Slow stepper with 1062 (28 rotation per minute)

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Slow stepper with 1062 (28 rotation per minute)

Postby mjskier » Sat Mar 10, 2012 11:06 am

I'm connecting an STP-58D2017 motor to a 1062. It works, but very slowly. 28 rotation per minutes even with acceleration set to the max (8859.375)

Could attaching the wires the wrong way explain that behavior? It goes forward and backward as expected.

I found a phase table for that motor that shows the following sequence:
They have a diagram that shows that 1 coil is AB and the other A'B'

step A B A' B'
1: 1 1 - -
2: - 1 1 -
3: - - 1 1
4: 1 - - 1

Trying to map this to the 1062 table I came up with the following wiring
(I took all the entries in the 1062 table that had 2 powered poles, and offset the starting point until I found a sequence where the next full step had one pole in common with the previous one)

motor 1062
A D
B B
A' C
B' A

As I said, it works, but slow. Any idea?
The motor data shows that A A' is one coil, and B B' the other.

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Re: Slow stepper with 1062 (28 rotation per minute)

Postby mjskier » Sat Mar 10, 2012 11:42 am

One thing I was forgetting to set was max velocity.
But even setting it to the max (383.25) I only get about 56 rotation per minutes.

Shouldn't I get about 48 full revolution per second at max velocity?
My reasoning which you are welcome to make fun at:

383 half step per second
191 full step per second
4 step to a full revolution, so about 48 full rev per second

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burley
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Re: Slow stepper with 1062 (28 rotation per minute)

Postby burley » Mon Mar 12, 2012 7:12 am

From what I can see that motor has a 1.8 degree step angle. That means that 191 full steps per second is 343.8 degrees per second or approximately 57.3RPM. At 1.8 degrees per step there are not 4 steps per full revolution, more like 200.
Brian Burley
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mjskier
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Re: Slow stepper with 1062 (28 rotation per minute)

Postby mjskier » Mon Mar 12, 2012 9:21 am

burley wrote:At 1.8 degrees per step there are not 4 steps per full revolution, more like 200.


Oops. Nothing like starting with the wrong assumption! :oops:
So about 1 revolution per second is the max I can expect from 1.8 degree step angle motors then.

Just by curiosity, why the order of magnitude difference in max velocity between the 1062 (about 191 step / sec) and the 1063 (about 2048 step / sec)
Is it a limitation forced by the nature of the motor (unipolar vs. bipolar) or is it design choices on the boards?

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Patrick
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Re: Slow stepper with 1062 (28 rotation per minute)

Postby Patrick » Mon Mar 12, 2012 12:08 pm

It's a firmware limitation - the 1062 needs to manage 4 motors at once, whereas the 1063 only has to manage 1. Also, the 1063 switches into full stepping mode at the faster velocity, so you get more velocity per instruction.

-Patrick


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