In what case, will all motors on my robot flash red light?

All the motors on my robot suddenly flash in red in the same time. May there be something worry with the link of CAN?

It depends on what Motor Controller you are using. For SPARK MAXes, solid red just indicates “full reverse”.

More information about the REV Status Indicators can be found at: https://docs.revrobotics.com/sparkmax/status-led

Unfortunately, I don’t have much familiarity with the CTRE and Talon FX/SRX family, so I can’t offer any specific recommendations, but common things to look for in your CAN Bus:

  • Ensure that the start of your loop starts at the Rio, and ends at the PDP/PDH.
  • Ensure that your CAN bus is properly terminated (either with a 120Ω resistor, or if it ends at your PDP/PDH, that the Terminating Resistor is on).
  • When daisy chaining your motor controllers, ensure that your connections are in the correct orientation, as in, Yellow to Yellow, and Green To Green.
  • Look for any tears/rips in wires or any loose connections on the bus as well.
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Several weeks ago, we had a similar problem and the cause was the program. When driving, all four of the SparkMax’s would simultaneously flash purple, indicating they were all commanded to be off. I don’t recall what error our programmers made butit is likely to be different from the error your programmers made.

It is highly unlikely the condition you are seeing is due to bad wiring. A bad connection will not make the motor controllers think they have been commanded to go to full reverse.

WE need to know more. What controller are you using, when does it blink (operation, disabled …) how fast does it blink.

Falcon codes say you might be disconnected from the can or have another fault. Can you see the motors controllers in phoenix if ctre or rev hardware client? Can id collisions or bad wiring can cause issue.

One way to start analyzing is the process of elimination. Simplify your can to RIO to 1 motor to terminator (110 resistor or power distribution) . See if you can bring that up. If so keep expanding your can 1 motor at a time until you find the error. If you are impatient, still start with one, but maybe do a binary division approach and go from 1 to half you can instead of 1 to 2. If it succeeds add half the remaining can, if it fails reduce the can in half.

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