Motor drifting after start-up ASCOM driver.

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Aug 24, 2017, 7:41:45 AM8/24/17
to USB_Focus
The new USB_focus received is now connecting reliable using a active USB cable. I still have some problems and observations:

1) Every time after power restart and connecting the ASCOM driver the motor is moving to position 64000 and sometimes to 0! Very weird. Luckily my focus motor is connected to the fine know and can handle this range. How to solve this?

2) Temperature compensation seems to be active in the ASCOM driver (nice) but:
- 2a) Temperature compensation control seems to stop after a motor move.
- 2b) Coefficient is not adjustable in ASCOM driver.

3) If USB_focus is powered off while moving, the absolute position is lost. I assume the position is only stored after completing a move. This could result in a undesirable drift in position measurement and possible mechanical overload if the mechanical end position is reached.

4) Why are negative temperature coefficients not accepted and reverse is only possible with a checkmark? Some hints and indications in the software would be helpful.

5) No limitation in entering temperature coefficients above 999 but resulting in weird effects.

6) Software "Move-in" and "Move-out" buttons can’t be reversed.


Aug 24, 2017, 8:50:54 AM8/24/17
to USB_Focus,
Forgot to mention:

7) The reset button resets the absolute position without warning. For new users a warning would be helpfull since you have to correct this by uncoupling and coupling the motor.

Aug 24, 2017, 3:05:01 PM8/24/17
to USB_Focus,
Let me explain problem 1) in more detail:

As soon the PC is started and the ASCOM connection is established, the focuser runs wild to position 64000. If reverse is on (not revert) it run wild to position 0. The movement can be stopped by any move. After that there is not temperature control.
After a disconnect and connect ASCOM driver the focuser has temperature control. As soon any movement is made the temperature control is no longer working. Only connect and disconnect activates the control again. This behaviour is similar as the ASCOM simulator but not desirable. So to work with it, I have first 1) to stop the wild move. 2) Focus the telescope and then 3) disconnect & connect to start temperature control. Any fine tuning will stop temperature control. :(

For APT:
The focus controller is stable after first connect but also no temperature control. I assume APT writes to the focuser and stops the wild movement. APT has it’s own temperature control which works fine.

The focuser has already run twice against its mechanical limit so this problem is important to solve.


Sep 8, 2017, 7:00:25 AM9/8/17
to USB_Focus

With CCDciel no wild move,  so wild move problem seems related to MaximDL. Still I like to control the temperature using the ASCOM driver.  So is there internal temperature control using the ASCOM driver and how does it behave?

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