Pub. 42004-550A
Elemec3
Console Manual
—Version 3.0
Page 54 of 114
P:\Standard IOMs - Current Release\42004 Instr. Manuals\42004-550A.docx
09/20
Modbus
Terminology
Modbus TCP uses the terms
client
and
server
to describe devices. A Modbus client establishes a
connection (virtual circuit) on a TCP network to a Modbus server. Through the established connection,
the client requests information from the server and the server replies to the client with the information
requested. A typical industrial control application consists of a network with multiple servers (i.e.
instruments or PLC inputs/outputs) and one (or more) clients (e.g. PLC CPU or SCADA system). Unique
IP addresses identify each client and server.
The E3 controller functions as both a client and a server. The E3 system internal Modbus device supports
up to 255 Modbus inputs and 255 Modbus outputs. The configuration screen displays the quantity of
available remaining I/O ports.
1.
Click the
M
ODBUS
button from the
S
YSTEM
P
ROPERTIES
screen to access the MODBUS
S
UMMARY
screen (see Figure 57).
The Modbus summary screen contains The built in E3
Modbus I/O controller, external Modbus TCP devices
added to the configuration, and command buttons to
add external TCP Modbus devices and edit inhibit groups.
2.
Select the
I
NHIBIT
G
ROUPS
button to selectively inhibit groups of inputs to the
Elemec3
system (see
the Inhibit Groups section).
3.
Double click an existing device
4.
Click the
A
DD
E
XTERNAL
D
EVICE
button to add external TCP Modbus devices (see the External
Modbus TCP Devices section).
Figure 57. MODBUS Summary
