Amazingly fast response and about a dozen people identified the problem immediately:
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It's a simple fix.
The shim DAC driver board has a lock polarity switch that needs to be swapped.
I'll assume the magnet was brought back up in positive polarity. Varian/Agilent typically runs them up negative polarity.
No problem, just switch the position of SW2 and the system will lock & shim properly.
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We did in fact energize with positive polarity.
I pulled out the shim DAC driver board and found a toggle switch labelled "SW2". I flipped the switch and put the board back in.
Now I get a positive lock level and a stable lock with lockphase set at 180. Problem solved! Thanks to all who responded.
Neil
Received on Mon Jul 06 2015 - 09:38:51 MST