Kinetix 6500 - CIP Axis home to torque

Hi guys,

Has anyone used or tested the CIP Axis home to torque AddOn in the rockwell sample code library - 055818.
A machine vendor wishes to use this as a means of homing all the servos. The vendor also does not want to use any Pos or neg over travel switches and rely on soft limits only.
The vendor does not use Rockwell by default for motion applications.

It seems rockwell have stopped using Torque to home in the Homing attributes when using CIP over EIP. (Sercos had Home to torque as a selection)
Looking at the AddOn it seems to Jog until the position error meets a limit test (When position reaches deadstop), then stops, then homes absolute.

Ok so the home function should only be used when things are dismantled or during maint tasks, but I'm trying to establish a robust system for years to come.

All the servo motors will be coupled to linear actuators.
My concern is the potential of mech damage if soft limits are overidden, and homing in the incorrect position if anything else causes a position error.

Any experience on the above topic would greatly appreciated.

Yes, your fears are justified.

You will need to limit the drive torque such that it is high enough to reach the true end of travel, but small enough that it won't damage the linear actuator when it does crash into the end. And yes, it will false home when something is starting to bind up or something is blocking movement. You will also need to set a limit to the amount of position error you will allow for indiction of end of travel. Again, the more you allow, the more damage you can do, and the less you allow, the more likely you are to false home.

A hard overtravel is a good insurance policy. If nothing else, it would be good to have a means of verifying that homing was successful (either moving to sensor after homing or having operators manually jog it to a position for verification. If it does false home, the risk of catastrophe is very real.

I haven't used the add-on. I rolled my own homing sequence when I used 5500 servos (CIP over EIP).

This is not a good idea.
How can soft limits work if the current position is not known?
The hard over travel limits are a must.
Also, I don't recommend torque mode on linear actuators unless there is some sort of brake to stop the actuator should power fail. I have seen instances where a power fail or fault caused the controller output to go to 0 but that didn't provide braking torque to stop the motion.

Are you using absolute motors?

You could use a marker on machine's structure, then operator moves the axis up to this marker and "home passive" position using a IHM.

This work should be used when a motor or linear transmission is uncoupled.

I have a similar application. I'm using a kinetix 350 and an incremental servo. I'd like to use Rockwell's Home to Torque AOI, like the OP above. I also have prox's set up for Positive/Negative hardware overtravel limits. I'll try to attach an image below.

My question is: How can I home to torque if it requires passing my negative hardware overtravel limit? It seems I'd have to programmatically disable the hardware over travel limits during the servo homing sequence. I imagine this is a common approach to using soft limits with torque homing, but is it also with hard limits? What is the "right" way to implement homing to torque and hardware overtravel limits?