Yamatake DIGITRONIK SDC40A User Manual page 11

3-wire system
The DIGITRONIK instruments with the communication functions in compliance
with the RS-485 can also be used in the 3-wires system. An example of
connection methods in such a case is shown below.
Terminating
resistor
Master station
RDA
RDB
*
SDA
*
SDB
SG
FG
Shielded
cable
Shielded
cable
Terminating
resistor
Connect one terminating resistor of 150Ω 5%, 1/2W min. to the instrument at
each end of the transmission line.
Also connect the shield wires to FG at one place.
In the 3-wires system, the Yamatake Corporation CMC10L cannot be used as a
converter in the master station or slave station.
In an instrument equipped with only three RS-485 terminals, the asterisked (*)
wiring is done internally.
5-wire system
DIGITRONIK instrument
(slave station)
SDA
SDB
*
RDA
*
RDB
SG
FG
Shielded
cable
3-wire system
DIGITRONIK instrument
(slave station)
DA
DB
SG
FG
5-wire system
DIGITRONIK instrument
(slave station)
SDA
SDB
*
RDA
*
RDB
SG
FG
2. Wiring
2-3