Stepper Motor Control

Hi everybody!
I would like to control a bipolar stepper motor using a uprocessor.
After reading some appnotes and designs i am a little bit confused about IO requirements.
So my questions are:
1. When do i have to use half bridge and when full bridge?
2. How many control lines do i need? (four for controlling current in two windings plus do i need any additional control lines?)

Thanks!

32 microstep value

All the answers step by step

Control of Stepping Motors
https://www.cs.uiowa.edu/~jones/step/

project bridge transistor for drive microstepping

Thanks but i alredy read that document and said that i am confused!
I would like to discuss this problem of mine in this topic!

half bridge, bipolar stepmotors

Tracid wrote :

1. When do i have to use half bridge and when full bridge?
2. How many control lines do i need? (four for controlling current in two windings plus do i need any additional control lines?)

Click to expand...

1. For stepper motor, you do not need half bridege or full bridge, what you need is a hi-power hi-gain transistor switch, such as ULN2003
2. Four line is enough

For more informatin, please take a look at Stepper Motor Controller
Connection Diagrams at :
**broken link removed**

stepper fast decay

I alredy succesfully complete a project to control an unipolar stepper motor.And there are used really ULNs or UDNs but i am talking about a bipolar type!

how many pwm do i need for stepper

H-bride for one winding motor - Bipolar drive

Half bridge for winding with a center tap motor - Unipolar drive

project pic microstepping

So as i understand i need 4 control lines for one winding and 4 for another winding so to drive a bipolar stepper motor i need together 8 control lines.

Added after 3 minutes:

or its possible to share the control lines?
Now i mean by two phase on control(because i need to microstep) and not the version where only one winding is on at a time.

Added after 2 hours 16 minutes:

I think i found example on what confused me.
Please look at the pictures in the attachments.
One uses XOR to prevent short circuit and only two control lines per winding are required and the other needs four control lines per winding.

So could anybody confirm me that its enough to use four lines for BIPOLAR stepper control?

related:cstep.luberth.com/pstep.html

H-Bridge is good methode for controlling motor.
DC or stepper motor.

I usually use Allegro motor driver IC in my design.
please take a look on below pictures.
You just need to drive source and sink transistor (name is for my prefer only)
It is up to you to use fast decay or slow decay mode. I usually use mix (fast +slow) decay. It will have less energy consumption.
I do not know exactly, what is your problem. Circuit or programming related.
please let me know

stepper motor circuit explanation

But for your circuit, it is enough to drive motor ....

Another things that you have to consider is maximum current to motor coil.
Please confirm to motor specification.

If you have a suitable microcontroller in your system, It is mean you have 4 inputs to motor driver for 1 bridge, for driving one bipolar stepper, you should have 8 inputs.
You could delete resistor and gates at input signal... you can save the money ....

Added after 20 minutes:

Please find this additional material.
sorry if you already have.

32 micro step motor driver ic

If i delete the gate i will need 8 pins but this way i will need only 4 and theres a big need for IO in my application.
Otherwise this was my problem-how many pins do i need.But i think is alredy solved.

One more question i have:
I did not find any document on the web that describes how to microstep an UNIPOLAR stepper motor so i decided
to find it out.
I wrote a little code which should rotate the stepper one direction in 1/16 microsteps.
I used software PWM at about 6,25kHz.
Unfortunately it doesnt work.The motor vibrates at high speed.

The most i think the logic i followed is faulty.

I show you on an example how did i built the logic(picture attached)
the motor needs four states(i think):
1b +
1a + --> 0V
------------
1b +
2a 0V --> +
------------
2a +
2b + --> 0V
------------
2a +
1b 0V --> +

Do you confirm this?

Or could you give me the correct sequence please?

step motor driver ic, 32 microstep

I do not know how you program.
please see the picture.
If you want to move to
Pos. 1.
Q1,Q3=ON, Q2.Q4=OFF
Pos. 2.
Q1,=ON, Q2,Q3,Q4=OFF
Pos. 3.
Q1,Q4=ON, Q2Q3=OFF
and so on..

it is depend on your program and microcontroller how to ON or OFF the Tr.
1 or 0 for the value.

In this example I use half stepping method, so just have 8 step per revolution.
Since you need 16 step a revolution. you can not use this driving method.
you may use microstepping method. micro stepping method is quiet different compare to full or half step driving.

Please let me know you circuit. I try to analyze from your circuit.

8pins of step motor

Excuse me but i must to write down what i think:

I saw many topics on several forums where people ask about microstepping.The problem with them is that
others are answering to it always with Full or Half stepping techniques.
And when people are asking for unipolar drive others answer with bipolar.
And when people ask about software solution others answer with HW solution from Allegro.
And whats the reason for it: what is in the question is hard to(or impossible) to find on the web and the answer what is almost the opposite is much easier because of the plentiful info on the web.


So returning to my problem:
Microstepping means contunuously varying the current in the two adjacent windings OR
varying the current in one winding while the second winding is at full power.
And for this PWM is used.
There are some application notes from Microchip which describe the microstepping of a bipolar motor.

But my question is what is the correct sequence for an unipolar type.

What i wrote in my first post is now i think wrong.
The new sequence i am thinking about has 8 different sequences.
1b +
1a 0-->+
-------------
1a +
1b +-->0
-------------
1a +
2b 0-->+
-------------
2b +
1a +-->0
-------------
2b +
2a 0-->+
-------------
2a +
2b +-->0
-------------
2a +
1b 0-->+
-------------
1b +
2a +-->0

+ means full power
+-->0 means bringing the current down
0-->+ means bringing the current up

You can forget about the driver circuit( bridges).
The sequence to energise the coils is what is important.
The illustration is a few posts upper!

PS: the microstep ratio depends on how many current levels do you create in the winding(for 1:16 ration there will be 16 differnet current levels)

Added after 4 hours 20 minutes:

8 sequence version verified!I tried it using a PIC16F84A and works!
Maybe theres a more torque version too(or just this one?).

I managed to do 1/32 microstep ratio.

So if help needed,just ask me!

microstep code

u will find that in Z80 microprocessor by Gaonkar

fast slow decay h-bridge

bipolar motor control

Strange schematic! any explanation or correction?

bipolar stepper motor controller programs

read this ;-)

Re: related:cstep.luberth.com/pstep.html

ayanim97 said:

H-Bridge is good methode for controlling motor.
DC or stepper motor.

I usually use Allegro motor driver IC in my design.
please take a look on below pictures.
You just need to drive source and sink transistor (name is for my prefer only)
It is up to you to use fast decay or slow decay mode. I usually use mix (fast +slow) decay. It will have less energy consumption.
I do not know exactly, what is your problem. Circuit or programming related.
please let me know

Click to expand...

Hello,I have one question for you, Have you been used L6205?How do you make the fast decay mode or slow decay mode on this chip?
Thanks a millions!