User guide

eWON 500-2001-4001-4002 User Guide - IO Servers Configuration
eWON 500®2001®4001®4002® Version 4_3_0 - User Guide - 10/5/05 - ©ACT'L sa - Page 77
6.3 Modbus IO server
6.3.1 Introduction
The MODBUS IO Server setup is the standard remote IO communication setup of the eWON. It is used to configure:
• eWON as a Modbus TCP slave
• eWON as a Modbus RTU master and as a Modbus TCP master.
The first feature (Modbus TCP slave) is specific to the MODBUS IO server; it is actually designed to provide access to eWON Tag values and,
unlike all the other IO servers, for interfacing field values with the eWON.
The second feature (MODBUS Master) is the actual IO server feature that provides an interface to the field values as a common IO server.
The eWON MODBUS IO server will give access to values in equipments having a MODBUS interface.
The interface can be:
• RS485 – MODBUS RTU protocol will be used
• ETHERNET/PPP – MODBUS TCP protocol will be used.
eWON can mix access to MODBUS RTU and MODBUS TCP, depending on the way the Tag address is defined.
6.3.2 Setup
6.3.2.1 Setup for eWON Server
Figure 45: Modbus setup for eWON server configuration
This page defines the eWON configuration when used as a Modbus TCP slave.
As described in the Tag configuration paragraph, each Tag can be published to Modbus TCP so that a Modbus TCP can read their values.
This setup screen defines the eWON address, and globally enables or disables the Modbus TCP slave feature.
eWON Server Properties Description
eWON server enabled
Globally enables or disables the Modbus TCP Server feature. If disabled, then any request
from a Modbus TCP master will be rejected, even if Tags are published.
Modbus TCP Unit address
This feature is used by some gateway but can usually be left to 1 because Modbus TCP
appears as a point to point connection.
Table 49: eWON server configuration - eWON as Modbus TCP slave