AUX Serial Port
Both the COM and AUX (when present) serial ports use a D-sub DB-9F connector
defined to be compatible with a a simple M-F DB9 extension cable and
connection to a standard PC serial port. Since the latter is rare these days
a USB-to-Serial adapter with DB-9M connector can make the connection.
The RS-232 AUX port is located at the top of the JNIOR next to the POWER and
Sensor Port Expansion Bus connections. In addition to the 3-wire communication
connections this port also supports RTS/CTS hardware handshake. The default is
115,200 Baud using 8 Data bits, 1 stop bit and no parity. Both hardware and
software flow control are disabled by default. The hardware RTS/CTS lines
need no connection for port operation.
---------AUX---------
\ (5) (4) (3) (2) (1) / DB9F Connector Front View
\ (9) (8) (7) (6) /
-----------------
Pin Assignments
Pin 2 - Transmit Out (Tx) Active driver output from JNIOR
Pin 3 - Receive In (Rx) from remote system
Pin 5 - Ground reference (GND)
Pin 7 - Request to Send In (RTS) from remote system
Pin 8 - Clear to Send Out (CTS) Active signal output by JNIOR
other - No connection.
RS-422/RS-485
On the Model
410 the AUX port may be configured for RS-422 or RS-485
operation. The latter allowing applications to fully support 2 and 4 wire
full-duplex multi-drop communication networks at up to 250 kBaud.
Early Model 410 PCBs included internal jumpers providing an easy way to bridge
Receive and Transmit lines for 2-wire RS-485. A third jumper provided the
necessary 120 Ohm termination resistor. For proper balancing a termination
resistor should be located at both ends of an RS-485 communication line.
While the jumper location on the PCB is no longer populated it remains
available and may be optionally soldered for this purpose. The bridging and
termination resistor can also be externally applied.
---------AUX---------
\ (5) (4) (3) (2) (1) / DB9F Connector Front View
\ (9) (8) (7) (6) /
-----------------
Pin Assignments (RS-422 and RS-485 Modes)
Pin 2 - 485TX (-) Active driver output from JNIOR
Pin 3 - 485RX (-)
Pin 5 - Ground reference (GND)
Pin 7 - 485RX (+)
Pin 8 - 485TX (+) Active driver output from JNIOR
other - No connection.
Proper RS-485 bridging (bi-directional 2-wire communications):
* short Pin 2 (485TX-) with Pin 3 (485RX-)
* short Pin 8 (485TX+) with Pin 7 (485RX+)
* include 120 Ohm resistor between plus (+) and minus (-)
lines at transmitter and farthest end of the line.
The Java com.integpg.comm.AUXSerialPort class provides support for
configuring and controlling the AUX Serial Port. This includes the driver
control necessary to support full-duplex 2-wire networking.
NOTES
The GND is not equivalent to the (-) negative power input in all models
except the 412DMX (which requires DC power). This GND floats somewhere
between the (+) positive and (-) negative power connections.
The JNIOR serial ports are not isolated. Care should be taken not to create
unwanted ground loops.
SEE ALSO
HELP Topics:
MODELS,
COM_PORT,
IOLOG
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