Update 2024-09-12: C. Fisher confirms this is actually normal behaviour. The Y-axis motion is inhibited when X and Z are in a certain configuration, which was true when the manipulator was mounted on the wall in storage position. Non-issue. A note about this has been made in the operator manual.

It was observed today that for the spare manipulator (Model N, Serial 9351), the Y-axis motion was not functioning. X motion and Z motion are functioning as expected. Note that the Y-axis linear actuator was recently replaced and successfully tested and has not been used since the replacement (see e-log 2422).

The following information was determined from troubleshooting:

• X motion functioning correctly
• Z motion functioning correctly
• Y motion selection functioning correctly - the indicator light on the operator control box lights up to confirm Y is selected, and the relay on the main control board which selects the Y axis toggles, as expected
• Y motion motor contactors do not function as expected when toggling in either direction. Note that these contactors are shared in common with the other two motion axes, so they are functioning correctly and presumably the motor controller itself is as well, since the other axes work.
• Most likely, because of the above reasons, there is an issue with the inhibit signal that is specific to the Y axis. The inhibit signal which runs from the main control board to the motor control board is shared in common with all motion axes (same for the two direction select signals). It is suspected (not yet confirmed), that the microcontroller is not outputting the inhibit signal as it should be. This is not due to a limit switch related issue because the Y axis does not have limits. Troubleshooting this has been difficult because the schematics do not show the full extent of the circuitry.

Further troubleshooting steps:

1. Check inhibit signal functionality - is it working for Y axis?
2. Check direction control signal functionality - are they working for Y axis?
3. Swap motor select wires to "trick" the microcontroller into thinking it is running a different motor, to further isolate the issue.
4. If required, swap the entire main control board with another manipulator's, to see if the issue is related to the circuitry which is not described in the schematics.

At the time, this issue is not deemed critical because this is a spare unit.