How to measure the Zero pulse position relative to home switch position to determine if a motor needs mechanically rotating

Auteur Gareth Green | Dernière modification 20/03/2025 par Gareth Green en cours de rédaction ⧼frevu-button-review-label⧽

Difficulté

Difficile

Durée

10 minute(s)

How to measure the Zero pulse position relative to home switch position to determine if a motor needs mechanically rotating

Difficulté

Difficile

Durée

10 minute(s)

Sommaire

[masquer]

1 Introduction
2 Problem

Introduction

Problem

If the zero pulse position is very close to the the home switch position, a common fault can occur where the axis datum moves out of position by one rotation.

This manifests itself as a Y/Z axis being 5 / 10mm out or a gripper around 32mm out

The problem is easy to solve once detected, by either moving the home switch flag, or rotating the motor by one quarter turn.

However, this means the fault has to happen before detection.

This tutorial describes how to predict if this will be a problem, so the corrective action can be taken before it creates the issue

Étape 1 - Prepare

Enter setup mode and load the TwinCAT project

Étape 2 - Navigate to the axis

In TwinCAT, navigate to the Axis->Enc->Parameter->Homing

Reference Mode

Check which system the axis is using

PLC - This method uses just the home switch for zero. Fine for low accuracy axes (GY, GZ). The Zero pulse offset will not affect this mode, so STOP HERE.

Software Sync- This method uses the home switch then zero pulse seek. Better for higher accuracy, but opens the risk of this problem

Default - This is not a good setting because it is not clear which mode. It is a good idea to change this to Software Sync to ensure the best possible datuming method is maintained.

...If the axis uses PLC mode, there is NO NEED to continue this test