Re: Stepper Motor Controllers

["Pearson, Matthew R." <pearsonmr@ornl.gov>]

>> 
>> Regarding closed loop mode:  While I can imagine circumstances where you might
>> want to disable it, I would think that any controller that supports an encoder
>> would also provide a closed loop mode.  Is that not so?  I would think there
>> would be little advantage to supporting an encoder if it couldn't be used
>> directly by the controller during movements (i.e. isn't this question the SAME
>> as "Does it support a position encoder"?)
> I think so.
> Some controllers should be able to make "smooth movements" towards the
> target position.
>> 

Just to clarify this point. The Parker 6K series does support encoders, but not closed loop control on stepper axes. It's only for feedback to the user. For some stages where the mechanics are poor, or we lose steps, we have to use the motor record retry capability. It's best to have the controller do the closed loop, so it can move to position, or fail, without having software logic on top.

Cheers,
Matt