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Entry  Mon May 28 17:36:58 2018, awade, DailyProgress, FSS, Fixing FSS binary under voltage issue 
    Reply  Thu May 31 14:17:42 2018, awade, DailyProgress, FSS, Fixing FSS binary under voltage issue 
       Reply  Tue Jun 5 16:35:54 2018, awade, DailyProgress, FSS, Monitor channels overdrawing current in output buffers 
Message ID: 2192     Entry time: Mon May 28 17:36:58 2018     Reply to this: 2193
Author: awade 
Type: DailyProgress 
Category: FSS 
Subject: Fixing FSS binary under voltage issue 

Autolockers were not catching the resonances again. It turns out I had unplugged the excitation to the FSS acromag controller box that engages the binary channels.  It had been plugged back in but often fails to activate the logic because it is still being powered from a 5 V plug pack.

Decided it was time to make the switch to 9V. I installed some voltage dividers to set the excitation out to the FSS interfaces to 4.9 V with a low voltage of 0.66 V maximum (unpowered).  See PSL:2058 for the wiring, I used option D with R1 = 820 Ω  and R2 = 680 Ω.  The new wiring was tested to check the voltages were right, so I don't fry the FSS interface box again.  I also made some changes to the soft binary channels in the acromag IOC: the front medm panel Test1 and Test2 switches are now flipped (NOT operation) so they make sense from the users point of view.  Before the logic was inverted so turning TEST1 off actually activated this path in the circuit.

I also noted down the channels off the ADC card that picks off the monitors from the FSS D25 connector.  This should reduce the number of front panel BNCs as it can all be routed inside the Acromag interface controller box. These have remapped from Aidan's acromag crate into the FSS interface controller box.

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