Honeywell DCP552 Mark II - Manual (Page 43)

4-15
● 3-wire system RS-485 connection diagram
Attach 1/2W or greater terminating resistances of 150Ω ±5% at each end of the
communications lines. Ground the shield FGs at one end in one location, not at
both ends.
When only three RS-485 terminals are provided, the areas designated with an
asterisk (*) are connected internally.
SDA
SDB
RDA
RDB
SG
SDA
Shield
SDB
RDA
RDB
SG
Shield
Shield
Master station
*
Terminating resistor
Terminating resistor
Slave station side DCP552
SDA
SDB
RDA
RDB
SG
RDA
RDB
SDA
SDB
SG
FG
Slave station side DCP552
Slave station side DCP552
*
60
61
62
63
64
FG
60
61
62
63
64
FG
60
61
62
63
64
FG
Chapter 4. WIRING