I just brought a L293D and has a M42SP-7 bipolar stepper motor which I take out from my old printer. This bipolar stepper motor has 4 wires ( 3 orange colour and 1 blue colour). May I know which lead wire is ( A, A bar, B and B bar) as mention in its data sheet? I know that the resistance of a same coil wire is very low. How do I know which one is A and A bar in the same coil? Can anyone tell me what is the control sequence of this bipolar stepper motor? The bioplar stepper motor data sheet I have attach it with this forum. Thank you first for your kind help.

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It's not that hard. just use continuity to determine the pairs that feed the same coils. if you don't have a dmm, just short 2 of the wires together. if the stepper is harder to turn, they go to the same coil.

Once you have the pairs, it doesn't matter which one is A or /A (A Bar). If they are switched, the stepper will go the opposite driection. It doesn't matter which pair you call A or B. If you have them reversed, the stepper will go opposite direction.

So, hook them all up, get it running and then decide if the direction is correct or not. If not, switch a pair or invert the direction sense in sw.

Just a thought, are you sure its a stepper? that's a rather odd color (er, colour) scheme.

Finally, measure the resistance of each pair. With the driving voltage, use ohms law to determine current and make sure that your L293D will handle it. You are probably fine - printer steppers don't pull a lot of current but it's a good idea to be sure.

 

Thanks, Philba for your kind reply. May I know what is the sequence in order to move the bipolar stepper motor because I am trying to use PIC16F877 to generate the step to move my stepper motor but I do not know the sequence. Can you please give me some idea? Thanks.

 

google for "jones stepping". It will tell you all you need to know. section 3 talks about basic control - important to understand. Then look at section 6 - Midlevel Control.

Phil