KRC4 Enabling Switch Timeout Error

Howdy all,

Background:

We have a "new" (purchased from Kuka in the last 6 months, not run more than a few hours) KR 500 MT with a KRC4 controller, mounted on a Gudel rail. The robot has been moveable for a few weeks now, and we have been working on linking I/O to an external PLC and getting the safety system up and running to begin manufacturing with it.

Problem:

After a project upload, the pendant began to display the following warning (see pic):

"Enabling switch timeout. Release enabling switch and press it again"

This error prevents us from moving the robot even in "Service > Startup Mode", and cannot be confirmed.

Attempted Solutions:

- We cold booted the robot - the error still exists after restart

- We switched pendants with another identical robot that we have in the shop that runs normally - the error persists

- We reverted to an older WorkVisual project that we keep around to troubleshoot these kinds of errors - it's a minimal project, no I/O linking, that just integrates the rail. The error persists.

Thoughts:

Since we were doing some I/O mapping, a possible guess is that we mapped some high input to a section of the $IN array that is used for deadman switch monitoring? This doesn't make sense, though, as the older project has no such mapping, and the error persists.

Not a lot online about this error that basic search has given me. We have a ticket in with Kuka right now. Any of y'all got ideas?

Alright, we've solved the problem, and have a good guess at why it happened.

Our PLC, even when we changed our WV project, was writing a TRUE value to $IN[140]. This input is marked as used by the system, and (presumably) controls the activation switch. We didn't notice because we were doing grouping in WorkVisual, 16 bytes at a time.

Solution:

1. Unlink any $IN bits marked with "SYS" in your PLC system

2. Upload WV project without IO linking (we factory reset the robot, but I reckon it doesn't matter so long as the IO

3. Cold Boot the robot.

Not fully sure that this is how to fix it, but we're pretty loathe to start trying to reproduce the error. To whomever reads this next, godspeed.