E+E Modbus Probes with

Beckhoff

- TwinCAT 2

DEVELOPER NOTE

Introduction

This document describes how E+E probes with Modbus RTU interface are connected to Beckho󰀨 hardware

and how they communicate by means of TwinCAT. Only the properties specic to Modbus communication are

described. Programmming knowledge in IEC 61131-3 under TwinCAT is required.

This description is addressed to trained personnel of the control and automation technology that is familiar

with the applicable national standards. For installation and commissioning of the components, the observance

of the documentation and the following notes and explanations is absolutely necessary. For each installation

and commissioning, the qualied personnel is obliged to use the documentation published at that time for each

installation and commissioning. The qualied personnel must ensure that the application or use of the described

products meets all safety requirements, including all applicable laws, regulations, provisions and standards.

Warranty and Liability

This application example is non-binding and does not claim to be complete with regard to conguration and

equipment as well as all eventualities. The application example does not represent customer-specic solutions, but

is only intended to provide assistance with typical tasks. You yourself are responsible for the proper operation of the

products described. This application example does not release you from the obligation to handle the product safely

during application, installation, operation and maintenance. By using this application example, you acknowledge

that we cannot be held liable for any damage beyond the liability regulations described. We reserve the right

to make changes to this application example at any time without notice. In case of discrepancies between the

suggestions in this application example and other E+E publications, such as catalogues, the content of the other

documentation takes precedence.

We assume no liability for the information contained in this document.

Trademarks

Beckho󰀨®, TwinCAT® and EtherCAT® are registered and licensed trademarks of Beckho󰀨 Automation Ltd.

Distribution and reproduction of this document, exploitation and communication of its contents are prohibited unless

expressly permitted.

Non-compliance obligate to compensation. All rights for the case of patent, utility model or design patent registrati-

on reserved.

Modbus RTU Interface

The Modbus RTU is used to read data from or write data to permanently dened data areas of a device. The in-

formation about which data are in which data area varies from device to device. To be able to address the Modbus

RTU, the Modbus settings must rst be dened (baud rate, parity and stop bits).

Communication is based on the master-slave principle. The communication always starts from the master by a

request. Each slave has an address which must be assigned once. If a slave recognizes that it has been addressed

by the master, it sends a reply. The slaves cannot communicate with each other. Nor can they start communication

with the master.

Hardware

In this demo application the following control components from the control manufacturer Beckho󰀨® were used:

• CX9020 Compact CPU (CX9020-0111/1GB)

• EL6021 RS422/RS485 interface terminal

• EL9010 EtherCat end terminal