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Operation | HS80/MX575C/MX575D User Manual
Alarm signal
There are two wires (24 AWG multi-strands) on the output cable that are used for the external
alarm function. The color codes for the two wires are white and white/red stripe and are the
output of a relay. When this relay closes, the connection is complete on the user-defined
external notification device.
Watchdog
The watchdog is a timer that is controlled by the software that monitors if the heading is lost.
The watchdog software is compliant with IEC 60495.
Common commands and messages
¼ Note: When selecting your baud rate and message types use the following formula and
example to calculate the bits/sec for each message and then sum the results to determine
the baud rate for your required data throughput. Transmitting the commands listed
in “Commands” on page 27 and monitoring the messages in “NMEA 0183 and other
messages” on page 28 requires that the PC serial communication port be connected to the
RS-232 interface wires of the 18-Pin antenna cable of the MX575C/MX575D (see “PC to GPS
compass interface diagram” on page 54). The HS80/HS80A requires this optional cable.
Message output rate * Message length (bytes) * bits in byte = Bits/second
(1 character = 1 byte, 8 bits = 1 byte, use 10 bits/byte to account for overhead)
Example:
Message Rate Bytes Bits in byte Bits/sec
GPHDT 10 20 10 2000
GPROT 5 18 10 900
GPHDG 1 33 10 330
GPGGA 1 83 10 830
GPZDA 1 38 10 380
Total 4440
The next sections provides brief descriptions of common commands and messages for the
Smart GPS compass.
Commands
Command Description
$GPMSK Tune beacon to specific frequency
$JAGE Specify maximum DGPS (COAST) correction age (6 to 8100 seconds)
$JAPP Query or specify receiver application firmware
$JASC
Specify ASCII messages to output to specific ports (see ASCII
messages in Table 3-3)
$JBAUD Specify RS-232, RS-422 (output) communication rate
$JBIN Specify binary messages to output to specific ports (see Table 3-4)
$JDIFF Query or specify differential correction mode
$JGEO Query or specify SBAS for current location and SBAS satellites
$JI Query unit’s serial number and firmware versions
$JOFF Turn off all data messages
$JQUERY,GUIDE Query accuracy suitability for navigation
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