Moving the Swing Arms
Last update 30 April 2010 by John Hill
Changing the telescope swing arm configuration can be done using MCSPU or OSS. This latter one is much easier, however, it is advisable to keep the swing arms page on MCSPU open to monitor the process as well. This updated version emphasizes on using the OSS gui. The MCSPU command line procedure is preserved below.
Caution: This procedure covers moving the swing arms and rebalancing from a KNOWN balanced configuration. Before moving any swing arm with an UNKNOWN balance configuration, be sure the auxiliary drives are ENGAGED (beyond the scope of this procedure)
Moving the Swing Arms using OSS
Move to Zenith and Insert Stow Pins
1. Turn on HBS if it isn't already on.
2. Ready the Elevation axis if it isn't already ready.
3. Move the telescope to the zenith using MCS: click on Slew
with argument 90 degrees.
4. Engage (insert) stow pins. For that, on MCS bring up the Elevation sub-GUI and click on Stow Pins IN
for left and right.
5. Rest the AdSec shells. AOS > Rest
, or AdSec Control GUI > Rest
. Verify that the statuses in AOS and AdSec Control GUI are "Safe" and "Shell RIP" respectively.
Reconfigure the Swing Arms
6. On OSS, click on Swing Arms
either right or left to bring up the sub-GUIs. Both sub-GUIs can be started at the same time.
7. Turn the motor drive power supply on. For that, click on Motor Power On
on the Swing Arms sub-GUI, and wait a couple of seconds before power is completely on.
8. Click on Retract
depending on what configuration you need. The retracting/deploying process should take about 5 minutes per swing arm to complete.
You can click commands for multiple swing arms to queue them ahead. Note that only one swing arm at a time can move on each side of the telescope.
9. Once the configuration is done, turn off the motor power supply off on the swing arms sub-GUI by clicking on Motor Power Off.
Adjust the telescope balance
Be sure to verify the balance before you retract the stow pins.
10. Adjust the dynamic balance of the telescope. For that, go to the dynamic balance page on OSS.
10.1 Clear the errors of the pump drive line by clicking
Clear Error Y
.9.2 Do the dynamic balance by clicking
and monitor the process until the line of the accumulator shows a low value (below 20 Kg*m).For assistance, ask the telescope manager or engineering manager about it.
11. Verify that the telescope is still precisely at zenith (and not resting on the stow pins). If the telescope is resting on the EL stow pins, EL does not equal 90 (i.e. 89.5). Can use "elslewtohold 90 o" in mcspuDisplay to get off the stow pins. Verify that the elevation drive torques are normal (mcspuDisplay. Actual: +~40%, ServoError/rmsTrackErr: ~-40%).
12. Retract the stow pins.
13. Use the IIF GUI to update the instrument authorization for the new configuration and instrument.
14. If changing telescope sides, use the TCSGUI to stop PCS, select the new side, and restart PCS.
15. Check that primary mirrors, secondary mirrors and tertiary mirrors (as needed) are ready in the new configuration.
Moving the Swing Arms using MCSPU - This is the old version of the process using the engineering interface. (still valid though)
Start MCSPU as needed, and move the telescope to the zenith.
Turn on HBS if it isn't already on. Ready the Elevation axis if it isn't already ready.
Insert the stow pins.
From MCSPU, push the stow pins in.
Make sure the swing arm drives are not locked out.
The lockout key and reset button are in the upper right tree house.
Turn the motor drive power supply on
on MCSPU rsa
powerSA right on
powerSA left on
Select the Swing Arms you want to move.
There are 4 swing arms for each primary mirror:
Adaptive secondary (AdSec)
Prime Focus (PF)
Tertiary Mirror (TM)
Mirror Cover (MC)
You are most likely to need to move the Prime Focus swing arm. To select it, type the following command on MCSPU:
selectSA right pf
selectSA left pf
Now you can move the swing arm using the following commands on the MCSPU window;
retractSA right pf
this will start retracting the prime focus right swing arm.
deploySA left pf
this will deploy the prime focus left swing arm.
When you are done with your work at the swing arms, turn the motor drive power supply off
on MCSPU type
powerSA right off
powerSA left off
Be Sure to Get the Balance Adjusted BEFORE you retract the stow pins.
For that, on MCSPU go to the Dynamic Balance Page by typing
then clear the errors of the pump drive line by typing
then do the dynamic balance by typing
Check the elevation servos and verify that telescope is still precisely at zenith
Verify that the Elevation drive torques are nominal.
Retract the Stow Pins
Use the MCSPU, to push the stow pins out.
- 01 Jan 2010