NN vx2 NMEA Out Issues - Is Port 2 dead? and Why does Port 4

[Anonymous]

Hi all. I'm new here to the forum. Great place I must say!

In my new boat, a 1988 Chris Craft 315 CDR, I just installed a new-to-me but used (still pristine) Navnet vx2 RDP-149 and have an issue with Port2 NMEA out and sharing the NMEA to two listeners on Port4. The smart antenna is plugged in to Port1 and the BBFF sounder is on the Network port. For now it all works great as a plotter and sounder. So far as I know the firmware has not been upgraded. I have a Sitex AP-110 and Standard Horizon Intrepid VHF to interface. Unfortunately, I am in Africa at work for a week more and can only ponder this mystery for now.

My 1st goal is to get position out to my VHF and route data out to my AP. (they both do NMEA0183) 2nd is to bring AIS data in to the plotter from my soon-to-be-bought Matrix VHF with AIS receive. I know I need to keep Port4 for the highspeed AIS data in to the plotter and Port3 is heading data in to the vx2 only. That leaves me with P2 and P4 to handle the VHF and AP out and AIS in. Sounds simple, right?

So when I hook up the white/black nmea-out wires of Port2, I only see a very slight tickle of voltage, like 0.05vdc on my fluke. With the proper data strings enabled, I see nothing on the port data screen for P2.

I then try them on the blue/white wires on Port4 and then I get the data, but only one at a time. And this is the port I know I need for AIS input later. So I hook up only the radio and the position shows. I switch the wires over to only the AP and I believe the route data is getting there as I see the strings advancing on the vx2 screen. Now I have yet to go out in the harbor to test this functionality, but I will be able to soon.

When I hook both Port4 NMEA out wires to the two pairs of VHF and AP wires and the position display on the VHF blanks out. Separate them listeners and the position comes back. I've tried reversing the AP wires but think I get the same results. (I've been gone for 3 weeks now)

My big fear is that I killed Port2 or not so bad that it was dead when I got the vx2. On the Sitex AP, there is a small red heading-out wire that comes off the back of the unit that can feed heading data to a device like a radar. I didn't check it for voltage, but it was waving around while I was trying different combinations and it could have briefly come in contact with some of the others... No, I don't recall any sparks or smoke!

Is there a way to test Port2 for the output other than what I have done? Or is there a super secret reset that I can do to revive things?

So the big mysteries are:

1) Is my Port2 NMEA out dead?

2) why can't I parallel two listeners (the AP and VHF) on the Port4 white/blue wires?

3) If Port2 is truly dead, can I solve this with a hub or maybe a multiplexer?

Scott Carter
San Diego CA

 

[C-Bass]

Good afternoon Captainsdc,

Thank you for your inquiry.

One thing that I would watch out for with respect for to the VHF radio is RS232 data vs. RS422. Sometimes manufacturers will say the VHF is NMEA0183 compatible but fail to mention the NMEA0183 inputs on their radios use a common ground similar to RS232 voltage levels. There could be an issue with different ground potential which in fact has been know to blow NMEA0183 transmitters. It would be recommened to find out if your radio does indeed use RS422 or do they use the common ground RS232 platform. If they use a common ground we recommend using an opto-isolator to keep your equipment safe.

Please remember when you look at the port monitor on the Vx2 that does not show you what data is being transmitted, the port monitor is only for in coming data.

I would recommend doing a loop back test on Port 2 to make sure that port can transmit and receive. Turn on data sentences like GGA and ZDA for port 2, next take the white and black wires and connect them to the yellow and green wires on port 2. White to yellow and black to green. Next open up the port monitor, you should see NMEA0183 ASCII text for GGA and ZDA. The data will come in one line at a time at 1 second intervals. The VX2 does not have a high speed output so the output data rate is Hz or 1 time a second.

If you have data showing on the port 2 monitor with this test it will tell you if that port can send and receive data. If you have data you should be fine. As I mentioned above I would verify the VHF radio does have a separate ground for the data lines, if it does not I would recommend an opto-isolator be installed when connecting to the VHF.

