Axis motion with modulo and flying reference

[Plc_User]

In my appelication I have a chain to feed in a packet of plates into a machine. The conveyor chain moves only in one direction, and has pins on the chain to pickup the packet of plates and push it forward. At the end of the movement forward the packet is pushed more forward by other pushers, so the conveyor can rotate (always in the same direction) to bring its pins back to starting position, and so on.
The motor encoder (resolver) of the servomotor is used for position detection. There is a home sensor to reference the position after powerup.
This seems a typical application of an axis with modulus :
after a certain length the position goes back to zero and so on.
In my servo system (Sinamics S120) I can can setup a ratio of the motor rotatations to the rotations at the output of the gearbox, and I can also setup a length / rotation of gearbox.
My worry is that when my length / rotoation gearbox is not perfect, after multiple rotations my position will not be exat anymore. How do you setup position callibration if you have a continius forward rotating modulo axis? What is common practice?
How about doing a 'flying referencing' each rotation.
That would eliminate my error.
Thanks

 

[L D[AR2P#0.0]]

Does the home sensor activate each rev of the chain ?

 

[Plc_User]

Does the home sensor activate each rev of the chain ?

Yes, otherwise it could never be activated.
The movement of the chain is always forward.

 

[Plc_User]

No ideas?
I need urgent help.

 

[L D[AR2P#0.0]]

Check the encoder position each time the home sensor goes by, add the error as an offset to your actual posititon. Can you slow down the chain when the home is expected?

 

[Jeebs]

Not really my strong suit, as I've just had the training this monday and tuesday, but:
(note: this is the only way I know how to configure Siemens drives)

Sinamics S120 configuration > Drives > Whatever drive you have > Configuration > Configure DDS (you've prolly done this already) > First tab, select Basic positioner.
Selecting this adds the Mechanics tab. In this tab you can select the homing sensor to reset actual position to 0 again. Well you have to manually enter the homing sensor variable, not sure if you can search for it.

As I said, my experience in this is like 2 days worth, but think that's the direction you need to look into.