TCS Systems Control Failure 2

Wednesday, May 10, 2017 11:05 AM

Problem(s) Encountered:

The telescope would not move in the Dec direction. Point or offset commands in the E/W direction moved the telescope, but any command

involving N/S threw a ''point not converging'' error; JSkyCalc also could not move the telescope. The hand paddle GUI was able to move the telescope in the E/W direction and did not throw errors for N/S offsets, but it was obvious from the tilt meter that the paddle would not move the telescope N/.

I restarted the tcs services and the control panel, but nothing changed. I homed the dome, moved the telescope to zenith, and used ''zero'', following suggestions in the trouble report archive, but without success. Finally, I tried to home the Dec axis. This failed (ERROR home axis=m_dec fatal following error), and then the telescope would not move at all because it did not know where it was. Further attempts to move the telescope with the hand paddle led to  ERROR in service ether=localhost,0x1341  and shut

down the rtel service, which required a ''telescope stop'' and ''telescope start'' to fix.

I then used ''home force dec'' to force the telescope to recognize its location, and then ''zero''ed it at zenith. This re-enabled pointing/offset, but Declination motion still failed. I stowed the telescope and gave up for the night.


Found the dec drive controller to be issuing an error (err 131) upon inspection.  Cycled the 220V knife switch and all is well.  Did not have to home any drives.  Moved telescope and dome around via TCS command without issue.  All servers continue to respond positively.  This issue likely occurred when line power was restored (we’d been on generators for roughly 48 hours) last night.  The changeover can be somewhat abrupt and I’ve seen the dec drive power system behave badly during such changeovers in the past.

For future reference, I’m including some images of where the driver system is located and what knife switch to cycle in the event this happens again.