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Message ID: 1808     Entry time: Wed Jul 29 14:56:44 2009
Author: Jenne 
Type: Update 
Category: PEM 
Subject: MiniEarthquakes due to construction 

The construction people next door seem to be getting pretty excited about pounding things lately.  At my desk the floor was shaking like a mini-earthquake, and all of the accelerometers were pretty much railed. Clara has the Guralp box out right now, so the Guralp is unplugged, but the Ranger didn't seem to be railed.

This either (a) is part of the reason the MC is being wonky lately, or (b) has nothing whatsoever to do with it.  The MC watchdogs haven't been tripping all the time, so maybe this isn't a primary cause of the wonky-ness.

In looking at a many-days/months trend to see how far back this has been going, it looks like the accelerometers are hitting their rails pretty much all day every day.  This may be significantly hindering Clara's Wiener filtering work.  I think the gain on the accelerometer's controler panel is already set to 1, but if it's set to 10, we may want to reduce that.  Alternatively, we may want to put in attenuators just as the signal is entering the PEM ADCU, to help reduce the amount of rail-hitting that's going on. I don't remember this from a couple of months ago, so this may be a problem that will go away once the construction / landscaping is done next door.

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