How can rotate stepper motor?

[Shyamal796]

I want to rotate stepper motor using jonson counter 4017 IC. I also using bipolar stepper motor. I connected pin 3 2 4 7 (sequence) of 4017ic with stepper motor. But my motor was not rotate.

I can't understand why motor is not rotate. Help me please

 

[(*steve*)]

You need to drive stepper motors correctly. I'm not sure that a 4017 will create the correct bit pattern. Also (and this is the big one) it can't supply enough current.

edit: ok, it will work with a unipolar stepper motor, but you need to increase the current (perhaps using mosfets)

 

[Shyamal796]

I get right sequence using 4017. Using LED i saw that the the sequence is ok. but when i connect stepper motor it don't rotate or move.

I found that the motor 1st coil is 1, 3 pin and 2nd coil is 2, 4. I maintain this sequence on 4017 pin as 3, 2, 4, 7.

 

[(*steve*)]

And how do you deal with the issue of drive current?

 

[Shyamal796]

I'm using L293D motor driver IC for driver current.

 

[(*steve*)]

OK, then show us the circuit diagram you've used. And provide a link to the datasheet for the driver.

Have you verified that there is voltage to one winding?

Have you verified that the powered winding changes each time the 4017 is clocked?

Have you verified the order that the windings is powered is correct?

 

[Shyamal796]

Why my stepper motor not rotate?

I'm using 1Hz clock pulse using 555 timer and 4017 counter is used to drive ic L293D. 4017 counter works correctly but motor driver ic L293D does not show any voltage (also 0.85 Volt) to drive stepper motor.

I used this configuration. I can't find where is the problem in my circuit diagram. Please help me......

 

[(*steve*)]

The first thing is that you're not showing protection diodes as per the datasheet (see page 2).

I would recommend that you remove the existing load and place a red LED and a resistor (1k is fine) from each of the outputs to ground. Then watch to see if the LEDs light up as they should (you could also place 1k resistor and LED on the appropriate 4017 outputs too (1K and a LED won't load down the output too much).

If that is fine, reconnect the stepper (with the protection diodes -- you need 8) and leave the LEDs connected.

You should still see the LEDs light up in turn.

My suspicion is that if the LEDs light up with the motor connected and move in a sequence, that you have the sequence wrong.

And unless your circuit diagram is wrong, yes, you have the sequence wrong.

Look here.

Swapping the connections to pins 7 and 10 of the driver should do the trick for you.

 

[KrisBlueNZ]

(*steve*), the data sheet says that the D-suffix version of the L293 has the protection diodes built in.
I think you have the sequence wrong. If your sequence numbers on the four control signals are right, you will have the following sequence of signals on the stepper motor windings:
1. Gap, then winding L1 energised, positive to left end
2. Gap, then winding L1 energised, negative to left end
3. Gap, then winding L2 energised, positive to left end
4. Gap, then winding L2 energised, negative to left end.
I'm not sure how your stepper motor is designed, but I think the correct sequence should be:
1. Gap, then winding L1 energised, positive to left end
2. Gap, then winding L2 energised, positive to left end
3. Gap, then winding L1 energised, negative to left end
4. Gap, then winding L2 energised, negative to left end.
As I say, I'm not sure about this. Perhaps you could divulge a bit more of your secret information and tell us the part number of the stepper motor, and perhaps a reference to its data sheet.

Edit: Aha, (*steve*) has already pointed you to the answer to the correct order of control signals, on the Ben's HobbyCorner site.

 

[(*steve*)]

(*steve*), the data sheet says that the D-suffix version of the L293 has the protection diodes built in.

So it does.

Then the good news is that fixing the sequence will probably do the trick.

I am still confused that the OP says that the voltage never exceeds about 0.85V though. It may be worth connecting some LEDs to confirm that things are operating correctly. Double-checking the Vcc and Vcc2 pin are correctly connected may also be a good idea.

 

[KrisBlueNZ]

Hmm, yes. I'd suggest connecting a 2-pin bicolour LED (with series resistor) acoss each stepper motor winding, and yes, check the voltages on the VCC and Enable pins.
He doesn't say whether the motor moves *at all*. If the sequence was wrong, you'd expect it would at least shudder a bit. A bit more disclosure from the OP would be appreciated!

 

[Shyamal796]

Why i use protection diode? I'm using L238D that you have shown in the page no 8.

 

[KrisBlueNZ]

Right, the D suffix device doesn't need the external diodes. Steve didn't notice this initially, but we know now. You don't need external diodes.

 

[Shyamal796]

My problem is solved.

See the image.

Thanks to all.

 

[Shyamal796]

Now i need to increase clock pulse 1Hz to 100Hz for rotating motor quickly. 1Hz is not sufficient, to rotate my stepper motor speedy for my work. I also want to use variable for that.
What can i do? Please help.

 

[(*steve*)]

You see that 555 with the 1k and 150k resistor?

Calculate the value of resistance the 150k resistor should be to get a frequency of 100Hz. Then place a potentiometer in series with that resistor so that the total resistance varies from this new value up to 150K (it may have to be approximate).

Then you've done it!

 

[Shyamal796]

I use 10k pot replacing 150K VR. It's working very good. Thanks Mr. Steve.

 

[Shyamal796]

Now i want to rotate my motor 180 degree angle. How can i do using 4017 counter and clock pulse. help me ........

 

[Shyamal796]

I see that for 48 pulse motor rotate 360 degree angle. So if i can give 24 pulse clock wise and another 24 pulse anti clock wise. Then motor will rotate anti clock wise & ant clock wise. In which configuration i use? Can i use two 4017 counter for this?

 

[(*steve*)]

I use 10k pot replacing 150K VR. It's working very good. Thanks Mr. Steve.

Ensure you have a resistor in series with this. If that resistor falls to 0 ohms, bad things can happen.

Now i want to rotate my motor 180 degree angle. How can i do using 4017 counter and clock pulse. help me ........

As mentioned previously, you need a method to allow only a certain number of pulses through.

It's not particularly easy using the circuit you have.

I see that for 48 pulse motor rotate 360 degree angle. So if i can give 24 pulse clock wise and another 24 pulse anti clock wise. Then motor will rotate anti clock wise & ant clock wise. In which configuration i use? Can i use two 4017 counter for this?

Firstly, your current circuit can only turn the motor in one direction.

However you can cheat. If, instead of delivering one pulse, you deliver three very rapid ones and then pause, the motor will not be able to respons and will behave as if you took one step "backward"

Again, not easy to do with a 555.

The best bet is to use a microcontroller. With this you can eliminate the 4017 and drive the driver chip directly. You can step forward, or backward as you desire.

You also may be able to find drivers which allow you to provide clock pulses and a "direction".