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Author Topic: AstroEQ out of sync?  (Read 351 times)

AradoKYSky

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AstroEQ out of sync?
« on: August 07, 2020, 12:26:44 »

Hello,

I seem to be running into an issue. My gear is based on RPI4B and AstroBerry 2.0.3. AstroBerry contains INDI and KSTARS. I have the AstroEQ using ttyACM. I use AstroEQLoader to setup AstroEQ. My mount is an old Celestron VIXEN Super Polaris.

Any clear night is the same. KSTARS and EQMOD arrive at the target. AstroEQ is halfway there. Instead of pointing south from north the device is pointing at the ground. I listen for slipping. My RA does chatter sometimes. It is more in line with the target than DEC. When KSTARS stops at the target, AstroEQ stops. AstroEQ hasnít finished getting there.

My AstroEQ config:
Motor Step: 1.8 degrees
Mount gear: 144
Gear Ratio: 3.0
Slew Rate: 94 <ó

This Slew Rate is my selection. Manually slewing to a target is smooth and faster at this setting. Any larger and slewing is a crawl. It isnít getting to the target. Something is out of sync. To me, it must be the slew rate. I have amps set to .7.

The motors are the same. I think the gear ratios might be overly optimistic. I used the stated specifications. The gears are not the same. The motors are the same style, NEMA17.

I will investigate the gear ratios. I will also check for symmetry within EQMOD.

How should the Slew Rate be set? To me, it should not cause any out of step issues. It is a speed control.
« Last Edit: September 07, 2020, 15:38:09 by AradoKYSky »
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AradoKYSky

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Re: AstroEQ out of sync?
« Reply #1 on: August 08, 2020, 19:01:40 »

Hello,

Hmm... the dec and ra pulley set screws were loose. That was the problem.
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TCWORLD

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Re: AstroEQ out of sync?
« Reply #2 on: August 09, 2020, 10:23:23 »

Glad you've sorted it.
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Tom Carpenter (AstroEQ)

AradoKYSky

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Re: AstroEQ out of sync?
« Reply #3 on: September 07, 2020, 05:50:11 »

Hello,

I resolved the loose pulleys. However, I think I have different problem. I have the same ratio 3:1 but 36:12 and 30:10 are different. The motors are the same. This looks like a design issue. Back to the drawing board.

Using this site for a ballpark answer, I found 36:12 is slower than 30:10 by 66.7%. This explains that issues that I am having. Less teeth and narrower belt means faster. I ordered a matching pair of 4:1 to produce an easier working relationship.

https://zalophusdokdo.github.io/StepperMotorsCalculator/en/index.html

« Last Edit: September 07, 2020, 15:45:50 by AradoKYSky »
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