how to control a stepper driver board with a stamp

dexter

Merry X'mas!

I need help in connecting my stamp to the K158 bipolar stepper motor driver. Initially, I thought it will be safe to directly connect the I/O pins to the DIRECTION and STEP terminals, but somehow the two I/O pins I used got damaged in practically no time! I'm running 2 12V stepper motors off my driver board and am wondering if the motors are drawing too much current or voltage from the DIRECTION and STEP terminals. The description that came with the driver board says the two terminals are opto-isolated by 4N25 ICs and operates between 0V and 5V, so I am not exactly sure what caused the fault. I wonder if I should put some transistors and resistors between the I/O pins and the terminals, can I get some advice on this please?

Post Edited (dexter) : 12/24/2008 1:41:24 PM GMT

$WMc%

dexter

Are You sure this is the rite schematic "Doc1.doc" for the stepper driver? This looks like 2 H-Bridge drives for a brush type DC motor.



______________$WMc%________________Merry Xmas

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The Truth is out there

kelvin james

With the opto you are basically driving a led. Without a resistor, the current will be much higher than the stamp pins can handle. A ballpark figure would be 330 ohm. If the board was a kit, make sure it was assembled properly.


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dexter

Yes, the schematics in Doc1.doc belongs to the stepper motor driver. It came with the board. [noparse]:)[/noparse]

So, is it sufficient to just drop in 330 ohm resistors between the I/O pins and the terminals, or are there other stuff I should add?
Really need some advices as u can see, i'm quite a novice here. Much appreciated.

kelvin james

Dexter

Scratch my previous reply.
I see that there are already 1K resistors on the inputs of the optos. Do you have the negative terminals of the opto inputs connected to ground? You need a common ground between the stamp board and controller also. The info on this pretty iffy, if you look closely at the picture, you can see how the wiring is done.



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$WMc%

dexter

After I looked at the .jpg Mr. James sent to the post I guess it is a stepper driver.? I do have some ideas though.

If Your burning out I/O pins I would double check R1 and R2.They should be "BROWN-BLACK-RED" with a "GOLD or SILVER" 4th color band.I would also read this value with an Ohm Meter.

If R9,R10,R15,or R16 was accidentally placed in R1 and R2 place this would overload the I/O pin on the Stamp, as R9,10,15,16 value is only 150 ohms.

If R1 and R2 turn out to be 1Kohm resisters, I would then look for some kind of tracking across the traces on the board or a bad solder joint.

________Maybe this will be of some help______$WMc%________Happy New Year__

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The Truth is out there