Wiring Eia-485 (Rs-485) Communications - Emerson FloBoss 107 Instruction Manual

FloBoss 107 Instruction Manual
5.4

Wiring EIA-485 (RS-485) Communications

5-6
Configure communications for the other built-in and modular
5.
communications, I/O modules, AGA meter parameters, and other
configuration parameters.
The EIA-485 communications provides for RS-485 signals on:
COM1 port located on the CPU (labeled 485).
COM2 located on the CPU when a communications module is
installed in slot 2.
COM3 located on the EIA-485 (RS-485) communications module
installed in slot 1.
Table 5-2 shows termination points for EIA-485 (RS-485)
communications.
The EIA-485 (RS-485) serial communication allows baud rates from
300 to 115.2 Kbps with standard differential data transmissions over
distances of up to 1220 meter (4000 feet). The EIA-485 (RS-485)
drivers are designed for multi-point applications with multiple devices
on a single bus.
EIA-485 (RS-485) supports the log-on security feature of the FB107 if
you enable security on the communication port using ROCLINK 800.
LEDs display the A (transmit/receive+) and B (transmit/receive −)
signals for EIA-485 (RS-485) communications.
Default values for the EIA-485 (RS-485) communications module are:
19,200 baud rate, 8 data bits, 1 stop bit, no parity, 10 millisecond key-on
delay, and 10 millisecond key-off delay. The maximum baud rate is
115.2 Kbps.
Wiring should be twisted-pair cable. The terminals and their functions
are Pin 1 is Terminal A and Pin 2 is Terminal B. Connect A on the
FB107 to A or "+", and connect B on the FB107 to B or "−". Should
you encounter difficulties establishing a connection, try reversing the
connections.
EIA-485 (RS-485) standards suggest placing a terminating
Note:
resistor at the end of the line. The value of each termination
resister should equal the cable impedance (typically 120Ω for
twisted pair).
Communications Issued Feb-07