From: Larson, Rod
Sent: Monday, September 15, 2008 6:07 AM
To: Duemke, Roger
Subject: IBST Status
Roger,
Checked system today. Most all works ok. Had to flip the polarity of the y-axis accelerometer cuz Omar did not flip that when he flipped the y stroke.
Balanced servovalves and zeroed 3rd-stage spools.
 
System runs ok but exhibits typical 505 pump problem. These systems do not use much oil during tuning and setup. A 505 w/o a fine filter in a circulation loop is a dirt generator then and clogs Moog valves. You should get some Moog fine filters and send them here cuz they already need them. I had to run 1-2 volts of dither for about 2-3 minutes to get the valves to NOT drift like crazy.
 
Cannot get HP replacement power supply. HP no longer makes that particular PC nor the power supply. The only recourse we have is to ship one from a unit at MTS. If not, then we should buy a replacement here. It WILL require Robin to be here to install the 793 s/w. The customer will be unable to do that. I would recommend that I just go buy a new PC here so we can put it in. My corp card has a $15,000 limit for such things and I don't mind getting yelled at by the (*&($*&# in purchasing. It WILL save a $1,000 to buy one here, I think.
 
I have to put together some special waveforms for the acceptance tests. The pump is so small that we cannot get a full cycle out of it to make the performance curve. The 469D uses a ramp-up to get a smooth start, but that ramp-up uses too much oil. I can get some 1 and 2 cycle waveforms that make the right amplitude at the 1st peak w/o causing any unusual bangs on start-up. I am not 100% sure even that will make performance. We are really shy on velocity. No problem on stroke or acceleration.
 
BTW, when the stroke is >250 mm, then the calibration should be for 300 mm so we can get the actuator out of its cushions gently (can destroy specimen). So, the 250 mm cal on these actuators is actually dangerous to specimen health. I will instruct the customer to be very careful about that. If the actuator is in its cushions at +/-275 mm, turning on low pressure can generate about 2-3 g's when the actuator pops out of the cushion going to 250 mm. I can change the settings files so we have the extra stroke, but it doesn't help 100%  cuz the conditioners bottom out at 11 volts. However, we can limit the bump to about 1 g that way.
 
Tomorrow we have no electrical power; therefore, I had Robin arrange for a generator so we can at least train with the computers.
 
Let me know if you want me to buy a PC. I will probably call you in the morning (6am mpls time now...)
 
Rod