We are trying to use the relay ports on the Roborio. Hooking the relay up to battery we can control it. We have used multi-meters on the relay port on the Rio and have confirmed when they send 5V.
We can use the relay port to power the relay and the VCC LED illuminates with kReverse. However, when we energize both with kOn it appears the relay browns out. Is it possible the Rio doesn’t have enough power to energize the relay?
While the issue has been resolved, I feel it is worth mentioning what is going on here.
The RoboRIO’s “Relay” ports are meant to run “H-Bridge Relays” or a “DPDT” delay. As such the 3-pins are actually “A”,“B”,“gnd” not “sig”,“5v”,“gnd” like the analog and digital pins are. With A and B each controlling one pole of the output being High or Low. Some more details can be checked out here: https://nvhs.wordpress.com/project/catspberry/motor-controller/
Traditionally these would be used for “Spike” H-Bridge Relays, like shown here, https://www.therobotspace.com/ProductDetails.asp?ProductCode=vex-217-0220, which would be used for the compressor, 12v solenoids, and sometimes running very small motors, but after they were discontinued, and we got the Pneumatic Control Module, they just weren’t as necessary anymore, and have fallen out of use. With most older teams having a collection of them on the shelf.