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Mark M. Ito, Thomas Jefferson National Accelerator Facility
12000 Jefferson Ave., Mail Stop 12H, Newport News, VA 23606
Email: marki@jlab.org, Office: (757)269-7175, Pager: (757)680-7175
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Mark Ito
December 5, 1996
CONTROLLING PMT HIGH VOLTAGES
Some useful information:
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HV will not be applied to a channel unless the appropriate mainframe is "on"
and the channel is "enabled".
Voltages are in volts, currents are in micro-amperes and time is in
seconds. E. g., ramp up rates are in V/s.
A "mainframe" is a physical crate of cards that holds up to 16 HV cards
numbered 0-15.
A "HV card" controls 12 channels, numbered 0-11.
A "group" is a collection of HV channels that can be enabled and
disabled with a single command. Each group has an index which is
defined in the file $APP/hvca/db/ecsc.grp (bmta.grp).
We are presently using two different computers to control HV for
historical reasons. cebafbe will control beam counter and tagger
channels and clas10 will control the time-of-flight and calorimeter
channels. The following instructions are for clas10 (with the
variations for cebafe shown in parentheses). The control will be
consolidated as soon as we have a chance.
There is a HV file which contains all HV control parameters and geographic
information: $APP/hvca/db/ecsc.dat (bmta.dat). The columns in this
file are:
channel label
group id
allow/disallow operator HV turn on: 1 for allow, 0 for disallow (not coded)
mainframe arcnet address
slot number
sub-module number: 02 for all PMT HV channels (as opposed to chamber HV)
channel number
demand voltage: in volts, signed
measured voltage dead zone: a significant change voltage
measured current dead zone: a significant change current
ramp up rate: unsigned
ramp down rate: unsigned
trip current: signed
software "maximum": in volts (not yet implemented)
To start the gui:
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Log into clas10 (cebafe) as clasrun (standard password).
Set the DISPLAY environment variable:
setenv DISPLAY your_x_terminal_name:0.0
Give the command:
hv
To exit the program:
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De-iconify the "medme" icon.
Open the menu "File".
Click on "Exit".
Description of Screens:
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Auxiliary screens are accessed by pushing the overlapping-squares-icon
buttons and choosing from the menu that appears.
To change a value place cursor in a "set" box, type in the desired
value and hit <return>. You must hit <return> to enter the value.
Main Screen
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HV/On and HV/Off buttons: turn mainframe on and off. When off the
"LED" is white, when on it is green.
Group Enable/Disable: Enables (green) or disables (red) an entire
group.
Save: Will save current values of the set and measured voltages and the
measured current.
Restore: Will initialize all values using those contained in the HV
file.
Alarms: Not yet implemented.
Links to Voltage/Current: Calls up screens that display measured and
set voltages and measured currents. The labels are those of the first
channel displayed on a page. Each page contains up to 24 channels.
Voltage/Current Screen
----------------------
Enable/Disable: Enables (green) or disables (red) an individual
channel. If a channel is enabled, a green "LED" turns on.
Set Voltage: field for inputing a new demand voltage. Must be a signed
number.
Voltage/Current: Same as "Links to Voltage/Current" on main screen.
Control Parameters: Calls up screens of the control parameters not
shown on the Voltage/Current screen.
Problems?
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name office pager home email
---- ------ ----- ---- -----
Mark Ito 7175 680-7175 249-4472 marki@jlab.org
Sasha Philips 5199 (202)994-8228 philips@gwis2.circ.gwu.edu