Hello Luis,
On my old boat, I have an old Furuno brand sounder, FCV 668.
It has an NMEA output that allows me to recover data.
The system works, I'm getting this data on OpenCPN, for example.
These NMEA data, according to Furuno's documentation, are of this type:
(nmea output of the sounder)
1 = td-h
2 = td-c
3 = rd-h
4 = rd-c
td in nmea = transmit data
c = cold / common / -
h = hot / high / +
In this case too (as for the arduino), I think that there is a problem with the optocoupler that requires an intensity on A1 (that maybe does perhaps not deliver the Furuno).
How to "shunt" the optocoupler so that Furuno's NMEA sentences can be read ?
Best regards
AlainS
P.S. I'm sorry to give you extra work, but maybe it will help other users as well ...
Furuno Sonar
Re: Furuno Sonar
Hello Alain,
I just finished an answer on the other post. The other post refers to "Arduino >>> Multiplexer" connection. Before I refer to the Furuno, I emphasize that the Arduino serial transmission on the TX pin is not Nmea 0183 compatible. TX is HIGH when the Arduino is idle!
The Furuno output is Nmea 0183 compatible. So its transmitting pin td-h should be LOW when the Furuno is idle! I do not think the intensity current demanded by the multiplexer is the problem. By the contrary. The Furuno output should give a signal of 5V at least. Taking 1V2 for the LED, you get 3V8 across the 2K2 resistor or 1.7mA (3.8/2.2). This is a very lower current! I wonder if you have an oscilloscope!
I will leave this message now and I will try to read the FCV 668. By the way (how do you connect the Furuno to the PC or tablet that runs OpenCPN?)
Best Regards (and it is a pleasure to discuss electronic problems!), Luis
PS: you can "remove" the optocoupler but then you need an inverter!
I just finished an answer on the other post. The other post refers to "Arduino >>> Multiplexer" connection. Before I refer to the Furuno, I emphasize that the Arduino serial transmission on the TX pin is not Nmea 0183 compatible. TX is HIGH when the Arduino is idle!
The Furuno output is Nmea 0183 compatible. So its transmitting pin td-h should be LOW when the Furuno is idle! I do not think the intensity current demanded by the multiplexer is the problem. By the contrary. The Furuno output should give a signal of 5V at least. Taking 1V2 for the LED, you get 3V8 across the 2K2 resistor or 1.7mA (3.8/2.2). This is a very lower current! I wonder if you have an oscilloscope!
I will leave this message now and I will try to read the FCV 668. By the way (how do you connect the Furuno to the PC or tablet that runs OpenCPN?)
Best Regards (and it is a pleasure to discuss electronic problems!), Luis
PS: you can "remove" the optocoupler but then you need an inverter!
Re: Furuno Sonar
Hello Luis,
I am less than a beginner in electronics so I do not have an oscilloscope.
Previously, I had connected the Furuno sounder to the PC / OpencCPN with a "USB to RS232 Serial Converter" cable.
I then did tests with the arduino mega as a multiplexer, but I do not find any traces in my notes of the Furuno's connection (all other instruments were well connected).
I will test this WE the Furuno alone with a mega arduino connected to the PC directly.
In the meantime, I am attaching an installation manual of the FCV668, there is a schematic diagram in the last pages.
Best regards,
Alains
I am less than a beginner in electronics so I do not have an oscilloscope.
Previously, I had connected the Furuno sounder to the PC / OpencCPN with a "USB to RS232 Serial Converter" cable.
I then did tests with the arduino mega as a multiplexer, but I do not find any traces in my notes of the Furuno's connection (all other instruments were well connected).
I will test this WE the Furuno alone with a mega arduino connected to the PC directly.
In the meantime, I am attaching an installation manual of the FCV668, there is a schematic diagram in the last pages.
Best regards,
Alains
Last edited by schnapsy on Mon Apr 15, 2019 2:22 pm, edited 1 time in total.
Re: Furuno Sonar
Another clarification concerning the connection of the Furuno to the PC / openCPN.
Before knowing your system (efficient, detailed and affordable), I had bought another multiplexer (I do not give the address here).
This small multiplexer works well, it is powered by 12V and has 3 configurable inputs - a single wire each time - (from 4800 to 38400 bds) and three outputs.
The setting is more complicated than for the NMEA4Wifi, but I had only to connect to this multiplexer a single wire from the Furuno sonar and the NMEA frame was sent to the PC, with the other NMEA sentences.
Best regards,
Alains
Before knowing your system (efficient, detailed and affordable), I had bought another multiplexer (I do not give the address here).
This small multiplexer works well, it is powered by 12V and has 3 configurable inputs - a single wire each time - (from 4800 to 38400 bds) and three outputs.
The setting is more complicated than for the NMEA4Wifi, but I had only to connect to this multiplexer a single wire from the Furuno sonar and the NMEA frame was sent to the PC, with the other NMEA sentences.
Best regards,
Alains