B&B Electronics UNO-2170 Manual De Usuario
2.3 RS-232/422/485 Interface (COM3~COM4)
The UNO-2170 offers two RS-232/422/485 serial communication
interface ports: COM3 and COM4. Please refer to Appendix A.4 for their
pin assignments. The default setting of COM3 and COM4 are RS-422/485.
interface ports: COM3 and COM4. Please refer to Appendix A.4 for their
pin assignments. The default setting of COM3 and COM4 are RS-422/485.
2.3.1 16C550 UARTs with 16-byte standard
Advantech UNO-2170 comes with TI16C550 UARTs containing 16
bytes FIFOs.
bytes FIFOs.
2.3.2 RS-422/485 detection
In RS-422/485 mode, UNO-2170 automatically detects signals to match
RS-422 or RS-485 networks. (No jumper change required)
RS-422 or RS-485 networks. (No jumper change required)
2.3.3 Automatic Data Flow Control Function for RS-485
In RS-485 mode, UNO-2170 automatically detects the direction of
incoming data and switches its transmission direction accordingly. So no
handshaking signal (e.g. RTS signal) is necessary. This lets you
conveniently build an RS-485 network with just two wires. More
importantly, application software previously written for half duplex
RS-232 environments can be maintained without modification.
incoming data and switches its transmission direction accordingly. So no
handshaking signal (e.g. RTS signal) is necessary. This lets you
conveniently build an RS-485 network with just two wires. More
importantly, application software previously written for half duplex
RS-232 environments can be maintained without modification.
2.3.4 Termination Resistor (JP6)
The onboard termination resistor (120 ohm) for COM3/COM4 can be
used for long distance transmission or device matching. (Default Open.)
used for long distance transmission or device matching. (Default Open.)
9 Chapter 2