Please remember if you plan to bring in AIS data the baud rate will need to be changed to 38,400. When you change the baud rate of a port it will change both the input and output on that port. So if you plan to bring AIS data in on Port 4, you will need to change to 38,400. When doing so if you plan to connect the output wires to your radio and
autopilot they will have to work with a 38,400 baud rate.

You should be able to connect both the VHF and autopilot to a single port but please keep in mind the radio is really only looking for position data and time. Where the autopilot will need data such as APB, RMB, RMC, GGA or GLL, and ZDA. Sometimes the radio may not like all the extra data that is being sent out. If that is the case you could use a NMEA 0183 expander. MOXA, Noland, and Actisense all make nice boxes that are reasonably priced.


Kind Regards,

C-Bass

 

[Anonymous]

Thanks for that quick response. I still have a few follow on questions. Well, more than a few...

That loopback check sounds simple and I’m anxious to get home to try it. About the rs422, I checked the radio and AP manuals and see only mention of 0183 so that should be it. I've checked the accessory cable pinout page from the radio and it does have the two different wire pairs for in/out. Will the vx2 take position data and display it with the DSC polling function? I used it on another boat that had all Standard Horizon gear. Good stuff.

Last month I had both of the vx2 Port1 and Port4 wires (stripped) in the same vicinity when I was trying things with the radio and AP and was not seeing what I had hoped. Could the power wire on P4 have possibly caught one of the wires on P2 and killed it? I surely hope not. If so, is that repair to the nmea transmitter a monster job or doable? I'm pretty good with circuit repair, but I imagine this being Japanese it is probably something only a shop would try if that. Is it a crazy thing to attempt - either me or you?

And if I find the P2 is dead, how can I get these 3 devices (VHF/AP/AIS) connected with only Port4? I don’t think using a hub will allow putting the antenna into it and therefore opening up Port1 so i could use P1 and P4 for NMEA0183 at both speeds? It has to go on P1, right? If so, can I combine the nmea data from the 3 units and put it in P4 with a nmea multiplexer or similar at the speeds right for the AIS data?

In my initial attempts to interface the radio and AP, I did limit the sentences like you said (only either GGA for the radio and BOD/XTE on the AP) to keep the traffic minimized and be sure I was seeing/getting it where I wanted it. Setting the few more or less AP sentences to on didn't seem to make any difference in the VHF dropping the position. But could it just take one extra sentence to crash the radio position?? Since the AP is a listener only, that shouldn’t interact with the listening radio NMEA in, right? It has me wondering...

You mention that the port data viewer only shows data coming IN to the vx2. But I recall seeing the data only when the wires with connected, meaning to me that the port was handshaking and the radio receiving the output from the vx2. I'm sure I wasn't looping it back, but I guess maybe I don't quite get it.

Well, I guess that was a little more than a few. Hoping to hear some clarifying stuff!
Scott

 

[Anonymous]

It's still a handful of days until I get home and dig in to see what's up with Port2 on my vx2.

But I just now remembered something that may be telling about what happened. On one of the reboots I did while testing to see if I had Port2 putting out data to the AP/VHF, I saw not the regular reboot screen. It came up with a full new restart screen asking the language, etc, like it was fresh out of the box. All my marks and routes were wiped and I also recall the boot screen looks different than before I started messing with the nmea interfacing with P2 and P4. I had obviously pissed it off!

Does this perhaps explain maybe why Port2 wasn't showing and output voltage when I thought it should be?

 

[C-Bass]

Good morning CaptainSDC,

It sounds like the unit went through the Master Reset cycle. Which may have turned off all your NMEA sentences. We ask when you return to your home port to try the loop back test and let us know what you find out.

If the port does not get any response after you try the loop back test you have a couple options. You could take the unit to one of our authorized dealers in your area for further evaluation and repair. You could also send the unit into our national service center located in Washington State for evaluation and repair.

