AuxTel Mount Fails to Move

Overview

This troubleshooting procedure is necessary when the AuxTel mount experiences a failure to move, specifically due to the azimuth max velocity error exceeded. Users will observe the telescope remaining stuck with ATMCS reporting FAULT.

Error diagnosis

When attempting to move the telescope via point_azel or Scheduler, the faults are the followings:

  • The ATMCS get FAULT state , ATMCS provides specific error messages indicating FAULT` in azimuth drives #1 and #2, with both FAULT bits activated.

  • The ATPtg get FAULT state

Traceback Error
 Fault event in ATMCS while in tracking enable state.
 Azimuth max velocity error  exceeded. ATMCS Real-Time Application.vi/MOUNTDEV.vi
 /Generic Device.lvclass:Run.vi:1530004/MOUNTDEV.lvclass:NormalDeviceLogic.vi/MOUNTDEV.
 lvclass:ProcessDeviceLogicStateTransitions.vi/MntcTrackEnabledState.lvclass:
 ProcessStateTransition.vi/mount_fault_state_procedure.vi
Traceback Error
 Fault event in ATMCS while in tracking enable state.
 Azimuth drive #2 fault bit is ON. Azimuth drive #1 fault bit is ON.
 Azimuth max velocity error exceeded. ATMCS Real-Time Application.vi/
 MOUNTDEV.vi/Generic Device.lvclass:Run.vi:1530004/MOUNTDEV.lvclass:
 NormalDeviceLogic.vi/MOUNTDEV.lvclass:ProcessDeviceLogicStateTransitions.vi/
 MntcTrackEnabledState.lvclass:ProcessStateTransition.vi/mount_fault_state_procedure.vi

Procedure Steps

Note

Make sure everything is in a safe or idle state before troubleshooting.

To resume observations, nudge the telescope out of its position by slewing only in altitude to lower elevation. Then, nudge it incrementally in azimuth, starting with 1-2 degree increments to then increasing to 20-degree increments.

From LOVE

  1. Stop the Scheduler and clear any pending scripts. From the queue, send the auxtel/scheduler/stop.py script.

  2. Cycle the ATMCS and ATPtg. If necessary, to CSCs to STANDBY and back to ENABLE.

  3. Slew the telescope in small increments using the auxtel/point_azel.py script.

    1. If the telescope is pointing at a higher elevation, move it lower.

    2. Start with azimuth and elevation coordinates close to the current position, for instance, from Az= 57.64 deg move to Az=58.00 deg.

    3. If the initial azimuth-only nudge fails, try nudging in the opposite azimuth direction.

    4. Gradually increase the amplitude of azimuth slews.

    Example sequence of successful slews:

    STEP

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    Azimuth

    57.64

    58

    60

    58

    56

    54

    40

    20

    1

    80

    120

    150

    Elevation

    45

    45

    45

    45

    45

    45

    45

    45

    45

    45

    45

    60

  4. Resume Scheduler, if desired.