Manual modbus

Modicon Modbus Protocol Reference Guide
PI–MBUS–300 Rev. J

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Modicon Modbus Protocol Reference Guide
PI–MBUS–300 Rev. J

June 1996 MODICON, Inc., Industrial Automation Systems One High Street North Andover, Massachusetts 01845

DOK-

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Preface
This guide is written for the person who will use Modicon Modbus protocols and messages for communication in Modicon programmable controller applications. It describes how messages are constructed, and how transactions take place using Modbus protocol. This guide should be used in conjunction with Modicon user guides for the types of networks and programmable controllers present in the application. Familiarity with your network layout, and with your control application, is assumed. The data and illustrations in this book are not binding. We reserve the right to modify our products in line with our policy of continuous product improvement. Information in this document is subject to change without notice and should not be construed as a commitment by Modicon, Inc., Industrial Automation Systems. Modicon, Inc. assumes no responsibility for any errors that may appear in this document. If you have any suggestions for improvements, or have found any errors in this publication, please notify us. No part of this document may be reproduced in any form or by any means, electronic or mechanical, without the express written permission of Modicon, Inc., Industrial Automation Systems. All rights reserved. The following are trademarks of Modicon, Inc.: Modbus ModConnect Modcom 984 BM85 BP85 P190 RR85 SA85 SM85 SQ85

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