Description | Save/Restore Configs | Printing | Advance

Description

Due to temperature dependent hardware drifts, the phase of some PEP II stations changes diurnally.  Power balance feedback loops can work to keep the relative phase of two given stations constant.  The loop uses a given station as the 'Reference station'.  The Feedback then controls the 'base phase' (L/HRXX:STN:PHASE:CALC.C) of the station under control to keep the relative power of the two stations at a fixed ratio.  These EPICS based loops can be controlled from the Power Balance Loop EPICS panel.

The following checks are performed before the feedback changes the base phase of the station under control.

• On Initialization (change of FBCK State), FBCKOut will be set equal to BasePhase.
• Feedback State needs to be ON, if not FBCK State will be purple to indicate it is selected OFF
  and the Status will be red to indicate Feedback is not running.
• Beam current needs be over (user selectable) threshold, if it is not the Current Threshold interlock will be
  red to indicate the problem and the Status will be red to indicate Feedback is not running.
• Reference station and station under control needs to be ON_CW, if this interlock is not true then the Station to Track select/interlock will be
  red to indicate the problem and the Status will be red to indicate Feedback is not running.
• Reference station and station under control cannot be the same (HR8-1 cannot Track HR8-1) if this interlock is not true then the Station to
  Track select/interlock will be red to indicate the problem and the Status will be red to indicate Feedback is not running..
• Measured Power Ratio is assoctiated a alarm status which will turn yellow or red depending if the Power Ratio Setpoint and the Measured Power Ratio differ by 5% and 10% respectfully

If the feedback is active, the calculation of the new base phase goes as follows:

If KlysFWRDPower is greater than (Reference KlysFWRDPower * Power Ratio* 0.001)
    then
        FBCKOut = previous FBCKOut - StepSize
   else
         FBCKOut = previous FBCKOut + StepSize

Save/Restore Configs

• LER Configs
• HER Configs

* NOTE: Pepii Archiver and SLC History Buffer PV names are different!

	Pepii Archiver	SLC History Buffer
Feedback Actuator	$(STN):STN:PHASE:CALC.C	$(STN):STN:PHASE:CALC.C
Klys Fwd Power	$(STN):KLYSOUTFRWD:POWER	$(STN):KLYSOUTFRWD:POWER
Power Ratio Setpoint*	RB00:$(RING):$(STN):AO:RATIO	RB00:LR42:RATIO
Klys Fwd Power*	RB00:$(RING):$(STN):AO:STEP	RB00:LR42:STEP

Printing

There are two methods to print the Power Balance display.

• Print Button on the Display
      Bring up a printer selection list, preforms a screen grab seconds later and send output to selected printer. This method also corrects orientaion for Elogs.
• Middle Mouse Button dialog Print
      Bring up the Dialog below. Users are able to select customize print options.
      NOTE: When printing to Elogs, Select "Portrait" Orientation, so Elogs will not rotate image.

Advance

• What to edit in this Application in order to add additional RF Stations
  • Items to edit
    • db templete file: PowerBalance_all.template
    • Display file: rfb_main.edl
    • ChannelWatcher for bumpless reboot
                  $CD_SOFT/dev/confsys/CW.RB00.?ER   ?= Ring
    • Config Save/Restore PV List
      • Stations added to HER.pvlist and LER.pvlist
            /a/mccfs0/u1/pepii/ctrl/rfb00pep00/pvs/makepvslist.script
  • Reference Docs
    • Soft IOC Development @ SLAC
    • Channel Watcher
    • Dynamic Restore
    • IOC Console Access
• Database files
  • PowerBalance_all.db
  • PowerBalance_misc.db
  • PowerBalance_all.template
• Names
      <Appname >        =  rfbApp
       <LCmicroname>  =  RB00
       <nodename >        =  rfb00pep00