- Emerson Remote Terminal Unit Instruction Manual
CI-ControlWave Express Appendix C - Hardware Installation Guide / C-7
Step 1. Hardware Configuration (Continued)
Tables C-4A through C-4C provide the connector pin assignments for the Comm. Ports.
Note: The following facts regarding ControlWave Express RS-232 serial
communication ports should be observed when constructing communications
cables:
• DCD must be high to transmit (except when dialing a modem)
• Each RS-232 transceiver has one active receiver while in powerdown mode
(disabled); the DCD signal is connected to the active receiver.
• CTS must be high to transmit.
• When port is set for full-duplex operation - RTS is always ON.
• DTR is always high (when port is active); DTR enables RS-232 Transceivers.
• When port is set for half-duplex operation - CTS must go low after RTS goes low.
• All RS-232 Comm. ports support RTS, DTR, CTS, DCD and DSR control signals.
• All RS-232 Comm. port I/O signals are protected by LCDA12C surge protectors to
±4KV ESD.
Table C-4A - RS-232 Ports (COM1 & 2) Connector Pin Assignments
(COM1 Connector J4 & COM2 Connector TB3)
Pin
#
Signal
RS-232
Description:
RS-232 Signals
1 DCD Data Carrier Detect Input
2 RXD Receive Data Input
3 TXD Transmit Data Output
4 DTR Data Terminal Ready Output
5 GND Power Ground
6 DSR Data Set Ready Input
7 RTS Request To Send Output
8 CTS Clear To Send Input
9 - -
Table C-4B - RS-232 Port (COM1) Alternate Connector
(COM1 Connector J11)
Pin
#
Signal
RS-232
Description:
RS-232 Signals
1 GND Power Ground
2 RXD Receive Data Input
3 TXD Transmit Data Output
NOTE: Choice of COM1 connectors (J4 or J11) determined by jumper W18.
Table C-4C - RS-2 32/RS-485 Port (COM3) Connector Pin Assignments
(COM3 Connector TB4)
Pin
#
Signal
RS-232
Description:
RS-232 Signals
Signal
RS-485
Description
RS-485 Signal
1 - - RXD+ Receiver Data + Input
2 RXD Receive Data Input
RXD− Receiver Data − Input
3 TXD Transmit Data Output
TXD− Transmit Data − Output
4 - - TXD+ Transmit Data + Output
5 GND Power Ground GND Ground
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