A simple contoller for my telescope motors?

Thread Starter

Greg_M

Joined Jul 30, 2022
8
I have a telescope project and what I need to do is control these 3 items.

All 3 of these are telescope control units. They don't require a lot of power. They are just for positioning and cooling.

The STEPPERONLINE stepper is just for focusing. It moves a 6" mirror back and forth through a reduction unit and only has to do this once or twice a night.

The Lin Engineering stepper is just for rotating a camera and is only used once or twice a night.

The Sunon 80mm cooling fans are only run as the sun goes down to cool the telescope to night time temperatures and then are shut off.

I have both 12vdc and 24vdc available for power.

I have a 3 axis stepper motor control board with a 24v PWM output for a spindle motor.
I have tried a couple of PWM "converters" for the 12vdc fans and neither has worked for the fans but the board works great to run the steppers.

Whatever the answer is I need to control it remotely via USB or RS232 and have some simple software just to move the motors and turn the fans on and off.

So that's my problem and I come here seeking help.

NEMA 17 bipolar 4-wire
STEPPERONLINE
Voltage 2.8 Volts
Rated current 1.68A & resistance 1.65ohms

NEMA 17 bipolar 4-wire
Lin Engineering
4-wire
4118S-15 0.50A

3ea (in parallel)
Sunon 80mm cooling fans
12vdc 1.7w ea
d current 1.68A & resistance 1.65ohms

If there is an off the shelf solution I'd gladly do that.
If I have posted this in the wrong place I apologize.
Thanks
Greg
 

MaxHeadRoom

Joined Jul 18, 2013
25,626
One way that has a built in 24hr real-time clock plus timers etc, is a SmartRelay, there are a few Manuf. out there some with the software free.
Do you need to supply step/direction pulses to the drives at a certain time and rate?
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
With both motors I need to be able to move them back and forth. It does not matter too much about how fast they get there. The STEPPERONLINE motor is a pretty slow process which involves moving and looking, moving and looking over an over until it's as good as possible. The cooling fans are just run until the telescope mirror has been cooled. All this stuff is pretty subjective. If I want to get real fancy I could put a temperature sensor on the back of the main mirror and have a thermometer to measure the ambient air temp and the fans could run until they are equal. But that could take a long time.
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
No it's all random.
It's done from about 80' away in a nice warm room.
I go up the ladder to the observatory and turn on power to all the components. Then I go down the ladder to the "warm room" and start adjusting things like focus. You would think I would be able to just turn the fans on and let them run all night, but even that little bit of vibration will shake the scope enough to make the pictures fuzzy.
Once I get things running and focused (etc) I can get the automated picture taking software going and take a nap. But until then it's all hands on and fussy.
 

MaxHeadRoom

Joined Jul 18, 2013
25,626
So it sounds like remote manual control .
One idea is out of the DIY CNC control scene but just use the manual input operation.
It is slightly over-kill, but the PC based software (Mach3) is free, and the output can be either parallel port or USB.
Step/Dir stepper control signals.
The break-out boards can be had cheap.
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
I've seen those boards with both parallel and USB. Do you have to use the parallel and USB or can you just use the USB?

If I could use the board I have and run the fans with the 24 PWM spindle output, I'd be done.
Supposedly the converters (I tried) would change the 24PWM to 10vdc, but they didn't work.
I've also been looking at little USB controlled on/off switches. With that I could connect 12vdc (or 24dc) to the fans.
The problem is they don't really have software to turn the USB switch on/off.
 

MaxHeadRoom

Joined Jul 18, 2013
25,626
The cheap ones work ok, they use the parallel port and hook up to USB for the 5v power.
Mach3 Stepper and relay output, on screen HMI for control from the PC.
e.g. Break-out on ebay 373637219773
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
25,626
I guess the problem is that I don't have parallel pulled the 80' up to the observatory
If you are using, or need to use a PC to do the control all you need is a parallel port on your PC to the Break out board, (BOB),
They are rare now, but you can often find the connector on the MB or there is a very cheap PC slot cards for it.
What I suggested gives you a bit of a free PC software and HMI, so all you would need is the BOB, ~ $4.00. and some multi core cable , enough for what you are controlling out to the observatory.
There are also some USB controllers that work with Mach3,
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
I just discovered something I consider strange, but I'm sure there 's an explanation....
Just for grins I hooked up a 24vdc cooling fan to the 24v pwm spindle output.
Nothing happened.
For some reason I bumped the Y axis stepper motor and the fan started running.
I could then turn off the fan using the spindle control switch.
I didn't want to always move the X or Y axis to get the fan running so I tried the Z axis which nothing is hooked to.
It worked.
I think I need to ask someone who knows about these controller boards and maybe there is a setting that would make it possible to turn the spindle motor on and off with out having to bump the Z axis.
Getting closer.
 

dendad

Joined Feb 20, 2016
4,176
It may be worth looking at a 3D printer control board. They have all you need and are quite cheap.
Lots of support forums too.
But it sounds like you have just that.
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
This the one I am using. It cost $37.21 and does a bunch of things and is beginning to look like it will do everything I need...maybe.
Runs on 24vdc and USB. Uses Candle software to run it.

Board.jpg
 

Thread Starter

Greg_M

Joined Jul 30, 2022
8
Turns out the controller was set to laser mode (some how) and so it would not let the spindle be on unless it was moving. It was setting $32=1 which I have now changed to $32=0
Next problem is getting the limit switches to work.
 
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