Emerson Process Management ControlWave XFC - Manual (Page 58)

2-16 / Installation & Operation CI-ControlWave XFC
COM1 - Port 1: RS-232 - (3-Pins on Terminal Block J2) - labeled LOCAL - Half Duplex
operation only
COM2 - Port 2: RS-232 - (7-Pins on Terminal Block J2) - labeled NETWORK - Full/Half
Duplex operation
COM3 - Port 3: RS-485 - (3-Pins on Terminal Block J2) - labeled RS-485 - Half Duplex
operation only
Communication Ports COM1, COM2 and COM3 support serial asynchronous operation as
listed above. Any communication port (COM1, COM2 or COM3) can be configured for local
communications, i.e., connected to a PC loaded with ControlWave Designer and OpenBSI
software.
Diagrams of RS-232/485 interfaces and connectors are shown in Figures 2-9 and 2-10.
Hardware connector pin wiring assignments are provided in Tables 2-2A through 2-2C.
2.3.2.3 RS-232 & RS-485 Interfaces
ControlWave XFC RS-232 & RS-485 communication schemes are discussed herein.
RS-232 Ports
An RS-232 interface supports Point to Point, half-duplex (Network and Local Ports) and
full-duplex (Network Port - COM2) communications (20 feet maximum, using data quality
cable). Half-duplex communications supported by the ControlWave XFC utilize MODBUS
or BSAP protocol, while full-duplex is supported by the Point to Point (PPP) protocol. The
ControlWave XFC RS-232 Network port may utilize a “null modem” cable (Figure 2-9A -
Top) to interconnect with other devices such as a PC, printer, another ControlWave series
unit when the ControlWave XFC is communicating using the full-duplex PPP protocol. A
half-duplex cable (Figures 2-9A - Bottom) may be utilized with the Network Port when the
ControlWave XFC is connected to another ControlWave series unit. If communicating
with a Bristol series 3305, 3310, 3330 or 3335 RTU/DPC, one of the cables shown in Figure
2-9B must be used. Refer to Figure 2-9C to connect the ControlWave XFCs Local serial
RS-232 Port (COM1) to a PC or a model 3808 Transmitter.
Note: The following facts regarding ControlWave XFC RS-232 serial communication port
(COM2) 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 power down 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.
• RS-232 Comm. Port 2 supports RTS, DTR, CTS, and DCD control signals.
• All RS-232 Comm. port I/O signals are protected by LCDA12C surge protectors
to ±4KV ESD.