Appendix A2 - Recovering From Unexpected Memory Upsets - RESEARCH CONCEPTS RC2000C Manual

70 RC2000C Polar Tracking Antenna Controller Appendix A2 Recovering Memory Upsets

Appendix A2 - Recovering From Unexpected Memory Upsets

The key to restoring the non-volatile memory is getting the azimuth and elevation limits and position
counts right. The position counts are initialized to 30 when the east and down limits are set. If the
antenna can be unambiguously placed at the east and down limits, non-volatile memory can be restored
quite easily. It is probably a good idea to use a punch or a waterproof magic marker to mark the antenna
and mount assembly so that the east and down limit positions can be identified. In addition, it may useful
to identify and mark other places on the mount where slippage could occur. This would allow the mount
to be restored to its original configuration.
If the contents of non-volatile memory are recorded as outlined in steps 1-4 above, recovery from an
unexpected memory upset can be readily accomplished. If the memory is corrupted, the antenna can be
moved (in LIMITS mode) to the east and down limit with the aid of an assistant stationed at the antenna.
Next, steps 7-9 can be used to restore the contents of non-volatile memory.
Note that the procedure for restoring non-volatile memory only works if the count characteristics of the
actuators are not changed. If the actuator count characteristics are changed, the count values that
correspond to the west and up limit will change, as will the positions of all of the satellites.
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