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Direction pulse
« on: January 12, 2012, 02:16:22 PM »
I need a little help....
I am wrestling with a problem with my direction pulse.
When I connected my BOB to my stepper drivers no matter how they are connected the motors will not turn under power.
After reading as much as I could find that was relative, I went back to my test setup and checked the outputs.
I have a lovely pulsed output from the step pin, but from what I read I should have a pulse from the direction pin which leads the pulses for the step signal by a time interval.
Well thats as I understood the theory anyway.

What I have got is a pulsed output on the step pin, however the direction pin merely changes from a high to a low state and vice versa on changing the direction of jogging.

Is this correct? If it is not correct how do I adjust the Mach3 settings to produce the required pulse?

If the pulse is not required then do I need to change the wirring to the BOB?

I am a total novice at this, and what does not help is the number of permutations that stepper motors can work with little regard to how to apply it.

Ie. CW/CCW mode step and direction mode, and that you have to wire this gear either pos or negative depending on your breakout board.

I have Totally covered all bases with the wiring, and tried every permutation, yet so far all I am able to achieve is a motor which is held once the power is applied, and so far as I understand or misunderstand am missing a specific pulse on the direction to make it run.

Am I barking up the wrong tree?

One final question for now, the enable input to the stepper drive, is this needed or is it optional? the reason I ask is because all I currently want to do is prove the motors actually work under Mach3, so I can complete the mechanical part of the conversion then faff about with this electronic stuff after the conversion is complete.
Regards
Simon

Offline ger21

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Re: Direction pulse
« Reply #1 on: January 12, 2012, 03:05:18 PM »
Quote
What I have got is a pulsed output on the step pin, however the direction pin merely changes from a high to a low state and vice versa on changing the direction of jogging.

Is this correct?

Yes, that is correct.

The direction pin is not keeping your motors from spinning. Even if it wasn't working, the motor should still turn, but in only one direction.
The fact that you're seeing the direction pin means that Mach3 is working correctly, and the problem is probably with your wiring.

What drives are you using? Some drives are enabled by default, some are not. It all depends on the drive, and how it's wired.
Gerry

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Re: Direction pulse
« Reply #2 on: January 13, 2012, 02:32:07 AM »
Many thanks for that.
I have connected the enable line to the VCC 5 volt line and ground and this produces a held motor and also with it not connected when the rotor is then free to turn.
So if the direction signal is not required to get the motor to turn under power I'll double check the pulse timings and output voltage.
BTW the stepper drivers are model DQ860MA, I have already contacted the supplier for details on the stepper drivers, so fingers crossed all should become clear soon.

Offline stirling

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Re: Direction pulse
« Reply #3 on: January 14, 2012, 06:11:52 AM »
Hey simon67 - is the attached pic your drive? If so connect 5Vdc to PUL+, DIR+ and ENBL+, then connect PUL- to your step pin and set Mach to active low. Connect DIR- to your dir pin - doesn't matter whether Mach's set to active high or low for this - you can swap it later if your motors sping the "wrong" way. Connect ENBL+ to ground for now.

Make sure you have SW4 ON - (though these have been known to be wrong way round on the screen print)

Set SW1,2,3 to your desired motor current and 5,6,7,8 to your required microsteps - I'd suggest 1600 pulse/rev.

You should be good to go.

Ian

EDIT 14/1/12: If your BOB has optocouplers you'd be best to bypass them if you can as these drivers have optocouplers already.
EDIT 1/6/12: The last line of para1 should of course read: Connect ENBL- to ground for now. Thanks to those who took the time to point this out.
« Last Edit: June 01, 2012, 05:17:21 AM by stirling »
Re: Direction pulse
« Reply #4 on: January 15, 2012, 02:02:07 AM »
Many thanks for that.
The drivers are now wired and working.

Simon

Offline stirling

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Re: Direction pulse
« Reply #5 on: January 15, 2012, 04:42:23 AM »
Ideal  :)

Ian
Re: Direction pulse
« Reply #6 on: May 31, 2012, 09:11:32 PM »
Hello Ian,

On the setup instruction you have first connected ENBL+ to 5V.

After you say: "Connect ENBL+ to ground for now.".

Should it be ENBL- to GND ?

I have the same driver and today could not make it work.

Thanks,

Max

Offline rcaffin

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Re: Direction pulse
« Reply #7 on: June 01, 2012, 02:37:09 AM »
On the setup instruction you have first connected ENBL+ to 5V.
After you say: "Connect ENBL+ to ground for now.".
Should it be ENBL- to GND ?
So Right!
(Otherwise you sort out the +5 PS!)

Cheers

Offline stirling

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Re: Direction pulse
« Reply #8 on: June 01, 2012, 03:24:54 AM »
So Right!
(Otherwise you sort out the +5 PS!)
LOL - so easy to make typos isn't it (actually you'd short out the PS) but thanks for pointing it out.

Ian

Offline rcaffin

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Re: Direction pulse
« Reply #9 on: June 01, 2012, 04:32:13 AM »
Quote
(Otherwise you sort out the +5 PS!)
LOL - so easy to make typos isn't it (actually you'd short out the PS) but thanks for pointing it out.
Yeah, you would short out the PS, but that would certainly sort it out as well :-)  :-)  :-)

Cheers