Mount Control System

MCS is part of TCS. It runs on tcs computers. Its main purpose is to provide GUI for MCSPU. RA/Dec tracking is controlled by PCS, which sends requests directly to MCSPU.

digraph G { rankdir=LR compound=true node[shape=box, style=filled] subgraph cluster_tcs { label="tcs1, tcs2" TCS[fillcolor=gray] MCS[fillcolor=lightblue] }

subgraph cluster_jet { label="jet" MCSPU[fillcolor=gold] }

subgraph cluster_hw { labe="HW" node[shape=house,fillcolor=lightyellow] Azimuth Elevation Rotators SwingArms HBS DynamicBalance Encoders }

TCS->MCS MCS->MCSPU MCSPU->SwingArms[lhead=cluster_hw] }

The MCS system allows access to the mount control software which runs on jet.mountain.lbto.org (in the level 5 auxiliary control room, also known as doghouse). That computer and its software are commonly referred to as the "MCSPU". The MCS subsystem has very little control function itself. It is a TCS-level interface for the MCSPU. MCS provides

• A TCS client interface to the MCSPU which can be used by other TCS subsystems to call MCSPU commands.
• Status and control GUIs for nearly all the MCSPU commands and subsystems.
• Maintains "severity" flags for the LBT Alarm system.
• Collects HBS telemetry.
• Maintains the "all-on-source" and "side-on-source" flags which are used by other TCS subsystems.

For a presentation on the MCS see https://wiki.lbto.org/pub/Software/MCS/MCS.pdf

So the MCS is largely just a GUI driven front-end for the MCSPU software. The MCSPU controls:

• The Azimuth and Elevation drive motors.
• The Azimuth and Elevation brakes.
• Elevation stow pins.
• Four instrument rotators (LUCI-1, LUCI-2, MODS/PEPSI) and their associated cable chains.
• The mount Drive Cabinet (Power supplies).
• Enclosure Rotation.
• Hydrostatic Bearing system.
• Swing Arms
• Dynamic balance.
• Mirror Covers (to be installed in 2018)

Historically, the MCSPU preceded the TCS so it began as a stand-alone system, and it is still a stand-alone system. MCSPU responds to requests for status information from the MCS (or any other TCS subsystem), and responds to commands from the TCS, but it has no dependence on the TCS. The TCS can be completely stopped and MCSPU will still run the same way it always does. It cannot make the telescope track or guide without commands from PCS, but it always provides manual control of the mount, swingarms, rotators, hydrostatic bearing, etc. If the TCS is unavailable, the operator can use the Engineering Interface to interact with the MCSPU. That is a terminal-based command line interface with live status displays. This capability is an important safety consideration. TCS can, for instance, be stopped completely by a failure in the NFS (Network File System). MCSPU was purposely made to not depend on NFS. It is fairly self-contained. So, in such a case the Engineering Interface can still be used to control the telescope.

Documents describing the MCSPU function are in the LBTO VCAN document system:

• T483s00196 : MCSPU Position Server Interface Control Document
• T483s00197 : Mount Control Program Architecture
• T483s00198 : Swing Arm Control Software
• T483s00199 : Engineering Interface for the Mount Control System Control Program

For a presentation on the MCSPU software see https://wiki.lbto.org/pub/Software/MCS/MCSPU_Control_Software.pdf