Connections To The Com3 (Rs-485/Rs-232) Serial Port On The Cpu/System Controller Board - Emerson ControlWave EFM 3808 Instruction Manual

2.3.6 Connections to the COM3 (RS-485/RS-232) Serial Port on the
CPU/System Controller Board
Table 2-8. COM3 RS-485 Connector (TB4) on CPU/System Controller Board
Connector Name
TB4 COM3
RS-485 COM3
Port Cables
Revised Mar-2011
ControlWave Express Instruction Manual (CI-ControlWave Express)
You use jumpers W12 through W16 to configure COM3 of the
ControlWave Express for either RS-232 or RS-485 operation. See
Section 2.3.2 for information on these jumpers.
# Pins and Type
5-pin terminal block
Table 2-9 shows connector pin assignments for COM3.
If you use COM3 for RS-232 operation, pins 1 and 4 do not
Note:
apply.
Table 2-9. COM3 Connector Pin Assignment
Pin Signal
1 RXD+
2 RXD–/RXD
3 TXD–/TXD
4 TXD+
5 Power Ground
When serving as an RS-485 port, COM3 supports local network
communications to multiple nodes up to 4000 feet away.
Since the RS-485 port is intended for network communications, refer to
Table 2-10 for the appropriate connections for wiring the master, first
slave, and nth slave.
Essentially, the master and the first slave transmit and receive data on
opposite lines; all slaves (from the first to the nth) are paralleled (daisy-
chained) across the same lines. Wire the master node to one end of the
RS-485 cable run using a 24-gauge paired conductor cable (such as a
Belden 9843).
: ControlWave Express supports only half-duplex RS-485
Note
networks.
Installation
Notes
This port can be configured as
either RS-232 or RS-485.
Description
Receive Data + input (Not applicable for
RS-232 usage)
Receive Data – Input
Transmit Data – Output
Transmit Data + Output (Not applicable for
RS-232 usage)
Ground
2-19