Go Down

### Topic: step sequence for unipolar motor (Read 1 time)previous topic - next topic

#### BetterSense

##### Feb 04, 2012, 07:11 amLast Edit: Feb 04, 2012, 07:15 am by BetterSense Reason: 1
Yes, this again.

I would be connecting the center tap (yellow and white) to my +12V and grounding the remaining wires with NPN transistors. I want to use a wave drive sequence:

0001
0010
0100
1000

I just don't know which wire is what!

I think this is equivalent:

BLK
BLU
GRN
RED

I thought I had it figured but it's not working. I'm trying to troubleshoot if it's my circuit or my step sequence.

#### MarkT

#1
##### Feb 04, 2012, 02:29 pm
Try black/red/green/blue and if that goes the wrong way reverse the sequence.  If A and B are the windings you want something like
A+, B+, A-, B- as the sequence.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

#### kf2qd

#2
##### Feb 07, 2012, 12:28 am
1000, 0100, 0010, 0001,... is not a wave sequence, but is called simple stepping.
1100, 0110, 0011, 1001,... is a wave stepping sequence

1000, 1100, 0100, 0110, 0010, 0011, 0001, 1001,... is half stepping and is a combination of the 2 previous sequences.

#### BetterSense

#3
##### Feb 07, 2012, 01:31 am
Ok. Thanks for the terminology clarification. But what I really need is to know which wire is what...

#### MarkT

#4
##### Feb 07, 2012, 05:40 pm
Well you can use a multimeter to determine if your motor is wired up as per the diagram.  Stepping is always A+/B+/A-/B- (or the reverse order)  Its arbitrary which end of a winding you call + or - BTW - if the motor turns the wrong way either reverse the sequence or swap +/- on one winding only.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

#### BetterSense

#5
##### Feb 08, 2012, 03:40 pm
Quote
Stepping is always A+/B+/A-/B-

Quote
Its arbitrary which end of a winding you call + or -

If it's arbitrary which end of a winding you call + or - then you are saying that any step sequence will work, as long as you alternate between coils, and switch polarity every time a coil is addressed. In other words, label the wires An and Am and Bn and Bm, then any sequence AnBnAmBm or AnBmAmBn or AmBmAnBn will work?

#### MarkT

#6
##### Feb 08, 2012, 03:53 pm
Yes, you just need to go round the circle in one direction of the other and not double-back or jump two steps in one go.

There are 24 permutations possible for 4 wires, but since its only the cyclic order that matters divide that by 4 to give 6 possibilities.  4 of those possibilities look like AABB and 2 look like ABAB, the latter two case are the ones you want.  You have 1/3 chance of getting a viable wiring at random in fact!

The problem is exactly that of visiting the 4 corners of a square once only.  Correct solutions don't cross a diagonal.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

#### Grumpy_Mike

#7
##### Feb 08, 2012, 04:03 pm
Quote
I just don't know which wire is what!

No I don't think anyone does. I have found I have to swap the wires round (or the sequence) until I get it right. After that the same colours from the same sort of motors are consistent.

#### BetterSense

#8
##### Feb 08, 2012, 09:23 pm
Thanks everyone.

Go Up

Please enter a valid email to subscribe