Programmable NMEA Filter

OEM PCB From £110 (€135)

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

Alternatively the unit can be supplied as an active splitter without filtering, one isolated input and two outputs.

Intended for marine/shipboard use only the NMEA Filter is a simple user programmable unit for 'grabbing' and passing a specific NMEA sentence, effectively reducing information overload which can cause lock-up of older marine electronic equipment.

Alternatively the Filter can be programmed to block NMEA sentences or a series of NMEA sentences eg all sentences beginning $GP.

The power requirement is 12V or 24V DC+30%,-10%. The NMEA input and outputs are isolated from each other and from the DC supply.

The same unit can be factory customised to correct or modify NMEA sentences from earlier generation equipment to provide an output recognised by more modern technology.

Programmable NMEA FIlter User Manual - Issue 8.

Filtering and Blocking

Using terminal software (e.g. WIndows Hyperterminal) the unit is programmed 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-. 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.

Flexibility

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.

Some Real Examples

An expensive piece of surveying equipment could not be fully utilised 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 was used with firmware to convert the NMEA sentence to the exact requirements of the survey equipment.

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.

As a Tool

As a service tool it can be used to filter the required sentence for monitoring on a laptop.

Basic Version

The Filter is also available as a powered splitter without any filtering.

And it doesn't stop there! The NMEA Filter 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 that the Filter works with. For further information or if you are looking for something similar please contact:-Eiland Communciations Limited  

Warranty Terms

August 3rd, 2008 09:22:32