Issue with '.PC' signal from MAH command on RSLogix5000 Ver20 & SERCOS Ultradrive

[Eoghan]

Morning.
Have a 2 Sercos Ultra 3000 drives configured onto RSL5k Version 20.
Drive are configured for active homing to switch and pulse.
Both drives are positioning correctly using MAM commands and giving me the '.pc' output from Function Block.

But I never get the '.pc' output after executing the MAH command. MAH command 'works'- in that it sends the axis to find the home switch and stop at this position once detected. I end up having to program a MAM command to position zero after the MAH command to ensure I know axis is physically at zero.

After MAH motion stops, the axis position display is non zero - varies between 0.5 and -0.5 mm. It is as if MAH command stops executing before it finds actual position.

Have tried upping Kp Gains and homing to switch but has not helped.

ANy suggestions as to what configuration might be inhibiting the MAH performance. Screenshots of motor config attached

 

[osmanmom]

I not familiar with this stuff,

Why the properties axis - Active without sequence (empty)?

 

[jmsmoreira]

Two questions:

Are you keeping the MAH instruction always active, or only on the rising edge?

Does the Axishomedstatus comes on when the servo stops (using the MAH instrucion?

 

[jmsmoreira]

I'm using it like this and it works fine:

 

[Eoghan]

Morning.
Have a 2 Sercos Ultra 3000 drives configured onto RSL5k Version 20.
Drive are configured for active homing to switch and pulse.
Both drives are positioning correctly using MAM commands and giving me the '.pc' output from Function Block.

But I never get the '.pc' output after executing the MAH command. MAH command 'works'- in that it sends the axis to find the home switch and stop at this position once detected. I end up having to program a MAM command to position zero after the MAH command to ensure I know axis is physically at zero.

After MAH motion stops, the axis position display is non zero - varies between 0.5 and -0.5 mm. It is as if MAH command stops executing before it finds actual position.

Have tried upping Kp Gains and homing to switch but has not helped.

ANy suggestions as to what configuration might be inhibiting the MAH performance. Screenshots of motor config attached

Issue resolved with the attached Rockwell Knowledgebase Entry 22214:
22214 - When executing a ControlLogix MAH instruction, (Motion Axis Home) the .PC bit (Process Complete) is never set


Access Level: TechConnect
Date Created: 06/28/2002 12:00 AM
Last Updated: 02/25/2013 09:16 PM

When executing a ControlLogix MAH instruction, (Motion Axis Home) the .PC bit (Process Complete) is never set.

Problem: On a Uni-directional home, the .IP bit is cleared, the AxisHomedStatus is set, but the .PC bit is not set.
Cause: If the home direction is uni-directional and the home offset is less then the distance required to decelerate, then axis is simply decelerated to a stop. The axis does not reverse direction to move to the home position. In this case, the .PC bit of the MAH instruction is not set. The .PC is set when the axis stops at the configured home position.
Verify:
Cure: To get the .PC to set, set the home offset to a value greater then the distance required for the axis to decelerate. To compensate for the home offset, set the home position to be the same as the home offset. For example. If the desired position at the marker is 0.0. When a uni-directional home is done, when the marker is seen the axis will move and decelerate to the position as defined by the home offset. This position is now defined as the Home Position. If the marker position should be 0.0, then make the home position equal to the home offset.