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MX 420 Installation and Service Manual
Speed Over Ground Pulse Output
The MX420 outputs the GPS calculated speed over ground in a pulse format. Refer to
the Specifications section of this manual for signal characteristics.
The pulse output is derived from either NMEA 1 or 2 ports (shared with the NMEA 0183
protocol) on the MX420. Therefore, these ports are available for either pulse output or
NMEA 0183 output. Don’t forget that only NMEA2 Out (Port2) can be either RS-232 or
RS-422 port. Pulse output NMEA1 is connected to the cable ( A) connector pins 6
(signal) and 7 (return; not ground). Pulse output Port 2 is connected to the cable (A)
connector pins 14 (signal) and 15 (return; not ground). These are RS-422 level
signals, and may not be compatible with every installation.
To setup the MX420 software, select the
CFG1/Log Pulses
screen. This screen
controls the output port (Pulse) of the speed over ground log output from the MX420 at
a user determined pulse rate of 100 to 500 pulses per nautical mile (200 is the pre-
selected value). The default condition of the Speed-Over-Ground output is not active.
External Alarm Output
The MX420 is held open (floating) during normal operations. In an alarm condition, the
external alarm pin is switched to ground potential. When an alarm condition is cleared
or acknowledged, the Ext. alarm signal will return to open condition automatically
(refer to table below for relay conditions). However, it is possible to retain the external
alarm condition by setting the “Retain external alarm:” to ON. At this setting, the
external alarm signal can only be cleared by correcting the problem.
Ext. Alarm Relay Conditions
MX420 turned OFF
Energized
MX420 Turned ON
(No Alarm)
Not Energized
MX420 Turned On
(With Alarm)
Energized
12 VDC Input Power
Failure
Energized
Summary of Contents for MX420
Page 1: ...Installation Service Manual MX420 Navigation System ...
Page 5: ......
Page 8: ...1 MX 420 Installation and Service Manual List of Components SECTION 1 LIST OF COMPONENTS ...
Page 9: ...MX 420 Installation and Service Manual List of Components 2 ...
Page 15: ...MX 420 Installation and Service Manual List of Components 8 ...
Page 17: ...MX420 Installation and Service Manual Technical Specifications 10 ...
Page 24: ...17 MX420 Installation and Service Manual SECTION 3 MECHANICALAND INSTALLATION DRAWINGS ...
Page 25: ...18 MX420 Installation and Service Manual ...
Page 32: ...25 MX420 Installation and Service Manual SECTION 4 ELECTRICALINSTALLATION DRAWINGS ...
Page 33: ...26 MX420 Installation and Service Manual ...
Page 49: ...42 MX420 Installation and Service Manual ...
Page 57: ...50 MX 420 Installation and Service Manual SECTION 5 INSTALLATION NOTES ...