Taking a LED run if beam is projected OFF for one hour (quick how to)

do not change HV, keep using production HV
reset the DAQ to the "coin_vld" configuration
ssh to cdaq machine as hccoda user. Navigate to cd /home/hccoda/scripts/VLD/bryan You will run the script "vld_various_DAC.sh" in this window shortly (don't star that script yet).
start a CODA run with ps2=0, all other prescale at -1 Label this run as LED-production various DAC
Execute the script ./vld_various_DAC.sh
When the script is going, the data rate should be about 200 Hz (give it +/- 100 Hz as the parameters are changed). The script will run until it exit and return you to the prompt. This should take about 30 to 45 min. End the run.
Email jroche@jlab.org to let her know you took that run. You're done! Thanks a bunch.

Run Coin Daq VLD Configuration

follow the daq instructions here:https://hallcweb.jlab.org/wiki/index.php/Hall_C_DAQ#If_the_CODA_vnc_session_disappeared_and_.27go_coin_daq.27_doesn.27t_work
Start the daq in Coin mode following the instructions above
In the Run Control GUI select the coda configuration "coin_vld"
Start a run with ps2=0

ssh to cdaq machine as hccoda user. Navigate to cd /home/hccoda/scripts/VLD/bryan
Make sure to start the run BEFORE starting the LED scripts, and verify the event rate=0
Execute the script ./loop_test.sh When the script is going, the data rate should be about 200 Hz.
FAQ: if something crashes or an LED gets stuck on, then run ./turn_them_off.sh to cycle through and disable all channels.

By default the DAC=45 , the pulse width=20ns , the pulse rate = 14.kHz. But this can be tweaked as explained below.
To change the DAC, open "loop_test.sh" and change the 45 to the new desired DAC in line 23 "bash vld_square_pulse_sr.sh 10 45 $j" One expect that lowering the DAC setting by 2 digit lowers the signal by a factor of two. The DAC can be anything between 0 and 63. We find that with the pulse width of 20 ns and cosmic HV, a DAC setting of 55 saturates many of the FADCs.
To change the rate open "vld_calibration_test_args.sh" and line 41 "PULSER SETTING=" to the desired pulse rate
vme5VLD13 is column3 0,1 and 2. vme5VLD14 is for columns 3,4 and 5. and so on
connector list 100 is for the lower half of the first column, 101 is for the top half of the first column, and 102 is for the bottom half of the first column. and so on.
The channel list gives the 16 pmts of the one-half of a column starting from the lower row.