Honeywell DCP301 User Manual page 50

Chapter 4. WIRING
3-wire system RS-485 mutual connection
Handling Precautions
Be sure to connect SG terminals each
others.
Failure to do so might cause unstable
communications.
Provide terminating resistor of 150
Grounding of the shielded FG terminal should be carried out at only one end and not both ends.
When there are only three RS-485 terminals, terminals marked * are wired internally.
4-18
Terminating resistor
Master station
RDA
RDB
*
SDA
*
SDB
SG
FG
Shielded cable
Shielded cable
Terminating resistor
5%, 1/2W min. at both ends of the communications path.
Slave station DCP301
SDA
57
SDB
58
RDA
59
RDB
60
SG
61
FG
Shielded cable
Slave station DCP301
SDA
57
SDB
58
RDA
59
RDB
60
SG
61
FG
Slave station DCP301
SDA
57
SDB
58
RDA
59
RDB
60
SG
61
FG