Enclosure Altitude Display

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The Enclosure Display shows the status of the Enclosure Altitude Axis, also referred to as the Shutter.

The display includes on the left column the status of the permissive signals coming from the GIC: E-Stop, Seismic Alarm, Fire Alarm, and the GIC permissive signal (which should also be true).

The two lower indicators show the status of the Drive Enable signal to the main axis drives as well as Drive Power signal.

The center column includes local controller status information such as the E-Stop, Final Limit, Over speed, as well as shutter seal deflation status.

The right-most column show status of other local functions such as whether the trapped key is present, TEOA platform is stowed, Transfer Bridge gate closed status and the status of the Telescope Level Egress doors.

At the bottom of the display are GOTO buttons to navigate to other displays related the Enclosure, such as Enclosure Azimuth, Enclosure E-Stops, Aperture Cover, Rear Door, Cranes, and TEOA platform. As well as the standard navigation buttons of Home, Previous, Next, and Return.

GIC E-Stop

This indicates the status of the Emergency Stop from the GIC. Axis motion is inhibited if this is active. The indicator also functions as a GOTO button that will open the GIC E-Stop Display to enable further investigation of the cause.

Seismic Alarm

This indicates the status of the Seismic Alarm signal from the GIC.

Fire Alarm

This indicates the status of the Building Fire Alarm. Axis motion is inhibited if this is active.

GIC Permissive

This indicates the status of various GIC interlocks. Axis motion is inhibited if this is active.

If this signal is active then communications between the GIC and Enclosure LIC are not working properly.

E-Stop

This indicates the status of the Local Emergency Stop Devices. Axis motion is inhibited if this is active. The indicator also functions as a GOTO button that will open the Enclosure E-Stop Display to enable further investigation of the cause.

Final Limits

The Enclosure Altitude final limits monitor the position of the Enclosure Azimuth Axis to ensure it does not exceed mechanical limits.

If the Enclosure Altitude Axis has exceeded the allowable final limits the Enclosure Azimuth Axis must be manually moved out of the final limit.

1. Switch control to ‘Local’.

2. The Enclosure Altitude Axis Final Limit must be bypassed entering a passcode in the EMCS PLC. Set tag Alt_Limit_Final_Reached_PassWord to 7654321.

3. Manually drive the Enclosure Altitude Axis out of the limit while visually monitoring the motion.

Speed Limit

The maximum speed of the Enclosure Altitude Axis is monitored. If the speed limit is exceed the axis will be inhibited.

Shutter Seals

This indicator shows the status of the Shutter Seals. If the seals are not fully deflated the axis will be inhibited.

Trapped Keys

This indicator shows whether the proper trapped key is in place. Either of these conditions must be true:

• Trapped Key 'A' is in Cabinet 001

• Trapped Key 'B' is in Cabinet 503

TEOA Platform

This indicator shows the status of the TEOA platform drawbridge and guard rail.

Transfer Bridge

This indicator shows the status of the Transfer Bridge Gate. The gate must be properly closed or the axis will be inhibited.

Rear Door

This indicator shows the status of the rear door on the telescope level. The door must be properly closed or if it is open then the light curtain safety sensors must not be interrupted or the axis will be inhibited.

Overtension

This indicator shows the status of the Enclosure Altitude Cable Wrap overtension sensor.

Output Faulted

This indicator shows the status of the Drive Enable and Drive Power output safety functions. If either is faulted it must be cleared before enabling the axis.