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val_ltd
Associate III
January 27, 2013
Question

Stepper motor stops when ABS_POS register overflows.

  • January 27, 2013
  • 4 replies
  • 697 views
Posted on January 27, 2013 at 23:05

Hello, I am trying to rotate my stepper motor 5000000 micro-steps (in 128 micro-steps mode) and its size is bigger than ABS_POS register size (it only has 22 bits in two's complement format).

When the register overflows, the motor stops, instead restart the register. What is the way to rotate more micro-steps than the register size, without stopping the motor?

On the other hand,  Run(DIR, SPD) command only accepts data of 20 bits size ...

Thanks,

#abs_pos-register
This topic has been closed for replies.

4 replies

Enrico Poli
ST Employee
February 4, 2013
Posted on February 04, 2013 at 15:43

Hello, the device is not able to manage a motion longer than the ABS_POS register size. If you send a Move or a GoTo command with an higher value the most significant bits will be truncated (e.g. a 5,000,000 motion is interpreted as a 805,696).

If you need to manage longer motion you have to do it through your microcontroller.

Run command argument is the target speed value, there is no relation with the motor position.

Regards

Enrico

val_ltd
val_ltdAuthor
Associate III
April 13, 2013
Posted on April 13, 2013 at 10:50

Thanks, At the end, I did it as you told me.

val_ltd
val_ltdAuthor
Associate III
April 13, 2013
Posted on April 13, 2013 at 11:10

I have moved my last questions to:

my.st.com/public/STe2ecommunities/motordriver_ics/Lists/Motor Driver ICs and Boards

val_ltd
val_ltdAuthor
Associate III
April 13, 2013
Posted on April 13, 2013 at 18:11

I have moved my last questions to:

my.st.com/public/STe2ecommunities/motordriver_ics/Lists/Motor Driver ICs and Boards.