Help with calculating Backlash on Esprit 100ED & ZWO EAF

[oymd]

I’m struggling to set up the BACKLASH.

I am using NINA.

The focuser is new, the newer 5V one. I fixed it using the Takahashi bracket.

I had setup up another EAF on a WO Star 71, and it was much easier, and works perfectly. I do not recall how I had set it up, as I followed a YouTube video that I cannot find any more. There is VERY SHORT TRAVEL on the WO Star 71's focuser.

In NINA, I cannot find the option to set the focus to Zero or 30,000.

I am trying to rack the focus tube all the way in to the ZERO mark, and then tell NINA it’s at ZERO?

Alternatively, my focus point is around the 6 mark on the focus tube. I’d like to tell NINA that the mark SIX is at 30,000?

How can I do that?

Also, I keep getting multiple beeps when I am manually moving the focuser using ZWO’s hand controller for the EAF. Is it trying to tell me I am doing something wrong?

Here’s how I was trying to set up the backlash.

In NINA, I set the AF step to 20.

I moved the focuser using the COARSE button in one direction. That moves the focuser by 100 steps in one direction. (5x20)

 

I then used the fine button in the opposite direction and visually observed for any movement. Each click is 20/2, so 10 steps.

I was surprised to see that there was no movement until I pressed 19 times. That’s a backlash of 190?

That’s very high?

It’s brand new and the newer 5v one?

And it seems it works overall in one direction, but when I start testing in the opposite direction, it does not move at all?

[Stuart1971]

6 minutes ago, oymd said:

I’m struggling to set up the BACKLASH.

I am using NINA.

The focuser is new, the newer 5V one. I fixed it using the Takahashi bracket.

I had setup up another EAF on a WO Star 71, and it was much easier, and works perfectly. I do not recall how I had set it up, as I followed a YouTube video that I cannot find any more. There is VERY SHORT TRAVEL on the WO Star 71's focuser.

In NINA, I cannot find the option to set the focus to Zero or 30,000.

I am trying to rack the focus tube all the way in to the ZERO mark, and then tell NINA it’s at ZERO?

Alternatively, my focus point is around the 6 mark on the focus tube. I’d like to tell NINA that the mark SIX is at 30,000?

How can I do that?

Also, I keep getting multiple beeps when I am manually moving the focuser using ZWO’s hand controller for the EAF. Is it trying to tell me I am doing something wrong?

Here’s how I was trying to set up the backlash.

In NINA, I set the AF step to 20.

I moved the focuser using the COARSE button in one direction. That moves the focuser by 100 steps in one direction. (5x20)

 

I then used the fine button in the opposite direction and visually observed for any movement. Each click is 20/2, so 10 steps.

I was surprised to see that there was no movement until I pressed 19 times. That’s a backlash of 190?

That’s very high?

It’s brand new and the newer 5v one?

And it seems it works overall in one direction, but when I start testing in the opposite direction, it does not move at all?

In NINA open the setting on the EAF driver page, move the scope to the start, and enter zero and set in the driver..and then set a max steps of 30000 and then it won’t go above that amount…
The EAF focus motors are renowned for having quite a bit of backlash, so your figure is probably correct

[Richard_]

Funnily enough, the backlash with the EAF on my 120mm WO refractor was also approximately 190. I found that this was consistent in one direction (extending the draw tube out) but not always repeatable in the other direction. 

I use and ASI Air Pro and if I leave the backlash value empty, the software works it out for me. This is fine for me, so I didn't bother putting the backlash value in. 

[oymd]

3 hours ago, Stuart1971 said:

In NINA open the setting on the EAF driver page, move the scope to the start, and enter zero and set in the driver..and then set a max steps of 30000 and then it won’t go above that amount…
The EAF focus motors are renowned for having quite a bit of backlash, so your figure is probably correct

Many thanks for your reply. 
 

When you say, move the scope to the start, do you mean RACK THE FOCUSER ALL IN TO ZERO, or move the focuser to the point where I am roughly IN FOCUS? Which for me would be at the 6 mark?

Also, in NINA, you mentioned to set the figure to ZERO. Where can I do that?

I was on the Equipment ==> Focuser page, and there is no option to change the values myself?

Thanks . 

[Stuart1971]

5 minutes ago, oymd said:

Many thanks for your reply. 
 

When you say, move the scope to the start, do you mean RACK THE FOCUSER ALL IN TO ZERO, or move the focuser to the point where I am roughly IN FOCUS? Which for me would be at the 6 mark?

Also, in NINA, you mentioned to set the figure to ZERO. Where can I do that?

I was on the Equipment ==> Focuser page, and there is no option to change the values myself?

Thanks . 

