Hello,

it is not possible to use 1 encoder for 2 position loops in your case.

I guess the motors are stiff mechanically coupled.

First motor run in closed loop position control and the second motor does e.g torque coupling.

There is a Simotion FAQ:

https://support.industry.siemens.com/cs/ww/en/view/103603156

Hello,

in this case two encoders are a must, because using just one encoder you would not measure any deviation between master and slave.

Hello,

a configuration with position control and an overlaid load sharing control is not possible. This would "fight" against each other. But I would say you don't need a load sharing control. 

You just need to setup your gantry in position control (each drive controlled via external encoder) and the load sharing results automatically.

What you need to take care of is the so called exception handling. What I mean is, you have to program the reaction of your drives in case one drive goes to fault etc.