Rockwell Automation 1758-RTU202 DataSite Hardware User Manual - Manual (Page 36)

Publication 1758-UM001D-EN-P - June 2011
36 Wiring the Controller
RS232 DB-9P Connector
When using RS232 serial connection, connect the interface COM of PC and
interface COM1 or COM2 of controller with data cables of 9-pin standard
connector (DB-9P).
In the following table an EFFECTIVE level means a voltage of +3V or
greater; a LEISURE level means a voltage of –3V or less.
Stop bits 1 or 2 bits
Communication protocol Modbus RTU, Modbus ASCII, DNP3
Protocol mode Master, Slave (DNP3 supports only slave mode.)
Connecting type DB-9P
Pin Assignments for RS232 Connector
Pin Function Type Description
Pin 1 DCD NC This pin is not connected.
Pin 2 RXD Input LEISURE for being in waiting state.
EFFECTIVE for receiving data, and the RXD LED will be
blinking.
Pin 3 TXD Output LEISURE for being in waiting state.
EFFECTIVE for transmitted data, and the TXD LED will be
blinking.
Pin 4 DTR NC This pin is not connected.
Pin 5 GROUND GND This pin is connected to the system ground.
Pin 6 — NC This pin is not connected.
Pin 7 RTS Output EFFECTIVE if full duplex operation is selected for the port.
EFFECTIVE just before and during transmission of data if
half duplex operation is selected.
LEISURE when no data is being transmitted.
RTS LED is lighting for an EFFECTIVE level.
Serial and protocol communication parameters (Continued)
Parameter Engineering value
5
GND
CTS RTS
TxD RxD
4 3 2
9 8 7 6
1
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