Homing

This chapter describes how to perform homing with an NC axis.

Homing is started from the PLC with the "MC_Home" function block. "MC_Home" is located in the TwinCAT library Tc2_MC2.
Further information can be found in the documentation Tc2_MC2.

For homing, a referencing cam is required that generates a digital switching signal at a defined position on the travel path. During homing, this defined position is determined and stored as the reference position for absolute positioning.

The configuration procedure depends on how you transmit the switching signal to the TwinCAT NC. The following options are available:

• Apply a 24 V switching signal to a digital input of EJ7411.
• Transmit any signal from the PLC.
  For this option, the referencing cam does not have to be physically present. It can also be simulated via a digital signal.

In addition to one of these options, you can use the zero pulse on the C track of the encoder for referencing.