When you have your focuser racked all the way in, you want NINA to report a position of zero, this way it won’t crash the focuser into the housing, as it’s its a rack and pinion, it can cause damage, and same for max settings, I always set my zero a few MM from the end…

Set it on the focuser tab, put zero in the box and sync…

[scotty38]

On the equipment page in NINA, before you connect, click on the gears icon and that's where you can set up the zero point. Within NINA i just kept nudging it in until there was a tiny gap before being fully racked in then, on the gears icon, set that as the Zero position.

[oymd]

4 hours ago, Stuart1971 said:

In NINA open the setting on the EAF driver page, move the scope to the start, and enter zero and set in the driver..and then set a max steps of 30000 and then it won’t go above that amount…
The EAF focus motors are renowned for having quite a bit of backlash, so your figure is probably correct

 

3 hours ago, Richard_ said:

Funnily enough, the backlash with the EAF on my 120mm WO refractor was also approximately 190. I found that this was consistent in one direction (extending the draw tube out) but not always repeatable in the other direction. 

I use and ASI Air Pro and if I leave the backlash value empty, the software works it out for me. This is fine for me, so I didn't bother putting the backlash value in. 

 

1 hour ago, Stuart1971 said:

When you have your focuser racked all the way in, you want NINA to report a position of zero, this way it won’t crash the focuser into the housing, as it’s its a rack and pinion, it can cause damage, and same for max settings, I always set my zero a few MM from the end…

Set it on the focuser tab, put zero in the box and sync…

 

1 hour ago, scotty38 said:

On the equipment page in NINA, before you connect, click on the gears icon and that's where you can set up the zero point. Within NINA i just kept nudging it in until there was a tiny gap before being fully racked in then, on the gears icon, set that as the Zero position.

Thanks, I founds the gears tab on the Focuser page.

So, using the ZWO hand controller, I racked the focuser all the way in till a few mm from the end, at the 0.5cm mark, and set to ZERO.

The focuser keeps beeping like crazy. While racking in the focuser, it just randomly goes at the SLOW option beeping every few seconds, then stops beeping when the focuser changes to FAST setting.

Anyways, I racked the focuser ALL the way OUT, and it reads as current position is: 17057?

How is that possible?

The focuser is at almost 9cm out.

If the focuser has 60000 steps, how come I am at 17000 from all the way in to all the way out?

[oymd]

5 hours ago, Stuart1971 said:

In NINA open the setting on the EAF driver page, move the scope to the start, and enter zero and set in the driver..and then set a max steps of 30000 and then it won’t go above that amount…
The EAF focus motors are renowned for having quite a bit of backlash, so your figure is probably correct

 

3 hours ago, Richard_ said:

Funnily enough, the backlash with the EAF on my 120mm WO refractor was also approximately 190. I found that this was consistent in one direction (extending the draw tube out) but not always repeatable in the other direction. 

I use and ASI Air Pro and if I leave the backlash value empty, the software works it out for me. This is fine for me, so I didn't bother putting the backlash value in. 

 

1 hour ago, Stuart1971 said:

When you have your focuser racked all the way in, you want NINA to report a position of zero, this way it won’t crash the focuser into the housing, as it’s its a rack and pinion, it can cause damage, and same for max settings, I always set my zero a few MM from the end…

Set it on the focuser tab, put zero in the box and sync…

 

1 hour ago, scotty38 said:

On the equipment page in NINA, before you connect, click on the gears icon and that's where you can set up the zero point. Within NINA i just kept nudging it in until there was a tiny gap before being fully racked in then, on the gears icon, set that as the Zero position.

Here is a screen shot of what's on my screen.

The focuser now is ALL OUT at 9cm.

 

Edited December 28, 2021 by oymd

[scotty38]

I'm not quite sure the effect it would have but have you set it to "reverse" in the screenshot?

[oymd]

1 minute ago, scotty38 said:

I'm not quite sure the effect it would have but have you set it to "reverse" in the screenshot?

It was set as that by default.

Tried unclicking it, and same thing, but in opposite direction.

From Zero position to the 9cm mark is 19000 steps.

And the beeping is driving me nuts!

I never ticked the beep option!!

[scotty38]

I'll check all my settings tomorrow and see what I have. Mine is a GT81 and I'm probably a third of the way out from zero at about 6/7000 steps so probably about the same as you for total steps....

[oymd]

7 hours ago, scotty38 said:

I'll check all my settings tomorrow and see what I have. Mine is a GT81 and I'm probably a third of the way out from zero at about 6/7000 steps so probably about the same as you for total steps....

I have the same exact EAF fitted to the WO Star71. 
 

It never makes a sound. 
 

I have no idea why this one I just fitted to the Esprit is non stop beeping?

