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Entry  Thu Jul 21 15:03:13 2016, varun, Update, CDS, DAFI Update festatus.pngmatrices.png
    Reply  Mon Aug 1 20:09:37 2016, rana, Update, CDS, DAFI Update 
Message ID: 12361     Entry time: Mon Aug 1 20:09:37 2016     In reply to: 12321
Author: rana 
Type: Update 
Category: CDS 
Subject: DAFI Update 

I found the DAFI screen as a button inside of the LSC screen - I think its more logically found from the sitemap, so I'll move it into there as well.

Quote:

1) I have added the status summary of the DAFI block to the main FE status overview screen in the c1lsc cloumn. (attachment 1)

2) I have edited all the kissel matrix buttons appropriately, and given them appropriate lables. (attachment 2)

Gautam and I noticed a 60 Hz + harmonics hum which comes from the DAFI. Its the noisiest thing in the control room. It goes away when we unplug the fiber coming into the control room FiBox receiver, so its not a ground loop on this end. Probably a ground loop at the LSC rack.

Upon further investigation we notice that the Fibox at the LSC rack had its gain turned all the way up to +70 dB. This seemed too much, we reduced it to ~20 (?) so that we could use more of the DAC range.  Also, it is powered by a AC/DC converter plugged in to the LSC rack power strip. We cannot use this for a permanent install - must power the FiBox using the same power supplies as are used for the LSC electronics. Probably we'll have to make a little box that takes the fused rack power of 15 V and turns it into +12 V with a regulator (max current of 0.15 A). Making sure that the FiBox doesn't pollute the rest of the LSC stuff with its nasty internal DC-DC converters.

We also put a high pass in the output filter banks of DAFI. For the PEM channels we put in a 60 Hz comb. WE then routed the Y-end Guralp in through the boxes and out the output, mostly bypassing the frequency shifting and AGC. It seems that there is still a problem with GUR2.

Does anyone know which one is GUR1 and which one is GUR2? I don't remember the result of the Guralp cable switching adventures - maybe Koji or Steve does. According to the trend it was totally dead before March and in March it became alive enough for us to see ~30 ADC counts of action, so way smaller than GUR111 or GUR snoopy or whatever its called.

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