Emerson Process Management Bristol ControlWave ExpressPAC - Manual (Page 40)

ControlWave ExpressPAC Instruction Manual (CI-ControlWave EPAC)
2-26 Installation Revised Mar-2011
 Ensure that DCD is high to transmit (except when dialing a modem).
 Verify that each RS-232 transceiver has one active receiver while
disabled (in power down mode); connect the DCD signal to the
active receiver.
 Set CTS to high to transmit.
 If the port is set for full-duplex operation, RTS is always ON.
 Ensure that DTR is always high when port is active; DTR enables
RS-232 transceivers.
Note
: Control DTR using the PORTCONTROL function block and
the _Pn_AUTO_DTR system variable in your ControlWave
project. If you turn DTR off through these mechanisms, the
port remains off, even though hardware is fully configured.
 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 surge protectors.
2.3.7 Connections to the COM3 (RS-485/RS-232) Serial Port on the
CPU/System Controller Board
You use jumpers W12 through W16 to configure COM3 of the
ControlWave ExpressPAC for either RS-232 or RS-485 operation. See
Section 2.3.2 for information on these jumpers.
Table 2-9. COM3 RS-485 Connector (TB4) on CPU/System Controller Board
Connector Name # Pins and Type Notes
TB4 COM3 5-pin terminal block This port can be configured as
either RS-232 or RS-485.
RS-485 COM3
Port Cables
Table 2-10 shows connector pin assignments for COM3.
Note: If you use COM3 for RS-232 operation, pins 1 and 4 do not
apply.
Table 2-10. COM3 Connector Pin Assignment
Pin Signal Description
1 RXD+ Receive Data + input (Not applicable for
RS-232 usage)
2 RXD–/RXD Receive Data – Input
3 TXD–/TXD Transmit Data – Output
4 TXD+ Transmit Data + Output (Not applicable for
RS-232 usage)
5 Power Ground Ground