However, the edge angle of limit switch of motor #3 has shifted by 1.7 degree (due to mechanical worn-out?). Software is using this edge to synchronize software angles and physical 1/4 plates angles. Therefore, transverse line S wave plate has been 1.7 degree off from supposed optimum ("supposed optimum" could also be ~1 degree off from physical optimum angle due to calibration limitation).
But, according to previous operation, we know that 1~2 degree offset on 1/4 plate will not significantly limit max target polarization.
The new limit switch position is saved to 1/4 plate control code. New setting are:
motor #0338 = plate #3 : Up Pos = -82.7 Degree; Down Pos = 7.3 Degree
Other motors are not changed
A copy of this log entry has been emailed to: jpchen, yqiang