Wiring The Communications Cables - Omron K7DD User Manual

3 Installation and Wiring
3-6

Wiring the Communications Cables

When you use the communications function, wire communications cables.
The K7DD has two lines of communications ports:
RS-485 communications 1 terminals and
communications 2 terminals. Use the
communications 1 terminals in priority.
Connect the devices such as the PC on which the
K7DD Support Tool is installed and the host
system (PLC, etc.).
The communications protocol is Modbus RTU.
 Example of Connection to K7DD Support Tool
The communications cables are used to make initial settings of the K7DD with the K7DD Support Tool.
Use the number 3 and 4 (communications 1 terminals) of the Push-In Plus terminal block.
Connect the plus (+) cable to the
number 3 terminal and the minus
(-) cable to the number 4 terminal
on the K7DD.
Crossover wiring is available as
this is a Push-In Plus terminal
block.
The connection configuration of
Master:Slave is 1:1 or 1:N. For
the 1:N connection, you can
connect up to 32 Units including
the host system (master).
The total cable strength depends on the baud rate.
For a baud rate up to 115.2 kbps, the total should be 500 m max. For a baud rate of 230.4 kbps, it
should be 200 m max.
Install a terminating resistance of 120 Ω, 1/2 W at both ends of the transmission path.
Use shielded twisted-pair cables (AWG 24 to AWG 16).
 Initial Setting of Communications Converter
The setting should be in accordance with the
Modbus RTU communications setting of the
K7DD. Set the communications-related
parameters, following the instruction manual of
the communications converter.
In this procedure, set the communications
parameters shown at right:
3 - 14
Symbol
Communications converter
RS-485 Ether (Modbus-TCP)
Terminating resistance
120 Ω, 1/2 W
3 4 3
(+) (-) (+)
K7DD K7DD
Up to 31 Units
500 m max. (115.2 kbps)
200 m max. (230.4 kbps)
Power Line Data Generator User's Manual (N233)
(A)
(B)
Name
(A) (3), (4): RS-485
communications 1 terminals
(B) (5), (6): RS-485
communications 2 terminals
Computer
LAN cable
(+) (-)
Terminating resistance
4 120 Ω, 1/2 W
(-)
Setting parameter Setting
Baud Rate 115.2kbps
Data Length 8bit
Stop Bits 1bit
Parity Even