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Single Axis Motion for axes configured as a gantry pair

Single Axis Motion for axes configured as a gantry pair

Established Member

We are using motion app 1.10.1.

I have 2 axes configured as gantry axis.  I am unable to call moveVelocity or MoveAbsolute on either axis unless gantry mode is activated.


Application requirements:

1) Need to be able to individually jog and position the axes before turning on gantry mode.  This is need for initial alignment.

2) Need to be able to break out of gantry mode for slave during movement and switch to indiviual MotionAboluste command to realign the axis in final positioning.




Community Moderator
Community Moderator

Hi Craig,

a MoveVelocity is not yet build in, a MoveAbsolute can be done in the following ways?

1. For an individual movement an axis you have to explicitly allow it and disable the gantry monitoring function for the time.

This can be done via the Datalayer:


It is recomended to reset the bit to false after the singe axis movement for safty reasons.

2. The message in your picture is because you configured the axes to be able to be part of a gantry but you didn't couple the gantry yet.

This has to be done with "ML_AxsAddToGantry" and remove it with "ML_AxsRemoveFromGantry"

3. Break out of the gantry mode is not possible while moving, you have to be in standstill (see description of ML_AxsRemoveFromGantry)


A workaround for you could be not to use gantry mode but to copy the command values from one axis also to the other axis in your application. But you have to do all the errorhandling by your application as well.


For gantry alignment there is an uncompiled example function block in CXA_GANTRYALIGNMENT which can be used and also adapted to your needs. This takes also care about the "move-alowed" bit.

This is a large gantry on wheels in a track and final position is made based on sensor inputs on both sides.  It would be more flexible to go from Gantry mode to MoveAbsolute on Fly.

Where can this library be found?

Hi Craig,

thanks for the feedback, will give it to the development for future improvements.

The library can be found in the PLC Engineering from Version 1.12 on.

see also the documentation "Functions" --> "Gantry coupling"

Community Moderator
Community Moderator

Here is the link to the actual documentation for Gantry coupling.