The autoguider runs on its own cycle time of approximately one second duration and presents its error signals to the PE 3220 TCS computer via the CAMAC interface. The TNHZ task on the PE 3220 samples these errors ten times a second; the errors are multiplied by the ``open loop'' gains AGGRA and AGGDEC in order to scale the autoguider errors to the encoder errors to which they are then added. The gains AGGRA and AGGDEC are derived from the expression:
Gain = (sample time)/(autoguider update time)
Autoguider gains only need to be changed if there is a substantial alteration in the telescope response to small offsets.