Dynomotion

Group: DynoMotion Message: 6740 From: Concept4 Date: 2/15/2013
Subject: Open collector step/dir output.
Hi,

I have stepper motor drivers which have opto isolated inputs. I intend to configure the output channels as open collector.

It is a Leadshine M542 driver.

And here's a wiring diagram on how I'll be wiring these drivers:
http://www.mecheltron.com/files/images/stepper-motor-drivers/M542-schematic.png

What I'm trying to figure out is whether I need to use a pull up resistor on the KFlop outputs when connecting to the driver. Or can I just plug the output straight in to the negative side of the driver input.

Cheers
Group: DynoMotion Message: 6743 From: Tom Kerekes Date: 2/16/2013
Subject: Re: Open collector step/dir output.
Hi Concept4,

You didn't include a link to a specification for your drives.  I Googled and found this:

http://www.impulsecnc.nl/datasheets/leadshine/ManualM542V2.pdf

Technically they will not work with KFLOP because they specify they need 5us of Direction setup time before a Step Step pulse (see page 3).  KFLOP only provides 4us.  KFLOP was designed to work with high speed drives and it doesn't support this slow of a drive.

If there is not enough Direction setup time then there is a possibility of 1 uStep in the wrong direction for each reversal of motion.   Eventually such an effect can result in a significant loss in position.

The only proper solution I have is to add some sort of delay circuit (ie capacitor) to give 1us of delay to the step pulses.

Here is a link to a long cnczone Thread regarding the same or similar drives.  Where it apparently works ok with only 4us of setup.

http://www.cnczone.com/forums/dynomotion_kflop_kanalog/171759-help_having_trouble_moving_my_motors-3.html

You would normally connect the Step/Dir directly to KFLOP and operate KFLOP in open collector mode where it sinks current to ground.

HTH
Regards
TK