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Message ID: 897     Entry time: Fri Aug 29 11:01:49 2008
Author: josephb 
Type: Configuration 
Category: Computers 
Subject: Attempt to change a channel gain in ICS-110B 
As noted earlier by Rana, I was playing around with the /cvs/cds/caltech/chans/daq/C1IOOF.ini file with help from Rob. I had made a backup before hand and saved it as C1IOOF.ini.Aug-28-2008. (I have since been informed that C1IOOF.ini.082808 would have been prefered as a name).

We had been trying to up the gain in the C1: PSL-ISS_INMONPD_F in order to do a very low power PMC sweep, in an attempt to get clean modes for fitting. Initially we pressed the reconfig button on the C0DAQ_DETAIL screen, but all that seemed to do was change the Config File CRC. We proceeded to reboot fb40m remotely. However, any change to the ini file (even an extra space at the end of the file) caused a 0x2000 status for C1IOVME16k on the C0DAQ_DETAIL screen. At the time I presumed it was comparing the CRC of the ini-file to something else.

Digging around on in Alex's webspace at http://www.ligo.caltech.edu/~aivanov/ , I found the NDS Access page, which indicated that 0x2000 was a conflict between the front-end and frame builder .ini files.

"There is also status bit 0x2000 which gets added when the DCU configuration is different in front-end and frame builder. That is you can change and .ini file an then reload DAQ configuration with Epics button, which reconfigures the front-end, but leaves frame builders with invalid old configuration. They will detect this change and set the status to 0x2000 to indicate this condition. You will have to restart frame builders to pick up new .ini file and set status back to zero for the affected DCU."

It was when I was going to try reseting the c1iovme via the C0DAQ_RFMNETOWRK medm screen that we realized the EPICS controls were not responding properly. The .ini file was returned to its original form, and mass reboots commenced.
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