Instruction manual

3
3. n : 1 Connection (Multi-link 2) 3-13
Serial Communications
Terminating Resistance Setting
• The terminating resistance of the ZM-300 series should be set on the DIP switch.
• When the PLC and the master station are connected via RS-422/485, set the
terminating resistance at the PLC and the master station (CN1).
• When the ZM-300 series (master and slave stations) are connected via RS-485
(2-wire), set the terminating resistance at the ZM-300 series master station (MJ1/2) and
the terminating slave station (CN1).
Terminating Resistance Setting Example
1. When the PLC is connected to ZM-300 series master station via RS-232C:
(b) (c) (d) (e)
FG
+SD
−SD
+RD
−RD
SG
SG
SG
+
−
+
−
FG
+SD
−SD
+RD
−RD
SG
FG
+SD
−SD
+RD
−RD
SG
Signal
Name
To be installed by the user
Terminal block
ZM-300 slave station
CN1+ZM-1TC
ZM-300 slave station
CN1+ZM-1TC
ZM-300 slave station
CN1+ZM-1TC
ZM-300
master station
MJ1/2
Terminating
resistance
(OFF)
Terminating
resistance
(OFF)
Terminating
resistance
(OFF)
Terminating
resistance
(ON)
Signal
Name
Signal
Name
Signal
Name
ON
12345678
CF auto load
MJ2 (modular jack 2) terminating resistance
Not used
CN1 RD terminating resistance at pins 24 and 25
MJ1 (modular jack 1) terminating resistance
RS-232C
ON
12345678
ON
12345678
ON
12345678
ON
12345678
ON
12345678
PLC
CN1CN1CN1CN1 MJ1/2
RS-485 (2-wire)
ZM-300 master station
(= Local Port 1)
ZM-300 slave station
(= Local Port 2)
ZM-300 slave station
(= Local Port 3)
ZM-300 slave station
(= Local Port 4)
Terminal block
When MJ1 is
used:
When MJ2 is
used: