Gantry

Hello

I am trying to get my head wrapped around the Gantry component, I am also a total newbie at this. My machine is a gantry type plasma cutter with a stepper drive on each end of the Y axis. I think I need to use this component so I can home both sides to prevent racking. I found an example of using the Gantry component that appears to just use open loop stepgens. The HAL file I generated with PNCconf setup closed loop steppers using the PID component and connect two stepgens to one axis command. From reading the Gantry component manpage it appears to just work in position commands. Does this mean that I need to connect a PID component between the gantry.N.joint.NN.pos-cmd output pin and the stepgen input pin for each joint?

John

Ok, I may have at least part of the answer.

When PNCconf built the HAL file it connected two stepgens to one axis command. But both stepgens are not connected the same way. One stepgen is configured as a step_type 0, control_ type 1 ( velocity mode I think) and is connected to the axis position command VIA a PID component. The other stepgen is configured as a step_type 0, control_type 0 (position mode I think) and is directly connected to the axis command. So if I understand correctly then I need to do this:

Axis position command -> Gantry component
gantry.N.joint.00.pos-cmd -> PID component -> stepgen step_type 0, control_type 1
gantry.N.joint.01.pos-cmd-> stepgen step_type 0, control_type 1

I realize there are other connections require to make this really work.

John

You would need one additional control loop for the added joint, because you are adding an
additional independent stepgen

(and all stepgens will be configured the same with PID and stepgen in velocity mode)

Ok, I think I've got it. Attached are the present test versions of my .ini and .HAL files for your entertainment. I am sure there are errors in these but I cannot connect to my working hardware yet.

John