AuxTel LOTO Procedure

Overview

AuxTel must be under LOTO (lock-out tag-out) any time physical work is undertaken on the mount or the dome. When working with environmental sensors, on the truss, mirrors, or anywhere in the dome where unexpected movement could cause a safety hazard, the telescope must be locked out. Trained summit support staff may use this procedure if they meet all of the precondition requirements.

Precondition

Before putting the AuxTel under LOTO, you must have completed the LOTO safety training and familiarized yourself with the Control Safety Systems document on that same page. You should have your own unique lock and key with your information identified, and this work must be coordinated with the day crew.

  • The telescope must be parked in a safe position, and all CSCs in STANDBY.

    • If the ATDome is needed while the AuxTel is under LOTO, this must be verified with the safety team and day crew.

    Warning

    The ATDome can still be controlled or moved even if this LOTO procedure is complete. The ATDome needs to be locked out separately if any electronics work will be undertaken or work is done on the dome drive.

  • The work should be scheduled in the SUMMIT JIRA calendar and day crew as well as nighttime support should be aware of the plan.

Post-Condition

The drives are powered off and the AuxTel Control cabinet is locked from the outside. The AuxTel is under LOTO and is not able to move by any controls.

Procedure Steps

To put the AuxTel under LOTO, follow these steps:

  1. Post in the Slack channels #summit-announce and #summit-auxtel that you are going to put AuxTel under LOTO.

  2. Announce your intentions on the radio (channel 3).

  3. Verify that no one is working in the dome, on the ground or second floors.

  4. Identify the AT Control cabinet that you need to lock out, shown in the figure.

../../../_images/AT-control-cabinet.png

AT Control cabinet, inside, and EATON brakers.

  1. Inside the AT Control cabinet, identify the three (3) EATON breakers also shown in the figure, tagged from left to right.

    1. DRV #1 AZ AZ - The two drives for Azimuth motion.

    2. DRV #2 EL M3 - The drives for elevation and tertiary mirror motion.

    3. DRV #3 NR1 NR2 - Motors for the Nasmyth rotators 1 and 2.

  2. Switch off all three breakers by flipping the switch down.

  3. Close the cabinet, and secure your lock and tag in the loop underneath the cabinet door handle.

  4. Verify that the AuxTel will not move intentionally by sending a command with the Engineering User Interface (EUI) on the machine located on the first floor.

    Or, simply verify that the EUI screen shows that the telescope E-STOP is engaged as seen in the figure below.

    ../../../_images/eui-estop-display.png

    The AuxTel EUI shows that the E-STOP is applied.

  5. AuxTel is under LOTO, and work may begin.

Troubleshooting

No troubleshooting information is applicable to this procedure. In the IMPOSSIBLE event that the telescope moves after turning off all three breakers, stop work immediately and notify the day crew, including Jacques Sebag, Mario Rivera, and the electronics team.

This procedure was last modified Dec 15, 2024.