Re: PEM Curve vs. Worm Gear Position


Thanks Bill. I found this under a PEM topic and it was just the technical rationale I was looking for. Just happened to find it after posting:

And here are some more great and exclusive features of AP electronics that AP doesn't bother to mention in their literature or specifications:
A. Power-loss detection and data preservation. AP servo controllers can detect when power has been lost/cut and by using a special "brownout protection circuit" they quickly save the worm gear angle, worm wheel angle and spur gear train rotation position to NVRAM. That way the controllers know exactly where the spur and worm gears and wheels are positioned when power is restored. This is how the PEM data is kept in sync and how the controller already knows where the mount is pointed when it is powered up. Of course if a user is doing portable setups and/or the clutches are opened, the controller won't know if the OTA is pointing to stuff accurately or not. A single Calibration/Sync will fix that, when needed. This is also a great feature at star parties and outreach events. If someone kicks out your power connection, all you have to do is restore power, initialize the CP1/2/3/4 servo controller (automatic with the AP hand controller) and do another GOTO the object to get it back in the center of the eyepiece and track it 

Thanks for the quick answers - 

Bill K.

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