Re: Mach1 and GTOCP4 Yellow Light

Christopher Erickson

There is also some mysterious limits function in the CP4 that I have encountered in the past that I don't yet fully understand when using the CP4 and just the hand controller. It might manifest in other control scenarios as well. Basically, one day my Mach1 with CP4 wouldn't slew very far to the East (or West. I forget.) before the power light would go yellow and not let me slew farther. This was on a solid 13.6V 10A power supply. No hanging cables or other mechanical snags or problems. Cycling CP4 power got the red light back but as soon as I would try to slew into the "forbidden zone" the light would go yellow again. The mount was finding things in the sky everywhere else just fine and time/date/location/TZ info in the hand controller all looked fine. I tried a couple of "resume from Park X" procedures and suddenly the problem vanished and I could not duplicate it. I suspect that some safety limit variable was out of sync in the CP4, but I was unable to reproduce the problem to study it.

It has resurfaced about every other month or so on my Mach1/CP4 and the solution seems to be to do one or more CP4 power cycles and "Resume from Park X" procedures to get whatever variables inside the CP4 that are managing safety slews resynchronized with the rest of the CP4 code.

I shared this info with the AP CP4 programmer but I didn't hear back if he was able to reproduce the problem and/or get it figured out and fixed.

And of course there is always the chance that somehow I was unknowingly causing the problem and there isn't a mystery horizon limit bug in the current CP4 code.  

I hope this helps.


On Tue, Jul 7, 2020 at 10:41 AM uncarollo2 <chris1011@...> via <> wrote:

Make sure you have enough voltage from your battery or power supply, and that you have nothing else running off that supply. Make sure that your cable from the power source is as short as possible. Long cables lose a lot of voltage between supply and the mount controller.


-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
Sent: Tue, Jul 7, 2020 3:03 pm
Subject: [ap-gto] Mach1 and GTOCP4 Yellow Light

This started a week ago when I would suddenly get a Yellow warning light with a random slew when connecting the mount with the SGP. My first thought was that the control unit has condensated again but I was wrong and it turned out to be bone dry. Next I tried to fiddle the power and the Y cable and that helped and the next few days were fine. Last night the mount had violently slewed again so my I’m thinking now that I have a faulty cable.

I ordered both new cables but I am wondering now is there anything else I should check before changing those cables tomorrow before a clear night again?

- Mikko

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