Robert Michaels, rom@jlab.org, Jefferson Lab Hall A, updated Jan 2003

Hey Bryan, copy this, modify it, and we'll relink it, etc.

To run the parity DAQ login to adaql1 as the apar account. Normally it will be available on the adaqs2 monitor where we launch all the DAQs during Spin Duality, and you must simply press "StartRun" and "EndRun" buttons.

The password for apar is available from the run coordinator. If you start from scratch, run "rcServer" interactively from a window logged into adaql1. Make sure the VME crate is up. This crate should be available in the "components" screen, you can "telnet halldaq6" and see if its up. If not, you can reboot the crate in the middle room (see the big sign). Next, run "runcontrol" and select the "sduality" configuration which is presumably the first choice. Download and StartRun.

Feedback to control the helicity correlated charge asymmetry runs automatically from Parity DAQ.   Thanks to J. Grames, B. Moffit, A. Vacheret, B. Bevins, P. Chevstov

TURNING ON and OFF the FEEDBACK

To turn on or off feedback script, login to an adaq linux box like adaql1 as ``adaq'' and execute one of the following. NOTE, this only turns on/off the script called by Parity DAQ. If you turn it off, you can still interact with the EPICS Gui for Charge Asymmetry control.

•         feedback on
•         feedback off

The following procedures can check if feedback is working and can measure the charge asymmetry.  

• You can see the info get updated in the EPICS Gui for Charge Asymmetry Feedback control.   Periodically a new value of Qasy, etc, gets written.   Warning, the time stamp is typically shifted.
• Execute the command ``chkfeedback'' from the adaq account on Linux box like adaql1 to print out recent results. You can also ``chkfeedback s'' for spectrometer DAQ results.
• To measure the asymmetry ?   The ``do nothing'' method is to look at end-of-run halog entries, but these are notoriously wrong if the beam is tripping frequently.   You can also run ``pan'' or ``qasy'' codes to measure the charge asymmetry.

  The pan code is the best to use, see the web page about running parity analysis:   http://hallaweb.jlab.org/equipment/daq/pan.html.

  The ``qasy'' code uses spectrometer DAQ scalers -- see   http://hallaweb.jlab.org/equipment/daq/qasy.html.

• Feedback does nothing ?   Maybe the server crashed or MCC forgot to turn something on.   Or it is ``disabled'' in the ``Helicity Correl. Feedback Ctrl'' EPICS Gui.   It's a good idea to periodically measure the asymmetry, see above.
• Wrong slope of Asymmetry versus Set-Point can lead to divergence.