Problem with stepper motor: is my stepping sequence correct?

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seemanta

Joined: 10 Jun 2006
Posts: 71
Helped: 2

04 Nov 2008 15:31 stepper motor sequence

Hi,
I have a stepper motor which was lying idle until I decided to make some use of it. I just want to first test it by making it turn for a full 360 degrees.

It has 5 wires: one is common and 4 are coil inputs. I have hooked it up with my AT89S52 and a ULN 2803 as per the link:
http://www.freewebs.com/maheshwankhede/stepper.html

The stepping sequence I have applied is:



                 Coils:                4                3                2                1


Excication pattern:                    ON             OFF             OFF            OFF  (1000)


                                       OFF            ON              OFF            OFF (0100)


                                       OFF            OFF             ON             OFF (0010)


                                       OFF            OFF             OFF            ON  (0001)

However, in stead of the motor rotating a complete 360 degrees, it behaves in a different way.

For the first pattern(1000) it just moves a bit in anti-clockwise direction, then it moves a bit in clockwise direction for the second pattern(0100) and then for the last two patterns(0010 and 0001), it does not move at all. So, after a complete step sequence the motion produced in the motor is just an oscillatory motion : a bit of anti-clockwise followed by a bit of clockwise motion.

What could be wrong here? Is my step sequence incorrect ? Can you please advise?

regards,
Seemanta

matbob

Joined: 15 May 2008
Posts: 19
Helped: 2

04 Nov 2008 16:49 wiring sequence stepper

Hi seemanta,

I have worked with a few stepper motors and the difficult part is surely identifying the correct stepping sequence. In most cases I figured it out myself by trial and error method. Try to turn the motor by applying supply manually ie, without using a microcontroller.
Before that make sure all the coils are working. You can use a continuity tester or an ohmmeter.
Best wishes...

FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

04 Nov 2008 18:08 incorrect windings of stepper

This happens when exciting the windings in a wrong order. It should be very easy to find the order, where any step moves forward.

P.S.: In addition, you should verify with an ohmmeter, that you selected the right wire as common terminal.

Last edited by FvM on 04 Nov 2008 18:32; edited 1 time in total

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

04 Nov 2008 18:32 why does stepper motor does not turn clockwise

The stepping sequency is correct, although, as others have pointed out, you need to determine which coil actually gets powered in which sequence for the motor to rotate correctly.

What bothers me most is that it does not move at all during the last 2 steps. Did you check the wiring? Are you sure the coils are OK? I would just connect them manually to a power supply and check to see if there is movement at the shaft. The shaft should move one step to one side or the other whenever you apply power to a coil. If there is no movement, then something is wrong with that coil.

elrayes

Joined: 03 Jun 2008
Posts: 164
Helped: 8
Location: Egypt

07 Dec 2008 12:38 how to connect a sequence motor start

the sequence you have created is right but i suspect in some other issues:

-send me the stepper motor wiring, cause you may mistaken in connecting the stepper wires to the driver.
if you have these colors connect them according to this sequence:
1 - brown
2 - orange
3 - black
4 - yellow
-connect the common wire to VCC and the coils terminals to ground via transistors or the driver, thats a better connection in my opinion.

hope it works

karim