EAF focuser settings

starvoyager

I’ve been using the EAF focuser with just a handcontroller ( no software ) for a number of months and now realise that it has a 60,000 step limit of travel one way and back the other way due to an audible warning beep and no movement.
I just bought second new EAF for my new telescope rig and decided to connect it via Ascom to my Capture software APT. When I open APT , select Focuser and then Settings , this launches the Ascom chooser. I then select EAF (1) and it displays all the current setting of the new EAF which has a current position of around 29,890 steps or roughly half way
My question is, if I manually focus the new scope on an object ( I mainly do DSO imaging ) with the EAF removed , then fit the new EAF focuser with its current position set at 29,890 steps ( or halfway ) then theoretically I shouldn’t run out of travel either way ( unless I change cameras or do some planetary imaging with Powermates etc.. ) I do use filters but they don’t change focus greatly.
Do I have the correct understanding on how these EAF focusers work in regards to travel either way ?
I welcome any comments and advice on the above
Thankyou

w7ay

starvoyager Do I have the correct understanding on how these EAF focusers work in regards to travel either way ?

What you describe will work just fine.

However, there is also another way that does not involve removing the EAF shaft from the focuser.

If you want to move past the maximum value (for example 65000), simply move the EAF to the max value, then reset the step value to the min value (usually 0). You can now drive the stepper motor towards the max value again, rinse and repeat until the focuser has reached the proper position.

If you want to move it in the other direction and want to go past minimum (e.g., 0), just move to 0, then reset the step value to the max (e.g., 65000) and then continue to move the EAF towards zero again. Rinse and repeat to get where you want to go.

It will be slow, since the ZWO EAF shaft does not rotate very fast, about one revolution per 15 seconds, perhaps. 5760 steps per revolution. Just set it to go to 65000, and go get a cup of coffee.

For other limitations of the EAF that ZWO does not document (linearity and backlash), see my earlier posting here

https://bbs.astronomy-imaging-camera.com/d/12562-5v-eaf-linearity-and-backlash

Chen

starvoyager

Thanks for the prompt reply
So what your saying is that the stepper motor has no mechanical limits either way and is driven and controlled by the Ascom software settings (or Capture software) in the Ascom “Max Step” box.
So recapping ( if I’ve read it correctly)
Ascom EAF
Enter 60,000 in the “Max Step” box
Move the focuser until you reach 60,000 as shown in “current position”
Then press “Set Zero” button
Enter say 65,000 or higher in the “Max Step” box
This should allow you to keep moving the focuser beyond 60,000 to what ever value is needed for focus
If going the wrong way , repeat the above and move the opposite way
Is that correct ?
I like being prescriptive when performing operations that way you don’t foul up (Sorry I’m a senior citizen )

Thanks

w7ay

starvoyager Enter 60,000 in the “Max Step” box
Move the focuser until you reach 60,000 as shown in “current position”
Then press “Set Zero” button

I don't use ASCOM, but INDIGO has a "Sync To Position" switch for focusers. When you select that switch, instead of moving an electronic focuser to some position, it simply sets the current "step position" to said position.

ZWO's programs like the ASICap has a SET button to do the same thing, and ASIAIR has a button with an "Edit" icon next to the "Current position" text field to do the same thing.

Sorry I’m a senior citizen

Sorry, that excuse does not work with me. I have been retired since 2005. Don't have many Perseid meteor showers left before I turn into star dust.

Just check the ASCOM manual.

Chen

starvoyager

Thanks Chen
Appreciate your help except the last comment which wasn’t needed on an Astronomy equipment forum
Being a senior citizen is not an excuse it’s a fact and sometimes people need help not judgement !!
I’ll leave it there