Sean came from Richardson TX about ten days ago to start testing out the servo. After some quick initial success, we began to find some problems. The first problem was a velocity limit in el, fixed by reprogramming the motor controllers. The next problem was an oscillation in the position loop in Azimuth. After a couple of days of back and forth with Richardson, they were able to figure out that it was some arcane software lock, which was failing to recognize a hard-wired rate limit. The az appears to now go to a position reliably.
The next step is to tune the parameters, but I am not sure we can do that until I am happy with the balance, more investigation is needed.
The current headache is that we cannot get track beam mode working. This has been anticipated, since SPT had some major issues getting it to work. We seem to make tiny bits of progress every day, but it is slow going because the system is so complex. I spent, for instace, some quality time on the floor of the contiainer fine-tuning some resistors so we could get exacly 10 microsecond pulses. Not fun, but it did appear that we got one baby step closer. The telescope is at least following the scans, and we saw for the first time a basline polarbear scan, 15 degrees back and forth.
We are still not getting any replies from the ACU, so event though the telescope is moving, we would not be able to tell where it is moving without looking at it.
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