Controlling the platform height


platform motions:
tiedowns,distomats use
tietrk command
tiepos (temp) command
tieposoff (inches)   command.

Platform motions:

Tiedowns, distomats used to control height:

    We use the tiedowns to try and keep the platform at the correct height: 1256.22 feet.
The procedure is:

The tietrk command

  We normally run the tietrk command. This will:

Problems with this method occur when:

    In this case letting the tietrk program continue to run will tilt the platform even more than normal.. this can change the pointing by 1 or 2 arcminutes...

The tiepos  (temp)  command

    This will move the tiedowns to a fixed position given the input temperature. eg:

The tieposoff (inches) command

    This command will move the tiedown the requested number of inches from where it is currently at. eg:

When to use tieposoff:

Once you get sufficient tension in the cables (say > 6 kips) you can switch back to tietrk...
But beware.. when the dome is at a high za and passes near a tiedown, you will again loose tension

<- page up