AuxTel Emergency Shutdown

Overview

Unfavorable circumstances that indicate the need to close the dome if it is open are:

• Weather constraints

• Sunrise approaching in the next two hours.

• Power outage affecting the dome shutter mechanism.

Precondition

The dome shutter is open and an unforeseeable condition arises, forcing an emergency dome closure.

Post-Condition

• The emergency situation has been clearly notified to the relevant personnel and management.

• Steps to eliminate or minimize the risk to the instruments and hardware are being implemented.

• Eventually, the dome shutter is closed and all equipment is safe.

Procedure Steps

In the event of an emergency dome closure, the dome shutter won’t be able to be operated from the standard CSC controls. The AuxTel dome would need to be closed manually. In case of sudden inclement weather, be very cautious and start closing early.

Warning

If you are dealing with a dome shutter emergency shutdown. Proceed calmly to keep the equipment safe. Please use the standard safety measures when visiting the dome enclosure. Safety of personnel always goes first.

Shutter Closure

1. Communicate on the #summit-announce channel that the observing crew is going to attempt to close the AuxTel dome via the emergency procedure.

2. Go up to the AuxTel dome (second floor). Locate the control box at the top of the stairs. The top black button should close the shutter. Note that the safety gate at the bottom of the stairs needs to be closed and locked in order for this button to operate.

3. If the above step fails, locate the AuxTel cRIO box. This box rotates with the AuxTel dome. Open it and identify the cRIO switches.

With EXTREME CAUTION slide the switch labeled “CLOSE” (yellow arrow) progressively to the left. This is a low-level control switch and there are no limit switches or fail-safes. It is best to stop the shutter movement about 1 cm before it is fully closed to prevent you over drive the shutter until it bangs into the lower shutter or cause damage on the drive.

Shutter Closure without Power

1. In the absence of electrical power, the shutter must be closed manually. On AuxTel first floor there is a crank that fits into a ring at the top of the dome. Rotating the ring manually with the crank assistance close the shutter. Note this is a long and physically demanding procedure and the hand crank just does not have enough torque to lift the weight of the shutter if it is all the way open. If you cannot safely insert the crank into the drive motor and operate the crank, then remove the crank and do not proceed.

Contingency

If the procedure was not successful, report the issue on the #summit-announce channel and/or activate the Out of hours support.

This procedure was last modified Nov 19, 2024.