[isvflorin]

Well, finally the Kflop is out of the bag, bought it 4 years ago and yesterday was powered up for the first time, funny how time flies and life priorities change. I'm having trouble either configuring my axes or the wiring.
The problem:
steppers turn in the Step Response screen, but in one direction only. Both CW and CCW motions manifest into only CCW motion.

The hardware:
Slo Syn MD7 stepper drives, 4 wire steppers (parallel). Kflop powered by dedicated PC PSU, MD7 powered by 54V PSU, all grounded together. MD7 has 5 inputs, Opto, Step, Dir, AWO, Reduce Current. Steppers wired with shielded cable outside of control box until connector on control box. Inside control box from stepper connector just twisted cable to MD7.

Wiring:
Stepper wiring identical (only 2 drives/axes). MD7 stepper drive has Opto and AWO pins wired to +5 from PC PSU, Step wired to JP7 Pin15, Dir to JP7 Pin16, second MD7 with corresponding Step to JP7 Pin17 and Dir JP7 Pin18. MD7 drives are currently set to 100 microstepping.

Channel setup:
Axis Ch0 set up as step dir to generator output Ch0, Axis Ch1 set up as step dir to generator output Ch1, nothing else. If I try to setup as Microstepping Axis, the motors won't turn at all. I tried adding 8 and 16 to the respective output channels and still same manifestation (different speed in Move), motors will only turn in one direction only. IO screen has output 8,9,10,11 and their states checkmarked.

I'm guessing the Dir pin is not getting the correct signal. A bit out of ideas for the moment. Any help appreciated.
Forgot to mention, PC is a WIN10 tablet with Creators Update installed before installing Kmotion and KmotionCNC.

[isvflorin]

I probed the Dir pins on both drives and on CW they are getting 0v , CCW going to 3.8V, my multimeter might be a bit off. So the Kflop is sending the right stuff on the Dir pins, I guess. Or is the 3.8V not high enough for the MD7 to pick up ?

[CNCMAN172]

isvflorin,
I think the issue you are dealing with is the SloSyn drivers was a CW and CCW input to change directions. The KFLOP is designed for STEP and DIRECTION which is Pulses on the STEP and either high or low on direction. Check the manual on the KFLOP can't remember if they had a way to configure it for CCW/CW control.

Russ

[isvflorin]

Russ, thanks for the input, Kflop has a way of outputting CW/CCW. But reading the Slo Syn manual looks like it really wants Pulse/Dir. I will try CW/CCW on the Kflop and see if it makes a difference. Also, judging by the Dir pin doing Hi/Low, it looks like it should work with normal Step/Dir output.

[isvflorin]

I just tried Open Collector and LVTTL CW/CCW output channels and motor still spins one direction only with the Move button. However, as opposed to normal Step/Dir channel, it starts spinning and doesn't stop to try and spin again in the opposite direction.
Using normal step/dir gen channel, with the Move button, the motor spins, stops, and spins again (supposedly in the opposite direction).
No joy.

[CNCMAN172]

I think you are missing the point. Look at the following drawing. The Driver wants CW/CCW unless that can be switched. The Kflop outputs Step/Direction. Notice on the CW/CCW how the pulses for movement go the the direction you are sending, when in Step/Direction the signal on the direction pins selects direction. Both the driver and Kflop must be in the same mode. I think you might be able to setup KFLOP for CW/CCW but I can't remember. I have the KFLOP and these type drivers but not using those drivers right now.

Russ


Attachment 364026

[TomKerekes]

Hi isvflorin,

I probed the Dir pins on both drives and on CW they are getting 0v , CCW going to 3.8V, my multimeter might be a bit off. So the Kflop is sending the right stuff on the Dir pins, I guess. Or is the 3.8V not high enough for the MD7 to pick up ?

It is sort of the reverse. Assuming the inputs are opto coupler LEDs (and series resistor) with the anode connected to +5V then when the KFLOP pin goes to 3.8V then the input "sees" 1.2V and should turn off. Usually the spec call for something like 0.5V to turn off. But since most LEDs require more than 1.4V to even begin to turn on it works ok. A simple test to see if this is a problem would be to disconnect the Dir pin and see if the motor runs the opposite direction.

Regards

[isvflorin]

Tom, thanks for stepping in. Makes sense. Unfortunately I'm away for a couple weeks and can't test now. Will report back after testing.
Russ, if you look above, I already tested CW/CCW output from Kflop after you mentioned it, still no joy, although motion was slightly different, but still one way only.

Tom - if the 3.8V is the culprit, what could fix it ? Pull up resistor ok ? LVTTL to TTL converter ?
Thanks for all your help.
Florin

[TomKerekes]

Hi Florin,

No rush from our end - but don't wait another 4 years

Tom - if the 3.8V is the culprit, what could fix it ? Pull up resistor ok ?

A pull up resistor probably wouldn't help. The KFLOP pin is diode clamped to the 3.3V supply. So it can't be pulled up much higher than 3.8V without high current and damage to KFLOP.

LVTTL to TTL converter ?

Possibly. But I believe the specs for LVTTL and TTL are actually the same. A high value is really only guaranteed in both cases to go higher than 2.4V. But a 5V TTL driver is less likely to clamp or sink any current below 5V.

A differential line driver (using one output only) such as this usually drives higher than 4V under light load.
https://cnc4pc.com/differential-line-driver.html

You might also try connecting the the Opto to 3.3V instead of 5V. In this case the Opto will definitely turn off, but then may only see about 3V to turn on. If the problem is 1.2V is turning it on then 3V should well turn it on.

HTH
Regards

[isvflorin]

Yes, definitely not another 4 years :-) Really looking forward to testing the setup with the new information.
Another question - any idea why there is no motion at all if I set up the Axis channels as "Microstepping" instead of step/dir ? The MD7's are microstepping drives, initially I assumed I was supposed to set the axis' up as "Microstepping" but I get no motion at all that way. Maybe the speeds were wrong...

[TomKerekes]

Hi Florin,

Microstepping is a term we use to describe our output mode where we directly apply sine/cosine currents to the motor coils using our SnapAmp. It doesn't apply to your case.

Whether the drives microstep the motors or not doesn't matter to KFLOP. From KFLOP's perspective they are just "steps" of some size. They could even be Servo drives that are told to move in steps.

Regards