5 OPTO-Isolated NMEA 0183 Data Inputs
Full galvanic Opto-isolated differential
inputs that fully comply with the NMEA 0183 standard specification. This
allows the input to work correctly with long cable runs, and/or in a noisy
This also allows the NDC-4 to offer up to 2500v of common mode voltage
difference (between its input and outputs). This will prevent any ground
loop damage occurring.
Inputs 0-3 have independently selectable baud rates of 4800 to 57600 baud;
Input 4 is fixed at 4800 baud.
(When the USB connection is in use, the number of NMEA opto inputs is
reduced to 4).
2 ISO-Drive Flexible Outputs
The ISO-Drive outputs are fully compatible
with the RS422 (NMEA 0183), RS485 and RS232 connections on the NMEA
listening device(s) the NDC-4 supplies data to, and offers total galvanic
isolation of up to 1500v between
the output and ground.
The full-differential output ensures better quality communications and
lower noise emissions on unshielded twisted pair cabling.
Outputs 0 & 1 have independently selectable baud rates of 4800 to 115200
NMEA and PC (USB/ISO-Drive) Outputs
Allows any NMEA device and PC to read the
combined NMEA data output. Furthermore, special NMEA codes are used to
label each NMEA sentence - allowing the NMEA device or PC to determine
where all the NMEA information originated from.
An ARM 32-bit microcontroller capable of 40
million instructions per second, and very large NMEA data buffers to allow
smoothing of short-term peaks in the NMEA data flow.
The hardware's firmware (software) can be
easily upgraded as and when necessary.
Combine Mode: Intelligent Software
Filters the valid data from all active inputs,
using the configured Inclusion lists, and then combines the remaining data
using a simple priority system. Highest priority input (1) has the best
chance of its data being added to the output combined NMEA data, and input
4 the lowest chance. This advanced user controlled system only operates as
and when it becomes necessary to reduce the NMEA data outputted (triggered
by very high loading of the combined NMEA output).
The ISO-Drive and / or USB output will always contain all of the NMEA data
(due to its higher Baud rate and bandwidth).
Autoswitch Mode: Intelligent Software
Determines the highest priority device with
valid data, based on one of three reasons - a failure to send any NMEA
data, an invalid NMEA sentence checksum, or if the validity flag(s)
contained within the NMEA sentence indicate that this data is not valid
and should only be used with caution (for GPS and Depth data).
The chosen input's data will be resent out the two ISO-Drive outputs (and
USB if available), allowing two different Baud rates to be used (typically
38400 Baud and 4800 Baud).
Very Low Current Consumption
Ideal for small vessels with small batteries.
Diagnostic Tri-Colour LED
Indicates current operation mode, volume of
data being multiplexed, or if a hardware fault has been detected.
IP66/IP68 Case and Gland Design
A very robust polycarbonate case with a high
waterproof certification. The small case size is ideal for space
High Quality Angled Screw Terminals
The 'moving cage' type terminals make cable
installation a simple and quick operation.