Re: Encoder performance during recent sub-zero nights


Roland Christen
 

One is a Mach2, the other is a 1600 mount, which has the same encoders as the 1100. The readheads are all the same on all these mounts. The readheads have a laser diode that is used to read the scribe marks on the stainless steel ring. I'm guessing that at some low temperature the laser stops producing light and the readhead can't read the engravings. When that happens the signal light on the readhead turns red which indicates a fault.

For the 1100 and 1600 mounts, when this happens the mounts revert back to non-encoder operation. The mounts will operate normally like any non-encoder mount because the servo motors have their own shaft encoders that are used for tracking and positioning. You will lose the perfect tracking accuracy of the two axes along with the instant reversal capability in the Dec axis.

For the Mach2, with the present CP5 software a loss of encoder function will prevent the mount from being Homed and prevent it from being parked at the 5 park positions. The mount will still track and guide (at reduced accuracy) and can be slewed to objects and moved via the buttons, again at reduced accuracies. The home and park functions will fail since they are set points on the encoder rings. I am testing new CP5 software that will allow it to be parked at or very near the 5 park positions. Also the CP5 will indicate encoder non-operation with the indicator on the CP5 turning to amber. Basically the Mach2 will operate open loop as a non-encoder mount. We will release that software when it is fully tested.

Roland



-----Original Message-----
From: Patrick Spencer <patrick.spencer2@...>
To: main@ap-gto.groups.io
Sent: Sun, Feb 21, 2021 11:46 am
Subject: Re: [ap-gto] Encoder performance during recent sub-zero nights

That’s great to hear, thanks. It sounds like the zero Celsius rating is very conservative.
 
Were both mounts in your observatory Mach 2s, and if so, would there be any reason to expect different performance from the encoders used in the 1100GTO-AE?
 
Patrick Spencer
 
 
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Roland Christen via groups.io
Sent: Sunday, February 21, 2021 10:29 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Encoder performance during recent sub-zero nights
 
The mounts in my observatory performed normally at -10F. I monitored the encoders during that time and they worked fine. I don't know what the lowest temperature might be where they would stop working. I have two mounts in the observatory and both of them worked normally. No issues with the encoders on either mount.
 
Rolando
 
 
 
-----Original Message-----
From: Patrick Spencer <patrick.spencer2@...>
To: main@ap-gto.groups.io
Sent: Sun, Feb 21, 2021 9:53 am
Subject: [ap-gto] Encoder performance during recent sub-zero nights
Hi Roland, 

Did you have any issues with the encoder performance during any of the recent very cold nights? I know you use the standard temperature encoders, and it seems the recent arctic blast would have provided a good acid test for their limits.

Thanks,

Patrick Spencer

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics

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