Re: Using the GTO keypad with the Mach2

Woody Schlom <woody@...>


Yeah, I have one of these too. They’re great – and so simple once you’ve converted all your power cables over to PP.


From: ap-gto@... <ap-gto@...>
Sent: Thursday, September 19, 2019 1:49 PM
To: ap-gto@...
Subject: Re: Fwd: [ap-gto] Using the GTO keypad with the Mach2


I purchased the A-P Online Power meter some time ago

and have found it very useful.for assessing current draw under varying loads, balancing the scope, evaluating if something is binding somewhere, e.g. cable drag, remaining battery capacity.


---In ap-gto@..., <theresamarie11@...> wrote :

Rolando, thank you again for all of the great information. You should put some of this in your specification (just a suggestion). I’ll be able to monitor it once I have a chance to connect the Mach2 to a battery since I have a shunt installed to monitor draw. I’ve never noticed the spikiness of the dew controller, but do know that they're pulse width modulated (not clear on frequency) and I currently use a simple 5A “brick” supply with my current setup that supplies everything (mount, heaters, camera cooler, focuser, USB hub, etc) when running at home. With the Mach2 and supplied 24V power, It’ll be easy to split the supplies by just keeping my current supply for everything but the mount. In the field I’ll be using a single 12V 55Ah battery. I assume the mount power input is separate from the supply that will feed through up to the DEC axis and the supply that powers the USB hub. I guess if need be, some additional decoupling can be added around the dew controller if it ever caused issues for other 12V components. Maybe this is why I sometimes get mysterious image transmission failures.


On Sep 19, 2019, at 12:32 PM, chris1011@... <mailto:chris1011@...> [ap-gto] <ap-gto@... <mailto:ap-gto@...> > wrote:

Mount current draw is the following as measured at the power supply:

At 24 volts - 0.39 amps normal tracking. At 1800x - 2..06 amps 1 axis, 3.24 amps 2 axis slewing.

At 12 volts - 0.69 amps normal tracking. At 1200x - 2..91 amps 1 axis, 4.43 amps 2 axis slewing.

For 600x slewing, current draw is approximately half of the above

For 900x slewing current draw is approx 75% of above.

The mount comes with a 10 amp 24 volt supply (240 watts) and can be used with 120 and 240 volt input power.

If you run this mount from a different power supply, I recommend that you do not run dew heaters from that same supply since these put heavy spikes in the line that can disrupt the mount control circuit. Batteries tend to be ok since they can deliver the high inrush currents that dew heaters produce without dropping below the 10 - 11 volt min. limit that can cause motor stalls.

Roland Christen

Astro-Physics Inc.

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