Absolute Position MAH


Thread Starter

Offer dahan

Product: Rockwell Automation, kinetix 6000

We are using absolute encoder on the axis.
The thing is, and it is not a bug, it's a feature ļ

When using Absolute encoding if you are sending the command MAH (Motion Axis Home), while the drive is disabled, then the Zero point is being reset to the present position. Usually, to set a position we are using command MRP (Motion Redefine Position), but for some reason, only in absolute encoding, that is the case.

My question is WHY?? If there anyone out there who can explain to me why was it needed? Why we need another command to do the same thing? Why we have a command that can do 2 different things, while one of them is crucial for the operation.

I was asked by the customer, but could not give an answer!!

Thank you all.
When you use absolute MAH the current position is set to Zero. This position (when you use the correct feedback device) is "remembered" for when you power off.

Other Main differences:
- Can control the motion of the axis eg fwd/rev to find the home input
- Uses the Home input (slower response than the registration inputs)
- Can set the zero position remembered during a power off

- Can be used while the axis is moving to correct "on the fly"
- Is really a subset of the MAH command

Personally I use the MRP to redefine position
MAH I have not found to work the way I want. The Absolute position mode (zero remembered during power cycling) I find does not work on the equipment I program as there are mechanical changes that can occur while the power is off (worst case motor disconnected turned and replaced) that cause the Power On position to be incorrect.