Filter wheel help, please

[Joel Shepherd]

I'm just in from an ultimately unproductive first night with an Atik EFW2 and am not sure how to proceed.

I have it set up with a 9 1.25" filter wheel. During a short indoor test a few nights ago, it seemed to be working as expected.

Tonight when I plugged it and connected Atik's FilterWheelRunner to it, it reported itself as having 7 holes. After much fooling around with cables, restarting the program, restarting the wheel and finally rebooting the laptop, I gave up, unscrewed the whole optical train and checked out the wheel. It turned, but stiffly. When I took the cover off and pulled back the little shaft that turns the filter wheel it spun more easily. After doing that a few times it seemed like it was turning better so I re-assembled the whole train and tried again.

This time it correctly reported itself as a 9-filter wheel, and it made encouraging noises when I tried to select a filter. After an hour of collecting data, though, I realized that the filters weren't properly positioned directly in front of the camera: they stopped about half a filter diameter short. Now I'm packed up and inside.

What gives? Is there an adjustment I can make to reduce the pressure between the drive shaft and filter wheel, or otherwise enable the wheel to turn easily? Anyone else run into this sort of problem before?

Thanks in advance for any helo! -- Joel.

[Zakalwe]

Is there not a calibration routine in the software?

[Astroboffin]

Hi,

that all sounds very strange indeed, I used an SX wheel and as it uses a Hall sensor to detect filter position, it is virtually impossible for it not to be aligned with the hole.

i am pretty sure Atik uses a similar method of filter positioning, so even if it was very stiff and the drive wheel was slipping it should not report that the filter is in position until it is, I think they use a Hall sensor also which detects a metal peg in the edge of the wheel carousel, and the sensor is magnetised, so when it picks up the metal peg it can very accurately position it.

so if it is stopping short and saying that the filter is in the correct position, then it sounds like the hall sensor is failing in some way, maybe a loose wire or the sensor itself has failed.

contact Atik on there customer support email, they are very good and will answer pretty quick, if it needs repair they will turn it around very quickly, or they do here in the UK anyway.

hope that is of some help.

AB

 

[Joel Shepherd]

It seems that it is supposed to self-calibrate when powered up. According to Atik's documentation, the wheel rotates once to count the number of holes and a second time to align itself to hole 1. At the beginning of the evening, it was clearly failing to do both.

I don't see small pegs but do see small holes through the wheel, aligned with the filters, plus one extra, so I assume it is using those to align itself. It is hard to understand how that couldn't work.

Anyway, I just sent an e-mail to Atik and will follow up with the dealer here if that goes nowhere. I'm kind of wishing I'd simply gone for a mechanical wheel instead but am hopeful I can get this working.

Thanks -- Joel.

[Davey-T]

Sorry to hear about your problems Joel, I have an Atik EFW2 wheel that has been no trouble apart from occasionally not being recognised by the computer.

Atik support is very good, they usually respond quickly to email enquiries.

Dave

[Joel Shepherd]

Well, in the comfort of our bright, warm home office, I figured out two potential problems. First, once the wheel is on, if you turn it at all by hand (e.g. shifting by trying to unscrew a filter) it will not self-correct: you need to power it off and on again and let it go through its calibration routine.

Where I suspect I may have messed up, though, was when I re-installed the wheel after putting in the filters. I didn't pull the motor (and drive shaft) back: I just eased the wheel into place. I suspect now that that might have put some sideways pressure on the shaft (so it was no longer perpendicular to the wheel) or some such. In any event, tonight after removing the wheel, pulling the motor back, dropping the wheel back in and letting the spring guide the motor/shaft back into position ... it seems to be working correctly. Now I just need to wait 48 hours or so for another clear night or two and see if it still works. Oh well, leaves a night for dealing with the growing cable madness.

 

[ultranova]

Glad you hopefully got it sorted, just on a side note

like Dave said, he occasionally has the problem of the filter

wheel not being recognised, I also on have a similar problem

for me its all down to what usb thing I turn on first

Now I have my routine set its ok

Paul