Re: Setting RA/Dec Limits in a GTOCP4 on a 3600GTOPE?

Ray Gralak


You should give A-P a call or email for answers to this question.


-----Original Message-----
From: [] On Behalf Of Karsten Schindler
Sent: Tuesday, April 6, 2021 12:00 PM
Subject: [ap-gto] Setting RA/Dec Limits in a GTOCP4 on a 3600GTOPE?

Is it possible to define RA and Dec limits on the GTOCP4 controller side to limit the allowable slew range of a

I do not mean horizon and meridian software limits defined in APCC. I also do not mean the Limit Switch System /
ELS on the 3600GTO which provides "hard stops" on the RA axis.

I would like to limit the allowable slew range from the controller side to something that makes sense at our location
in the northern hemisphere, particularly in declination. Due to roll-off roof building constraints, our setup is sitting
pretty low above floor level. Would provide an additional layer of safety.

The PDF help file speaks about "home and limits for non-encoder mounts" and mentions explicetely the 3600GTO,
so I thought it might be possible to define such limits for mounts that have no absolute encoders (ours has a
precision encoder, PE, on the RA axis).

The APCC help file shows a Homing/Limits tab that is not accessible when a 3600GTO is connected. The ELS tab
lists a mechanical position (I assume servo / encoder derived), and allows to establish or go to a home position.
However, I do not see any way to program an RA or Dec limit into the controller.

Thanks for your feedback!


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