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4.0 SERIAL COMMUNICATION
The 32400 uses either full-duplex RS-232 or half-duplex RS-485
signals for serial communication. RS-232 is the most simple and
operates up to distances of 30m (100ft). The RS-485 option is
preferred in electrically noisy environments, in applications where
multiple units must be networked, or in NMEA marine applications
where RS-485 signals are required.
The full duplex RS-232 connection may transmit and receive serial
data at the same time.
The RS-485 connection is half-duplex meaning the unit cannot
transmit and receive at the same time. The 32400 internally manages
the switch between modes.
Many applications require the 32400 to transmit only. However,
RS-485 applications that require polling the 32400 or sending
commands to it require that the externally connected serial devices
must be capable of managing its own half-duplex switching from
transmit to receive.
At low baud rates with proper cable installation and connections,
transmission distances up to 7km (4mi) are possible using RS-485.
Baud rates of 1200, 4800, 9600, 19.2K, and 38.4K baud are
available. Most jumper-selected output formats force the baud rate
to a predetermined value. All serial signals use 1 start, 8 data, and
1 stop bit. Any externally connected serial device must be set to the
same baud rate as the 32400.
4.1 POLLING
When the serial output format is ASCII POLLED or PRECIP POLLED
(See the SERIAL FORMAT DIAGRAM), the 32400 sends data only
when it receives a serial polling command: "Mc!" where 'c' is the
unique address of the unit. The default address is 'A' but any alpha or
numeric character may be used (section 4.2 SERIAL COMMANDS).
4.2 SERIAL COMMANDS
Serial commands set operating parameters and report settings.
Jumper W1 must be configured for SOFTWARE mode for serial
command settings to be retained, otherwise default settings
based on jumper configuration will take effect at next power up.
Commands may be sent using a PC and simple communications
programs such as HyperTerm or any other properly configured
serial device. All commands that begin with CMD must end with
a carriage return (ASCII 13).
Commands may be sent at any time but it may be more convenient
to pause 32400 serial output. This is especially necessary with
half-duplex RS-485 communication.
Please refer to the table on the following page for commands
and definitions.
32400-90(R)
5.0 MAINTENANCE
The 32400 requires no maintenance in normal use.
Periodic inspection is recommended to verify correct operation.
6.0 WARRANTY
This product is warranted to be free of defects in materials and
construction for a period of 12 months from date of initial purchase.
Liability is limited to repair or replacement of defective item. A copy
of the warranty policy may be obtained from R. M. Young Company.
7.0 CE COMPLIANCE
This product complies with European CE requirements for the EMC
Directive. Please note that shielded cable must be used.
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