SECONDARY MIRROR CONTROLLER ERROR on the telescope status monitor? This may indicate the focus controller is confused. Try UIP> antenna /restart
Multiple difficulties at the same time? Scans won't start, the telescope doesn't move, the spectrometer is hung up, scans stop in the middle of integration, etc. Try UIP> antenna /restart
or UIP> antenna /restart /nosync
Do not press the reset button or power cycle the antenna computer unless you are certain a hard reset (powercycle) is needed. Further information here or here.
Tlength large? This is the angular distance between the dome and the telescope. It is small during normal operation so any significant value indicates a fault. A misalignment of 0.1° corresponds to tlength about 0.075. If tlength is positive, the telescope azimuth is smaller than the dome azimuth. The control system stops the telescope if tlength exceeds about 0.250.