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Presentation
The Modbus communication protocol is of the master/slave type.
Two exchange methods are possible:
Request/reply:
The request from the master is addressed to a specific slave.
The master waits for the reply to be returned by the slave polled.
Distribution:
The master distributes a request to all the slave stations on the bus.
These stations execute the instruction without sending a reply.
Zelio Logic modular smart relays are connected to the Modbus network via the
Modbus slave communication module. This module is a slave that is not electrically
isolated.
The Modbus slave communication module must be connected to an SR3 B
ppp
BD
modular smart relay, with a
c
24 V supply.
b
v
v
b
v
Configuration
The Modbus network slave communication module can be configured:
independently, using the buttons on the smart relay
(1)
.
on a PC, using “Zelio Soft 2” software, see page 9.
When using a PC, programming can be performed either in LADDER language or in
function block diagram (FBD) language, see pages 10 to 13.
b
b
Description
Modbus slave communication module
SR3 MBU01BD
comprises:
1
Two retractable fixing lugs
2
AModbus network connection (RJ45 screened female connector).
3
A communication LED (COM).
4
A “Power on” LED (PWR).
5
A screw terminal block for the protective earth connection.
6
A spring for clip-on mounting on a 35 mm mounting rail.
7
Two locating pegs.
8
Two locating pegs for clip-on fixing.
(1) Programming from the front panel and buttons on the smart relay is only possible in
LADDER language.
Modbus communication module
Characteristics :
page 36
Functions :
page 37
References :
page 42
Dimensions, mounting :
page 43
524131
Presentation,
description,
1
COM
SR3 MBU01BD
MB485-V1
PWR
6
1
8
8
2
5
3
4
1
7
7
Zelio Logic smart relays
1
Communication
Modbus slave communication protocol
1
2
3
4
5
6
7
8
9
10