Air Compressor Will Not Initiate

[Slothbron]

Originally Posted by Alan Anderson

You believe it's wired properly. Why should we believe it? The proper wiring is pretty simple. Tell us how you've done it so we can confirm it. It's often best to double-check the simple stuff before putting forth much effort trying to think of what else might be wrong.

Ok so we have a pwm cable coming from the spike relay of the air compressor to relay spot 1 on the sidecar. Then the pressure switch is wired to the DIO spot 1 on the sidecar. Specifically the signal pin and + pin.

[Alan Anderson]

Originally Posted by Slothbron

Ok so we have a pwm cable coming from the spike relay of the air compressor to relay spot 1 on the sidecar. Then the pressure switch is wired to the DIO spot 1 on the sidecar. Specifically the signal pin and + pin.

For a switch input to be read by the program, you need to use the signal pin and the ground (-) pin. The Digital Sidecar inputs are already at +5 volts when nothing is connected to them. You have to pull them low in order to register a change.

[Slothbron]

Ok so you fixed the pins now we have one wire going to the signal and one to the negative. But it will still not start when we enable the robot.

[Alan Anderson]

Originally Posted by Slothbron

Ok so you fixed the pins now we have one wire going to the signal and one to the negative. But it will still not start when we enable the robot.

I assume you followed Greg's advice to make the compressor control loop active in Periodic Tasks?

Disconnect the pressure switch from the Digital Sidecar and measure continuity between the contacts. They should be shorted together when the pressure is too low. If there is an open circuit, replace the switch. Check the Digital Sidecar and look to see whether the relay is being asked to turn on (there should be a green LED lit next to the pins for relay #1). If it is, look at the LED on the Spike (it should change from yellow to green when the robot is enabled).