HAPPEX slow controls |
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config
program. From the Unix prompt, type
config. A window like this will appear:![[Graphic: config window]](config.GIF)
The left section, marked "ADC Options", has a line of buttons for each ADC board (in the order in which they appear in the config file, which if there is any justice in the world is the order in which they appear in the crate, from left to right).
The "Debug Channel" buttons determine which ADC on the board has its integrator output appearing on the "INT OUT" LEMO connector on the ADC front panel. (Normally this doesn't matter.)
The "Integr. Gain" buttons determine whether the ADC board is operating in the low gain or high gain mode. (Normally low gain if not oversampling, high gain if oversampling.)
The DAC buttons control whether DAC noise is or is not added to the ADC input. (Normally on.)
Clicking these buttons actually doesn't do anything to the ADC immediately. To make a change, after clicking the appropriate buttons, you must click the "Send" button in the lower left hand corner. This gives you a chance to save yourself if you start to do something dumb.
The "P-Gun" section at the upper right displays settings for various devices associated with the polarized source. The first of these is the current value of the DAC used to control the Pockels cell HV offset (PITA DAC). You can change the DAC value by clicking the "PITA Set" button and entering the new value into the dialog box that comes up, or you can reset the DAC immediately to its nominal center value (2048 channels) by clicking the "PITA Reset" button. (Normally not something you need to worry about during running; reset the DAC before things like Mott or Moller measurements.) Below the PITA DAC are displayed the value of the voltage used to control the laser intensity asymmetry for the Hall C beam (the "TACO voltage"), the position of the upstream half wave plate which is used for slow helicity reversal (in or out), and the rotation angle of the downstream half wave plate which is used to reduce systematics associated with residual linear polarization of the laser beam. These last three devices are controlled through EPICS and may only be read out on this screen.
The "Feedback" section below that displays the name of the signal being used to do monitor beam asymmetries for feedback and the signal being used to normalize the monitor, if any, the length of a minirun, and the asymmetry value to cut on. You can change the minirun length or asymmetry cut by clicking the "Set Minirun" or "Set Cut" button and entering the new value into the dialog box that comes up. This can be done only between runs. Normally the monitor is bcm1, normalized by -none-, minirun length is on the order of 25000 pairs (depending on beam noise), and the asymmetry cut is large enough to get cuts pretty infrequently.
The "Oversampling" section below that displays the current oversampling factor. You can change the oversampling factor by clicking the "Set" button and entering the new value into the dialog box that comes up. This can be done only between runs. Normally the oversampling factor is 1 (meaning oversampling is off) or sometimes 4.
The "Modulation" section at bottom right displays the status of the beam modulation server and client. You can turn the modulation client on or off by clicking the button. Normally during HAPPEX production running the client and server both are on; during tuning and non-production running the client normally is off and the server can be off or on.
Clicking the "Quit" button will make config go away.
You can start or stop config at any time,
regardless of the state of RunControl. None of the
parameters controlled by config will be changed by
starting or stopping the program. It is recommended that you leave
config running while taking HAPPEX production data (and
look at it once in a while!)