Trinamic stepper: nearest/ farthest point problem

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wekrie

Trinamic stepper: nearest/ farthest point problem

Post by wekrie »

Hello,
I use the external stepper (Trinamic PANDrive PD3-110-42-232), a usb->rs232 converter cable (FTDI - USB-RS232-WE-1800-BT) with a Canon 5dMII and a Rodenstock lens.
General configuration and response of the ext. stepper seem to be ok together with helicon remote.
But I have definitively a problem to save the farthest and nearest point in helicon remote with the ext. stepper. Camera has the newest firmware with >>no<< problems saving farthest/nearest point in helicon remote in combination with a Canon Makro lens and its internal focus. In detail...
If I start saving i.e. the nearest point (hel. remote icon changes to show success) --> then moving step by step to the farthest point --> saving the farthest point -> start picture sequence from nearest to farthest ----> the stepper moves far "below" the nearest point, which was saved first --> the following microsteps & taking picture procedure are ok but are executed in a totally out-of-focus-range.
When beginning with the farthest point ..... picture sequence from farthest to nearest: same error.
Workaround: i.e. beginning with the nearest point & saving the nearest point --> then moving step by step to the farthest point --> saving the farthest point -> now differently starting picture sequence from farthest to nearest --> no complete and direct movement to first saved nearest point seems to be necessary -> focus range ok.
The whole thing seems to be an sw-error in helicon remote from my point of view.
Can you help? Is a fix possible?
I would like to work on with that very interesting ext. stepper procedure, making it i.e. battery driven, but would not spend any more time ( and money), if the basic mechanisms in helicon remote are not working properly.
Best wishes
Werner
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Stas Yatsenko
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Joined: 06.05.2009 14:05
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Re: Trinamic stepper: nearest/ farthest point problem

Post by Stas Yatsenko »

Hello Werner,

Thanks for the details. I would like to see photo of your setup to understand how it works and I would like to publish it on our site to demonstrate use of stepper motor to other users.

We checked with our motor and have not found any problems so far. I would recommend you to disconnect motor from the lens and put an arrow on the axis to see rotation exactly. Then save nearest point, make several big steps forward (>>>), safe farthers point. Then go back and forth several times and see if position is correct.

I suspect that lens has a slack, especially if movement of the motor is very sharp. So please make sure first that motor without lens produce the same effect.
wekrie

Re: Trinamic stepper: nearest/ farthest point problem

Post by wekrie »

Hello Stas,
you were right, I tried again and the steppermotor now moves correctly to the saved nearest and farthest point back and forth. Presumably the reason for the previous failure was, that the stepper was working or tried to work near or beyond one of the physical endpoints of the bellow (stepper can move it 4cm maximum). I see to send a photo when I finished the first real stacking tests.
Thank you for your help!
Best wishes
Werner
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Stas Yatsenko
Posts: 3841
Joined: 06.05.2009 14:05
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Re: Trinamic stepper: nearest/ farthest point problem

Post by Stas Yatsenko »

You are welcome. Keep us updated about your progress. It is always interesting to look at some non-standard solutions.
OLH

Re: Trinamic stepper: nearest/ farthest point problem

Post by OLH »

Stas Yatsenko wrote:You are welcome. Keep us updated about your progress. It is always interesting to look at some non-standard solutions.
Would really be interested to see that too!
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