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--[[User:Zjsimmons|Zjsimmons]] ([[User talk:Zjsimmons|talk]]) 22:51, 12 May 2014 (CDT)
Spent today trying different locking gain stage configurations, tried adding an additional stage to increase gain. Discovered error signal was not being properly added to DC offset, this seems to be corrected but two problems have cropped up:
# Integral gain has a relatively large DC offset, i guess this is not to be unexpected, but sort of fights the goal of zeroing in on the resonance point by adjusting the DC offset of the ramp and then turning on the gain, i.e. killing the ramp and adding the gained error signal to ramp DC offset. This can be suppressed but comes at the expense of gain.
# Piezo is resonating. Despite lowering the gain and lowering the roll-off point to very low frequency, the piezo is now oscillating. Can this be eliminated? Perhaps we need a lighter mirror set-up to raise the mechanical resonance frequency? It may be a good idea to get more piezos anyway, in case of failure.
--[[User:Zjsimmons|Zjsimmons]] ([[User talk:Zjsimmons|talk]]) 18:44, 9 May 2014 (CDT)
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