Note: there should be two GUIs seen on the VPD monitor (slow controls station) in the control room.
One of these is the standard VPD HV GUI. The other is a small one with 4 buttons on it. This GUI is only needed for the VPD HV gain scan - it
is not to remain available after the new gains have been set!

If the small GUI is not running, open a terminal window on sc5 and enter 'upvpd_settings'

At this point, you are ready to collect the VPD HV gain data.......................

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...at the sc5.starp station, there are two GUIs on the upVPD monitor:

"large GUI" shows all the channel values, and where one powers them on/off...
"small GUI" selects between different gain sets A, B, C, & default...

start with the VPD HV *off*

once there is a decent non-VPD-based trigger and stable beam:

1. on small GUI, click "! upVPD HV A" button
2. on large GUI, click in lower left corner to power on upVPD HV
3. wait until all channels are "green" (~20 sec).
4. make sure the values (upper left corner of large GUI,
     leftmost column) are as expected
5. wait ~1min for PMTs to settle (or take some other test run)
6. start run: TRG+DAQ+TOF only, 300k events.
     use string "upVPD HV A" in the shiftlog entry
7. power off HV (large GUI lower left corner)
8. wait until channels reach 0 (~20 sec)

9. on small GUI, click "! upVPD HV B" button
10. on large GUI, click in lower left corner to power on upVPD HV
11. wait until all channels are "green" (~20 sec).
12. make sure the values (upper left corner of large GUI,
     leftmost column) are as expected
13. wait ~1min for PMTs to settle (or take some other test run)
14. start run: TRG+DAQ+TOF only, 300k events.
     use string "upVPD HV B" in the shiftlog entry
15. power off HV (large GUI lower left corner)

16. on small GUI, click "! upVPD HV C" button
17. on large GUI, click in lower left corner to power on upVPD HV
18. wait until all channels are "green" (~20 sec).
19. make sure the values (upper left corner of large GUI,
     leftmost column) are as expected
20. wait ~1min for PMTs to settle (or take some other test run)
21. start run: TRG+DAQ+TOF only, 300k events.
     use string "upVPD HV C" in the shiftlog entry
22. power off HV (large GUI lower left corner)

23. on small GUI, click "! DEFAULT" button.
24. power on the VPD HV. 

That's it!

Do not use the small GUI anymore. In fact, feel free to close it!

At this point, I will get the data from HPSS, calculate the new gains, and then upload them to sc5. 

make sure the shift log says which gain set (A, B, or C) was used for a given run