Despatch Protocol 3 Modbus Communications - Manual (Page 7)

Modbus Programming Manual A BOUT T HIS M ANUAL
Version 2 7
Copyright © 2012 by Despatch Industries.
All rights reserved. No part of the contents of this manual may be reproduced, copied or transmitted in any form or by any
means including graphic, electronic, or mechanical methods or photocopying, recording, or information storage and
retrieval systems without the written permission of Despatch Industries, unless for purchaser's personal use.
Character format: Always 8 bits per character.
Device Address: See below.
1.4.3. RS485 Device Addressing
The instrument must be assigned a unique device address in the range 1 to 255. This address is
used to recognize Modbus Queries intended for this instrument. With the exception of globally
addressed broadcast messages, the instrument ignores Modbus Queries that do not match the
address that has been assigned to it.
The instrument will accept broadcast messages (global queries) using device address 0 no matter
what device address is assigned. No response messages are returned for globally addressed
Queries.
1.4.4. Ethernet Configuration
For Modbus TCP communications (Modbus over Ethernet), the IP address can either be assigned
by a Dynamic Host Configuration Protocol (DHCP), BootP or AutoIP server on the network, or
manually assigned using the IP address allocation software tool.
The supported data rates 10/100BASE-T (10 or 100 Mbps) are automatically detected.