I just purchased a new Furuno 1722C NavNet radar/chartplotter/GPS and a Simrad WP-30 wheelpilot. One of the things I am trying to do is get the autopilot to take waypoint data from the chartplotter. On the Furuno I have a cable running between the GPS antenna and the chartplotter/radar. This is supposed to be where other NMEA equipment is also interfaced. On the Furuno cable I have four wires carring signal information. It uses NMEA 0183 (?) v2.0. The four lines are TD-A (+), TD-B (-), RD-A, and RD-B. The Simrad has four wires also, NMEA +, NMEA -, and two Cirrus wires (for wind data). The question is, where do the two NMEA wires from the Simrad tie into the GPS cable? I have tried TD-A for NMEA + and TD-B for NMEA -, but the Simrad doesn't recognize the signal. Do I try the RD pair, or do I forget it because I can't link the autopilot this way? Thanks for any help. Les Murray s/v Ceilidh 86 C-36 #560
- Status
Don't give up the ship!
In NMEA parlance one device is the "talker" all others are "listeners" - in your case the GPS must be the talker, since it is sending information to the plotter and the autopilot. My guess is that TD stands for "Transmit Data", and RD stands for "Receive Data". Now the question is - on the Furuno side, does TD & RD refer to the plotter or the GPS? You need to connect the NMEA input on the autopilot to the output (TD) of the GPS - which must already be connected to the RD of the plotter. Now you are totally confused! Seriously, the output of the talker must be connected to the inputs of all the listeners. If RD refers to plotter input, you should connect those lines to the autopilot NMEA input. Also make sure that both systems are set up to communicate at the same speed. The default NMEA is 4800 baud. Another thought - Is the Furuno sending the NMEA sentences (data) that the Simrad can understand? Derek
In NMEA parlance one device is the "talker" all others are "listeners" - in your case the GPS must be the talker, since it is sending information to the plotter and the autopilot. My guess is that TD stands for "Transmit Data", and RD stands for "Receive Data". Now the question is - on the Furuno side, does TD & RD refer to the plotter or the GPS? You need to connect the NMEA input on the autopilot to the output (TD) of the GPS - which must already be connected to the RD of the plotter. Now you are totally confused! Seriously, the output of the talker must be connected to the inputs of all the listeners. If RD refers to plotter input, you should connect those lines to the autopilot NMEA input. Also make sure that both systems are set up to communicate at the same speed. The default NMEA is 4800 baud. Another thought - Is the Furuno sending the NMEA sentences (data) that the Simrad can understand? Derek
Furuno 1722
I took a look at the Furuno 1722C brochure on their web site (I'm interested in that unit myself) It looks to me as if the unit acts as a NMEA repeater, that is it takes data from the GPS on the RD lines, adds some sentences and puts it back out on the TD lines (including autopilot relevant information). It mentions a menu set-up - have you taken a look at the options there? - Derek
I took a look at the Furuno 1722C brochure on their web site (I'm interested in that unit myself) It looks to me as if the unit acts as a NMEA repeater, that is it takes data from the GPS on the RD lines, adds some sentences and puts it back out on the TD lines (including autopilot relevant information). It mentions a menu set-up - have you taken a look at the options there? - Derek
Debugging....
Here is what I would do: 1) Read the manuals. I know it's a radical suggestion, and one of last resort, but do it anyway
2) Check out the set-up menus on the Furuno to make sure it is set to transmit NMEA data. For example, on my Garmin there are several options that can be set on the communication ports - including being off. 3) Take a dc voltmeter, set to a low voltage, say 10v, and connect it across the TD lines while the unit is working. You should see the meter flicker up to 2-3v every two seconds or so as the unit transmits the NMEA data. If there is no voltage - check the set-up menu again. (I always use an analog voltmeter for this - digital DVMs may get confused by the data waveform). If you see the flicker you can be confident that data is being set. 4) Make sure the Simrad is set to recieve data. Derek
Here is what I would do: 1) Read the manuals. I know it's a radical suggestion, and one of last resort, but do it anyway
2) Check out the set-up menus on the Furuno to make sure it is set to transmit NMEA data. For example, on my Garmin there are several options that can be set on the communication ports - including being off. 3) Take a dc voltmeter, set to a low voltage, say 10v, and connect it across the TD lines while the unit is working. You should see the meter flicker up to 2-3v every two seconds or so as the unit transmits the NMEA data. If there is no voltage - check the set-up menu again. (I always use an analog voltmeter for this - digital DVMs may get confused by the data waveform). If you see the flicker you can be confident that data is being set. 4) Make sure the Simrad is set to recieve data. DerekDerek, you may be on to something with the menus
Derek, Thanks for the information. Trust me, I have read the manuals (all four of them). Trying to assimulate all the information is causing great confusion. I do remember on the GPS Port Setup where there was a setting for output. I currently have that set to NO. I may need to change that and describe the sentences that are sent out. As far as the unit itself, I think it is pretty good. I got the color version and it is pretty neat. You get a lot of functionality and flexibitly with the NavNet system at a lower price than most of the Raytheon stuff. A couple of things I have learned during the install. First, Edson does not make a compatable pod for the 1722 yet. I went with a Navpod 41 to get the right depth. Second, Edson also does not make a compatable mast mount for the raydome. For this, I am using the Scanstrut. I would have prefered a Quetus backstay mount, but I didn't have that much money to spend. Finally, if you are running a mast mounted radar with a cockpit mounted display on a 36 foot boat, you will need more than 30 meters of cable. I originally got a 20 meter cable and had to buy a 15 meter cable to run up the mast. Again, thanks for the input. Les Murray s/v Ceilidh '86 C-36 #560
Derek, Thanks for the information. Trust me, I have read the manuals (all four of them). Trying to assimulate all the information is causing great confusion. I do remember on the GPS Port Setup where there was a setting for output. I currently have that set to NO. I may need to change that and describe the sentences that are sent out. As far as the unit itself, I think it is pretty good. I got the color version and it is pretty neat. You get a lot of functionality and flexibitly with the NavNet system at a lower price than most of the Raytheon stuff. A couple of things I have learned during the install. First, Edson does not make a compatable pod for the 1722 yet. I went with a Navpod 41 to get the right depth. Second, Edson also does not make a compatable mast mount for the raydome. For this, I am using the Scanstrut. I would have prefered a Quetus backstay mount, but I didn't have that much money to spend. Finally, if you are running a mast mounted radar with a cockpit mounted display on a 36 foot boat, you will need more than 30 meters of cable. I originally got a 20 meter cable and had to buy a 15 meter cable to run up the mast. Again, thanks for the input. Les Murray s/v Ceilidh '86 C-36 #560
- Status