I had a look in the manual, and there is no mention at all of the beeps? Not sure if it’s normal or an error code. 
 

The EAF is behaving very strange. 
 

during it’s travel, it changes from coarse to fine when I am racking in and out? When it’s moving SLOW it beeps with every step, then jumps to FAST and no beeps. 
 

And it moves to SLOW at the same places either way? At the 2cm mark, 4cm mark and 8cm mark. 
 

So, moving from 0.5cm to 9cm takes forever, as even if I choose FAST, it still moves at SLOW at those three levels and beeps with every step. 

[Richard_]

Before you installed the EAF, how did the manual focuser feel on the Esprit? Is it stiffer than your Star71? If there's more tension/resistance throughout the travel, especially at the 2cm, 4cm and 8cm mark, then that may explain why your EAF is beeping all the time. 

[scotty38]

4 hours ago, oymd said:

I have the same exact EAF fitted to the WO Star71. 
 

It never makes a sound. 
 

I have no idea why this one I just fitted to the Esprit is non stop beeping?

I had a look in the manual, and there is no mention at all of the beeps? Not sure if it’s normal or an error code. 
 

The EAF is behaving very strange. 
 

during it’s travel, it changes from coarse to fine when I am racking in and out? When it’s moving SLOW it beeps with every step, then jumps to FAST and no beeps. 
 

And it moves to SLOW at the same places either way? At the 2cm mark, 4cm mark and 8cm mark. 
 

So, moving from 0.5cm to 9cm takes forever, as even if I choose FAST, it still moves at SLOW at those three levels and beeps with every step. 

Hmmm have to agree that doesn't sound 100%, I'd be tempted to get it swapped out if you're able....

[oymd]

2 hours ago, Richard_ said:

Before you installed the EAF, how did the manual focuser feel on the Esprit? Is it stiffer than your Star71? If there's more tension/resistance throughout the travel, especially at the 2cm, 4cm and 8cm mark, then that may explain why your EAF is beeping all the time. 

Yes, it certainly felt stiff. I used the 4th coupler with the biggest hole, but it felt stiff. I have no other options to use. It’s the only coupler that fits. Should I sand it down a little?

[Stuart1971]

9 minutes ago, oymd said:

Yes, it certainly felt stiff. I used the 4th coupler with the biggest hole, but it felt stiff. I have no other options to use. It’s the only coupler that fits. Should I sand it down a little?

Sand it down…?? Sand what down ?

[oymd]

1 hour ago, Stuart1971 said:

Sand it down…?? Sand what down ?

The coupler feels rough on the outside. Where there are gaps for flexibility, the edges of the coupler are not well machined and there are tiny protruding edges. 

[oymd]

1 hour ago, Stuart1971 said:

Sand it down…?? Sand what down ?

I feel that the coupler is a tight fit inside the Esprit’s housing where the coarse knob was. 

[Stuart1971]

20 minutes ago, oymd said:

I feel that the coupler is a tight fit inside the Esprit’s housing where the coarse knob was. 

Ah, ok….yes well that may be where it is binding….

[scotty38]

I'm not sure I understand any of the above few posts. If by coupler you mean the 3 or 4 "flexible" adapters that come with the EAF then they shouldn't bind with anything. They attach the scope focus shaft to the EAF motor shaft but don't touch anything else so it shouldn't really matter how rough they are finished.

What am I misunderstanding here?

[Stuart1971]

1 hour ago, scotty38 said:

I'm not sure I understand any of the above few posts. If by coupler you mean the 3 or 4 "flexible" adapters that come with the EAF then they shouldn't bind with anything. They attach the scope focus shaft to the EAF motor shaft but don't touch anything else so it shouldn't really matter how rough they are finished.

What am I misunderstanding here?

The coupler fits into the scope focuser shaft, but it also slides slightly into the focuser housing, I think it’s here it’s binding, as the outside diameter is as wide as the focuser housing hole where the shaft protrudes….HTH…👍🏼

[scotty38]

oh ok thanks, on my WO the coupler does not slide in to any housing, guess it must be different on the Esprit.

[scotty38]

Couldn't help but have a search and I found this on CN... I see what you mean now....

 

[Stuart1971]

5 minutes ago, scotty38 said:

oh ok thanks, on my WO the coupler does not slide in to any housing, guess it must be different on the Esprit.

On my Tak FSQ85 it goes in about 2-3mm

[oymd]

30 minutes ago, scotty38 said:

Couldn't help but have a search and I found this on CN... I see what you mean now....

 

 

30 minutes ago, Stuart1971 said:

On my Tak FSQ85 it goes in about 2-3mm

Yes, exactly. The coupler on my esprit is a very tight fit in the focuser housing, same as the picture above.