This symbol indicates the presence of devices sensitive to Electro-
static Discharge (ESD) and indicates that care must be taken to
prevent damage with the equipment.
Electrical equipment marked with this symbol may not be disposed of
in European public disposal systems after 12 August of 2005. In
conformity with European local and national regulations (EU Directive
2002/96/EC), European electrical equipment users must now return
old or end-of-life equipment to the Producer for disposal at no charge
to the user.
Product overview
Modbus was developed as a PLC communication protocol.
Modbus uses a master/slave data exchange technique. The master
(typically a PLC) generates queries to individual slaves. The slaves, in
turn, reply back with a response to the master. A Modbus message
contains the information required to send a query or request, including
the slave address, function code, data and a checksum.
Installation
C A U T I O N
Personal injury hazard. Only qualified personnel should conduct the tasks
described in this section of the manual.
Install the module to the controller
D A N G E R
Electrocution Hazard. Always remove power from the instrument
before making any electrical connections.
D A N G E R
Electrocution Hazard. High voltage wiring for the controller is conducted behind
the high voltage barrier in the controller enclosure. The barrier must remain in
place except when installing modules, or when a qualified installation technician
is wiring for power, relays or analog and network cards.
4 English
N O T I C E
Potential Instrument Damage. Delicate internal electronic components
can be damaged by static electricity, resulting in degraded
performance or eventual failure.
The Modbus network card can be configured to support RS232 and
RS485 communications. Terminal block J1 provides the user connection
to the Modbus network card. For more wiring details, refer to
and to the following steps to install the Modbus network card.
Table 1 Modbus wiring with RS232 or RS485
Connector Connector
Signal
block pin
number
J1
9
GROUND
8
Rx
7
Tx
6
GROUND OUT Signal common
5
B (-) OUT
4
A (+) OUT
3
GROUND IN
2
B (-) IN
1
A (+) IN
Table 1
Description
Function
Signal common
RS232
Input into the
RS232
module
Output from the
RS232
module
RS485
(Multi-drop network)
Output from the
RS485
module (Multi-drop
network)
Output from the
RS485
module (Multi-drop
network)
Signal common
RS485
Input into the
RS485
module
Input into the
RS485
module