Dan, Dave

Today we rebuilt and restarted the OMC and OMC-SUS models to incorporate Livingston's changes to the ASC for the output mode cleaner.  These changes add outputs from the OMC model that pass ASC control signals to the OMC SUS (L,T,V,P,Y,R).

We've also incorporated a change from Livingston to the OMC master model (userapps/release/omc/common/omc.mdl) which adds a software trigger to the OMC length control signal.  This trigger shuts off the output to the HV PZT (OMC PZT2) when the HAM6 trigger is closed.  The input signal to this software trigger is the output of the PZT1_MON_DC channel; this acts as a readback for the shutter controller state.  The idea is that when the HAM6 shutter controller detects an input condition (light level above threshold), we should disable the length control signal to the OMC.  (Note that this change is somewhat redundant with the input trigger to the OMC length control signal, which enables the OMC LSC when the DCPD sum is above a threshold.)

Awkwardly, the output of PZT1_MON_DC is different between the two sites.  At H1, the PZT1_MON_DC readback out of the PZT driver box is -20V when the trigger is in the nominal/open state, and 0V when the trigger is tripped/closed.  At L1 it's apparently -5V when open and 0V when closed.  Furthermore, at H1 we calibrate the output of PZT1_MON_DC to reflect the voltage that is delivered to the PZT in the chamber: 10V in the open state, 0V in the closed.

The punchline is that I've flipped the polarity of the software trigger to work with the conditions at H1, and I've changed the threshold to be 5V instead of -3.9V.  This means the H1 version of the OMC master model is different from L1 - see the attached figure.  We'd like to understand why the output of the PZT1 DC monitor is different between the sites, but for now we'll need to remember that the master model here at H1 is slightly modified.  I have not committed these changes to the SVN.