E-Stop Lag... now part of our arm is broken

[Greg McKaskle]

I know that the arm damage has probably put you behind schedule, but please try to check things out to see what does and doesn't work and to verify you can trust the safety systems.

1. E-Stop the robot. The buttons aren't the most robust things, and if yours is broken, toss it. As mentioned, hitting spacebar disables the robot and is good to teach in addition or instead.

2. Break communications with the robot by pulling the enet cable on the cRIO. The outputs should stop due to the system watchdog.

3. Review code looking for logic issues that could lead to a wild value being computed.

4. Examine the digital breakout. In the very rare cases I've heard of where a robot moved even when disabled, it was due to a fused digital breakout board that didn't disable digital lines properly. I don't remember the exact issue, but it was a damaged board. That doesn't make sense with a PWM signal, but verify the board looks good anyway.

Please let us know if you see anything else that looks flaky, anything else that needs a close inspection or additional testing.

Greg McKaskle

[rwood359]

Originally Posted by Greg McKaskle

4. Examine the digital breakout. In the very rare cases I've heard of where a robot moved even when disabled, it was due to a fused digital breakout board that didn't disable digital lines properly. I don't remember the exact issue, but it was a damaged board.
Greg McKaskle

We had an incident this season where the fuse to the DSC was missing and the system was DISABLED, but one victor was enabled. It looked like the DSC was being back powered to some extent. The 5V LED was on, the BAT and 6V LEDs were off. After the fuse was installed, everything worked correctly.

[RyanN]

I found a few issues in the old code. Here's the new code if anyone wants to try having a look at it. I don't know if the question marks for the Joysticks, Motors, and PID will go away if someone with FRC LabVIEW opens it or not. I have plain ole' LabVIEW on my desktop computer at work, so none of those show up.

Here it is: Arm Control.vi

[jtdowney]

Originally Posted by Greg McKaskle

4. Examine the digital breakout. In the very rare cases I've heard of where a robot moved even when disabled, it was due to a fused digital breakout board that didn't disable digital lines properly. I don't remember the exact issue, but it was a damaged board. That doesn't make sense with a PWM signal, but verify the board looks good anyway.

We had something similar happen to us at a fall off-season event. The spike relays (nothing else) were firing while disabled and the RSL was never turning on. Our theory at the time was that the signal was getting crossed inside the digital side car. Replacing the side car got us running again but it was very odd and unsafe that our spikes started turning on randomly.

[bscharles]

As far as E-Stops not working how they should, we had a scary occurrence today at the WI regional. During one of the qualifying matches, i tried to move the telescoping part of our arm using position mode. The encoder wasn't plugged in correctly, so it kept on going outward. About halfway out, i slammed on the E-stop button, but the arm kept going. Even after hitting it numerous times, the arm never stopped until it ran itself off of the ball screw