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Eiland Communications Limited Home PageThe use of Microcontrollers and Windows Programming allow the design of projects like the NMEA Filter as well as the writing of utility programs to assist fault diagnosis and equipment programming.We can supply specific products or recommend equipment to meet your needs.Find out who goes where! Detect monitor and be alerted by wanted and unwanted guests as well as protecting no-go areas.

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Programmable NMEA Filter/Processor PCB

With isolated I/O, RS422/RS232 compatibility, sentence filtering, NMEA processing and blocking options.

Function.The NMEA Processor accepts NMEA data, processes the data to a customer defined set of rules and then delivers the output in NMEA format.If you can define the function we can probably write a program to perform the operation and it won't cost a fortune!Note you will deal with the same person from start to finish on the project.

Some Real Examples

Land of Hope and Glory. A piece of surveying equipment could not be utilised to its full potential because it accepted only NMEA version 1.5 making it incompatible with a modern DGPS only offering NMEA version 2.3. The solution was a Filter/Processor with firmware to convert the NMEA sentence to the exact requirements of the survey equipment.

Wind of Change. A ship's anemometer had a NMEA output connected to the ship's fuel management computer but for some reason it worked intermittently. It was determined that at a wind speed of less than 10 knots the NMEA sentences had non conforming 'spaces' in them. The manufacturer had long since stopped supporting the anemometer so a filter was used with firmware designed to remove the spaces and re-transmit the data avoiding the need to replace an otherwise perfectly functional instrument.


RS422/232 NMEA Filter User Manual - Issue 10 .

RS232/422 NMEA Filter/Processor PCB


RS232 NMEA Filter

As a Programmable Filter.

All I really want is ...The NMEA Filter firmware provides a simple user programmable unit for 'grabbing' and passing a single specific NMEA sentence, effectively reducing information overload which can cause lock-up of older marine electronic equipment. Alternatively the Filter can be user programmed to block NMEA sentences or a series of NMEA sentences eg all sentences beginning $GP.

Filtering and Blocking is programmed using terminal software (e.g. Windows Hyperterminal) with ANY 5 letters of the desired sentence for example GPGLL+ or a proprietary sentence header. One output will then consist only of the desired sentence filtered from the input with checksum verification, the second output will be an unaltered real time re-transmission of the input.

In blocking mode the programming could be for example GPGLL-, blocking all GPGLL sentences. In this mode only one output signal is used, a re-transmission of the input but without the blocked sentences.

The programming information is retained in memory.

And it doesn't stop there!


Recognising that a lot of potential applications may be unique the software can be factory modified to a set of rules to provide manipulation of the NMEA format output to meet individual situations. We offer full support to meet your requirements. An 'on site' service is also available.

The concept of the processor together with the flexibility of Eiland Communications is somewhat universal. It can be designed to work at different baud rates, indeed it need not be NMEA or even a conventional baud rate.

For further information or if you are looking for something similar please contact:-Eiland Communciations Limited  

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