TOFp System Procedure:
TOFp High Voltage On or Off


   Description:
This is the procedure how to turn on or off the High Voltage applied in the TOFp tray. There are 41 slat assemblies inside the tray. Their HV is provided by the "HVSys" System, which is a custom system for TOFp and hence uses custom software for control and monitoring.
   Related Documentation:
  1. TOFp Glossary
  2. HVSys Users Manual
   Requirements:
  1. Approval of TOFp Group.
  2. Access to STAR Control Room.
  3. STAR Shift Crew Training.
  4. Approval of Shift Leader.
   Procedure:
Screenshots: slowcontrols.jpg,  tof_top.jpg,  tofphv.jpg,  tofrhv.jpg
  1. Sit in front of the TOFp Control PC, and open a terminal window. Then ssh to the machine tofpdaq.star (the password is posted at the TOFp Station in the control room).
  2. Check whether the monitoring program is running. Enter: 
    hvmon status
     if it is running, stop the monitoring program by entering: 
    hvmon stop


    3. TOFp HV OFF

  3. To turn TOFp HV off, enter:

    4. tofhv_OFF


    TOFp HV ON

  4. To turn TOFp HV on, enter:
    5. tofhv_ON
  5. Then restart the monitoring program by entering 
    hvmon start
  6. Wait 45 seconds and then check the status of the monitoring program by entering 
    hvmon status
  7. Go to the slow controls terminal and click on TOF->TOFpHV->P (see slowcontrols.jpg)
    ... or ...
    open a unix terminal on sc3.starp as user "sysuser" and start the TOF alarm handler "tof_top" (see tof_top.jpg) and click on "TOFp Monitor" (see tofphv.jpg)
  8. Watch the unix timestamp update (should do so every 10 minutes) and check that the Voltage on Branch 0 is about 200V (usually somewhere between 199-201V). All HV read and set values should be non-zero. An unfortunate feature of the HV readout causes losses of bits in the communication between the power supply and the cells. This may result in "overflowing" readback values which appear at roughly 2400V. These appear randomly and should typically dissappear after subsequent readout cycles. If a channel remains below 1200V for a longer period (more than 1hr) it might have died and the TOFp detector experts should be contacted (tofp@physics.rice.edu).
   Testing:
   Completion:
  1. Contact TOFp Control with any end-of-procedure comments that are necessary. Was this procedure successful? Is this documenation understandable and complete?