Serial Ports
The FX30E/FX60E has two serial ports (Figure 10). Each
port has a Universal Asynchronous Receive Transmit
(UART) capable of operating up to 115,200 baud. The
left port is an RS-232 port that requires a DB-9 male plug
connector. The right port is a non-isolated RS-485 port
that uses two wires with a shield connection and a
screw-terminal connector plug.
Note: A green receive LED and yellow transmit LED are
provided for each serial port. These LEDs are
located on the bottom board opposite of the serial
connectors (Figure 7). The LEDs are labeled on
the board (COM1, COM2) and are not visible with
the cover on.
RS-232 Port
An RS-232 serial port uses a DB-9 male connector and
always operates as COM1. You can use a standard DB-9
serial cable with this port. The FX30E/FX60E is a serial
Data Terminal Equipment (DTE) device, so connecting
another DTE device (computer) requires a null modem
cable. To connect the FX30E/FX60E to a Data
Communication Equipment (DCE) device (modem), use
a straight-through cable. Table 4 provides the standard
serial DB-9 pinouts.
Table 4: Serial Port Pinouts
Base RS-485 Port
(COM2) Pinouts
DB-9 Plug PinSignalPinout References
1Data carrier detectDCDDB-9 Plug (Male)
2Receive dataRXD
3Transmit dataTXD
4Data terminal readyDTR
5GroundGND
6Data set readyDSR
7Request to sendRTS
8Clear to sendCTS
9Not used on the FX30E/FX60E
RS-485 Port
An RS-485 non-isolated port uses a 3-position, screw
terminal connector and always operates as COM2. Use
shielded 18-22 AWG wire for this connector (refer to the
Telecommunications Industry Association/Electronic
Industries Alliance [TIA/EIA-485 standard]). As shown in
Table 4, the screw terminals (from left to right) are shield,
plus (+), and minus (–).
RS-485 Biasing
The FX30E/FX60E's RS-485 port has a pair of 2-pin
jumpers that can be shorted with jumper blocks to provide
biasing. When shipped from the factory, these pins are
not shorted and therefore, the RS-485 port is unbiased.
Biasing can improve RS-485 communications by
eliminating indeterminate idle states. When you install
two, 2-pin shorting blocks on the controller's RS-485 bias
jumper pins, the shorting blocks add two onboard 3.3K
ohm resistors into the controller's RS-485 circuit, as
follows:
• from RS-485 plus (+) to 5 V
• from RS-485 minus (-) to ground
Note: Only one device on an RS-485 trunk should be
biased. Otherwise, undue loading of the circuit
may result with fewer devices supported.
Note: RS-485 bias resistors are different than
termination resistors, externally installed at the
two physical ends of a daisy-chained RS-485
trunk, across the plus (+) and minus (-) terminals.
Termination resistors are typically 100 or 120 ohm
value resistors.
Note: If termination resistors are used, RS-485 biasing
is typically required.
16FX30E/FX60E Supervisory Controllers Installation Instructions
To Next Page
Loading...
