[Hallc_running] [EXTERNAL] Re: More on Prescale GUI

[Hyde, Charles E.]

Hello,
A couple small comments on Prescales
*Step 4 should really be before Step 3 in Ed's instructions/explanations
*The absolute bullet-proof procedure has
Step 7:  After start of run, look in the HCLOG Start-of-Run entry and open the file coda-flags.dat.  The actual prescale values for the run are at the bottom of the file.
:)

Sincerely,

Dr. Charles E. Hyde
Eminent Scholar and University Professor of Physics
Old Dominion University
Department of Physics
4600 Elkhorn Ave
Norfolk VA 23529
PS-II 2100J
1 (757) 683 5853
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.odu.edu_physics&d=DwIF-g&c=CJqEzB1piLOyyvZjb8YUQw&r=u5tNM-t17TvnEMN44CWm5qVyE415lk08NPqyR_N_lLM&m=vCaHmMjqoJ2L8Zid79nwZtydO09BiYZApgMHqx52y97kZrFmwroadPp6TU4w4HJL&s=1BqYfPjWW7fOhhbLTLsGxZgWWBXoiVA4qkut6BgWi2s&e= 




________________________________________
From: Hallc_running <hallc_running-bounces at jlab.org> on behalf of Edward R Kinney via Hallc_running <hallc_running at jlab.org>
Sent: Monday, July 21, 2025 1:36 PM
To: hallc_running at jlab.org
Subject: [Hallc_running] [EXTERNAL] More on Prescale GUI

EXTERNAL to ODU: This email is not from an ODU account. Do not click links or open attachments unless you recognize the sender and know the content is safe.
Hi Folks,

We still have some confusion about setting the prescale factors using the GUI. Hanjie contacted me and we need to be sure everyone understands how to use the GUI.


  1.  After a run is ended, if you wish to change a prescale factor, you may kill and restart the GUI if you wish; Hanjie believes this is unnecessary, but it won’t hurt.
  2.  In between runs you can change the prescale values or use set rate functions to determine which ps value you want and evaluate the trigger rate.
  3.  Recall you can either “prestart” then “go” manually or “start” which performs both “prestart” followed automatically by “go”. Hover the cursor over the coda buttons to make sure you know which is which. Normally we use “start” (>>). You should never begin the run with “go” without a “prestart.”
  4.  You must press SAVE, before starting or prestarting the run.
  5.  The scalers are disabled during “prestart” and won’t be enabled until the end of “Go”, so between “prestart”, CODA shows run “active” in green. There is no scaler readout, so the prescale GUI and the xscaler shows no rate; people may have interpreted this as the GUI being hung, but it’s actually not.
  6.  If you SAVE after prestarting, the ps values will not be read in by CODA, so if you did this, you’ll have to end the run and begin the process again.

You can find a lot of useful DAQ info at  https://hallcweb.jlab.org/wiki/index.php?title=Hall_C_DAQ <https://hallcweb.jlab.org/wiki/index.php?title=Hall_C_DAQ >. Don’t hesitate to ask the RC if you have a question!

Sincerely,
Ed, your RC!