# Delayed activation of zero pulse logic

## Activation

A path offset can be specified in the parameter “kenngr.shift_offset_zero_pulse_activation“ P-AXIS-00494 for CNC-controlled homing (see P-AXIS-00299) in order to delay activation of the zero pulse logic after the reference cam is operated.

This parameter is 0 in the default setting. The zero pulse logic is immediately enabled when the reference cam is operated.

## Operating principle

If the reference cam and zero pulse are located close together, the zero pulse may not be detected reliably since detection of the next or the next but one zero pulse depends on the activation speed of the reference cam. See figure below:

The zero pulse may not be reliably detected

In this case a shift of the activation point for the zero pulse logic ensures that the identical zero pulse is always detected:

Activation time shift of zero pulse logic ensures identical zero pulse

## Notice

After homing, the position offset between the activation of the reference cam and detection of the zero pulse can be read out via the CNC object “reference cam - zero pulse offset”:

- Geo task,
- index group: 0x20300/
- index offset: 0x10000 * (axis_index + 1) + 0x11C

Examples | 1. axis -> index offset 0x1011C
| 3rd axis -> index offset 0x3011C,