Installation Plan

This evolving document is a discussion of the items that will be installed and the telescope / observatory modifications needed for the new TCS.

Feb 21 2008: A decision has been made that the conversion effort will be done in a non-reversible manner (i.e. no going back) starting on the July 14th summer shutdown. During this period the hour angle, declination, focus, mirror cover opener, and dome azimuth will be installed and running before on-site observers are allowed. Slit operation and weather will follow at a later date.

Boxes

There will be five boxes, one tower, and one long conduit installed. To follow this discussion print out a copy of the Cable diagram. The following discussion is roughly in the order of installation.

Control Box

The control box has been mounted in the computer room. on the wall adjacent to window. Here is a drawing. A cable with a line plug comes out of the box and will have to be connected to the UPS. A cable (C22) to the UPS for the "UPS GOOD" signal is also needed. A keyed power switch will be installed to turn off power. Ethernet connection to the network is also needed.

The cables will pass down from the box into a wireway on the floor. A strain relief of nature yet to be decided will be installed on the wall. One possibility is a piece of unistrut mounted on the wall with long bolt to which coils of the unused cables can be hung. The cover of the floor wireway will have to be cut to allow access to the cables.

Hour Angle

Ripout: All the present motors, clutches, differentials, gears and encoders will be removed from the HA drive plate. Wires can be cut as the items will not be re-used. The only thing left will be, of course, the worm. Unused cables will be removed.

Install: A belt pulley will be installed on the right of the worm. This pulley has been machined to the proper diameter. The motor mount will be mounted using an adapter plate into the existing holes below the right side of the gear.

The position encoder will be mounted directly off the left end of the worm drive. An adapter plate will be made to so the encoder mount can mount in the existing screws and be at the correct location. It is coupled to the worm using a xxx coupler.

A piece of unistrut will be mounted on the flanges on the drive cabin using clamps. East and west limit switches will be mounted on sliders. These contain two levels (regular and failsafe). Shorter pieces of unistrut will be mounted with molly screws in the existing one inch diameter holes in the worm gear. A dog will be mounted on this unistrut to set the activation point. It is an MDM responsibility to set this point.

??A magnetic strip will be cemented on half the worm gear. A Hall effect sensor mounted on the unistrut will act as the home flag. This will be used to resolve the ambiguity in the encoder index mark to determine the exact home position.

There are four cables: C1-limits, C2-encoder, C3-halls, and C4-motor that will pass through the base of the telescope. A small junction box maybe installed to consolidate the home flag and limit connections. A xx-diameter hole will be drilled to accommodate these cables. This hole must also accommodate cables going to declination and beyond. The cables will then run into the pit, and through the pipes going into the control room.

West Box and Primary Mirror Cover

Ripout: The existing west box will be removed. The paddle will be disconnected and possibly used later. Obsolete cables will be removed.

Install: New receptacles will be installed to supply 117 v.a.c. power that is used by instruments.

A new box will be installed in the same location. The new box will do the following:

To install the mirror cover opener.

There are four cables: C17-mirror cover, C18-mirror cover power, C19-tilt, C23-tel temp that will be dressed around the primary, down the telescope center tube, out the HA cage and to the Control Box.

East Box and Dome Azimuth

Ripout:The the two existing Dome control boxes will be removed. The two existing dome azimuth motors will be replaced. The three vertical BX going upward from the box. The vertical conduit from the floor will be preserved as it has 117 v.a.c. power.

Install: A new box will be installed. The box will contain:

The 117 volt floor controls can go through the existing conduit on the bottom. The control cables will go through the semi circular conduit to the control box.

For the dome azimuth drive:

The three phase drive will be supplied by the normal 117 v.ac. mains power (non-UPS);this is already present in the conduit to the existing boxes. Great care in the wiring of this drive to the motors is needed as it can radiate a lot of unwanted noise. Cables C9-encoder and C12-encoder will be routed through the semi-circular conduit to the control box.

Semi Circular Conduit

Install: A run of 1-1/2 inch IMT conduit will be installed going from near the slip rings on the upper east side of the dome, running along the top of dome wall to the south where there will be a sweep 90 and another run down to the cable inlet to the control room. A junction box will be installed at the top end. It isn't clear what to do at the bottom end. How is this conduit grounded?

North Box

Ripout: The present North relay box will be removed. The only thing to be salvaged is the control wire that controls the motion of the floor. A temporary control box will have to fabricated for temporary use. The wire from the floor switch can be cut. All unused cables will be removed.

Install: A new much smaller box will be installed at some yet to be specified location. One possibility is on the floor itself at which point flexible conduit will have to be installed.

This box will have:

The cable C27-interlocks will run down the large floor channel southward to the control room.

Declination

Ripout: All the present motors, clutches, gears and encoders will be removed from the Declination drive plate. All old cables will be removed from the central cable run.

Install:

The location of the motor holder has yet to be determined. There are four wires (C5-limits, C6-encoder, C7-Halls, and C8- motor) that will be dressed down through the axis and out through the hour angle gear and onward to the Control Box.

Focus

Ripout: The existing SloSyn drive motor. Keep the limits switches. All present cables.

Install:

The motor mount will have to be designed and fabricated when the motor is removed. Three cables (C12 - limits, C13- encoder, C14 - motor) will have to be dressed down the telescope sides, down the center tube of the telescope, through the hole in the hour angle cabin and finally to the control box.

Pier Interlock

Install: A stainless steel cable will be installed from the top of West pier down to the bottom where it will be connected to a pull limit switch. The top mounting will look like ???. The bottom mounting will look like this. Pulleys may be used if needed. A turnbuckle tightner and other rigging has been purchased.

The limit switch will connect to the North box where it will then go to the control box. A second pull limit switch has been purchased for the East side, but it isn't clear whether this need to be installed.

Temperature sensors

Install: Temperature sensors (AD590s) will be installed at various parts of the telescope these will be wired to the West box and then connected to the Control Box via cable C25.

At least one of the sensors will be mounted in a hole drilled in the large tubes going up to the secondary. The sensor will be covered with insulation so it will respond to the metal temperature. Another will be placed near the primary mirror.

Note the following will be installed after "local" observers have returned. The following will be needed for "remote" observers.

Slit Opener

This one is really vague since I don't know how the slit opener works.

The following things will be done.

The C15-RS485 cable will be routed through the semi-circular conduit to the control room.

One cable (cable C15) is then needed to go to the control box.

Weather station

I propose installing a tower at the South west corner of the building. See the location on the Dome sketch or in this silly graphic. The tower will a triangular radio tower set in a small concrete pier similar to that shown here. It will be twenty feet high which puts it about 11 feet above the pony wall. The top will have a lightning rod connected to the ground lead that is already in place. The weather instruments will be placed about a foot below on a horizontal cross spar. While this is not ideal weather indicating location, it should be easy to erect, service and cable. The following things have to be done:
MDM index