Filter
Top Products
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.
2.3.1 16C550 UARTs
with 16-byte standard
Advantech UNO-2170 comes with TI16C550
UARTs containing 16
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)
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.
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.)
9 Chapter 2