridge Relay may be replaced with a 20A Snap-Action circuit breaker.

[Jasmine Zhou]

For relay testing, try running it as Ac.Set(Relay::kForward); instead of Relay::kOn. That should run the compressor and turn the light on the spike green. Forward and reverse aren't the same as on; someone who knows more can explain that. If that works, then the spike and its connections are good.
Also make sure your pressure switch is working and wired properly: if it's not sending signal to the digital sidecar, the compressor won't (shouldn't) run.

[Andy A.]

Forward and reverse aren't the same as on; someone who knows more can explain that.

The simple answer is that 'on' means both output terminals of the spike are at +12 volts, as opposed to 'forward' or 'reverse' where one is + and the other -.

The utility being that 'on' allows you to power two loads connected to a shared ground. It's not a common thing in FRC, to the point I wasn't really aware of the functionality till it showed up as a 'bug' in this years code. The obvious use would be running two solenoids with one spike. In that case, 'forward' or 'reverse' would power one load but not the other, and 'on' would power both.

[matthewdenny]

We had an issue getting our compressor to work also. Turns out the pressure switch was broken. You can test this by simply shorting the 2 terminals on the switch to close the circuit and seeing it that fixes the issue. If it does, try replacing the pressure switch.

[DangitDrBob]

Thanks for all the suggestions. We called the support and they helped us fix things.