It would be difficult to get all three devices in and out of one port. You could have a couple options by using a multiplexer/port expander. You could also use port 1 output if you wanted to cut the GPS cable and break it out into a terminal strip. Remember the AIS requires 38,400 baud. So if you decide to try and use 1 port you need to make sure your other devices can handle the higher baud rate.

The port monitor only shows data that is coming in. It is a nice feature to verify what you are seeing from another device that transmits NMEA0183.


C-Bass

 

[Anonymous]

OK thanks. I believe I recall the sentences were still all assigned as before the reset. So does that make sense if I somehow fried Port2, it could have cause it to go to a master reset? I also seem to recall the Matrix VHF/AIS manual (not yet purchased) said it can combine the output for polling and data in to the higher speed. so Maybe I can use P4 for the radio and AIS. But that will still leave my AP hanging unless I use a multiplexer, right?

 

[Anonymous]

Good morning CaptainSDC,

It sounds like the unit went through the Master Reset cycle. Which may have turned off all your NMEA sentences. We ask when you return to your home port to try the loop back test and let us know what you find out.

If the port does not get any response after you try the loop back test you have a couple options. You could take the unit to one of our authorized dealers in your area for further evaluation and repair. You could also send the unit into our national service center located in Washington State for evaluation and repair.

It would be difficult to get all three devices in and out of one port. You could have a couple options by using a multiplexer/port expander. You could also use port 1 output if you wanted to cut the GPS cable and break it out into a terminal strip. Remember the AIS requires 38,400 baud. So if you decide to try and use 1 port you need to make sure your other devices can handle the higher baud rate.

The port monitor only shows data that is coming in. It is a nice feature to verify what you are seeing from another device that transmits NMEA0183.
C-Bass

Well, I am back at work, having just spent 3 weeks at home, all but two days messing with the boat! M list is down to about 4 things now and I am super glad that the plotter isn't on that list any more.

The short story is that the ports are doing what they should and the Port2 cable had an intermittent break inside at the strain relieve by the connector :shock: . Uh, yea, that's the one I thought worked before and then didn't. It's pretty embarrassing how many things I tried so many times before I decided to inspect the pins and that't when I saw the voltage come in and out while bending the wire. Port4 was showing about 12 volts and Port2 about 4v fluctuating with the NMEA output as expected. So changing the cable solved my Port2 issue! I hooked up the autopilot and radio and they worked just fine.

Oh yes, the SH radio did use the common ground trick so I ended up only hooking one of those wires (+) to the plotter Port2 in wire and the (-) NMEA wire to ground.

Yea! :jump I get to call this a win; my plotter port wasn't dead after all!!

One thing that didn't work has me SMH. The port loop back test didn't work on either Port2 or 4. I tried the g-y in/w-b out wires both ways and never saw a hint of the usual text data streaming. The only time I saw anything at all when on the Port2 monitor screen when I connected the radio in to the plotter wires for a moment and I got a line or two of jibberish (before finding the bad wire) and so I knew the port was alive likely doing its thing. Same thing with Port4, but I have left that cable disconnected until I get my VHF/AIS unit. Perhaps I needed to have the connection made and reboot the machine to establish the link? That doesn't make sense, but maybe, huh?

Either way, the ports are porting so I am good to go.
Thanks again to the mods and users of this forum.
:furuno

 

[Anonymous]

I will be sending in my other vx2 tomorrow and need an RMA. I found there is a bad Network board where the DFF1 plugs in. A local tech here in SD has helped me ID it and he doesn't have any parts that I could buy to swap and test things with. Cables and the DFF1 have also been changed and checked. So It is hitting the mail (UPS?) but I need the RMA.

Scott

 

[C-Bass]

Good morning Scott,

You do not need a RMA to return the unit for service work. Please write a small note about the issues that you have seen and diagnosed and include that in the package with your unit, please also provide your current contact information. Please also make a note to advise and contact before fixing.

Furuno USA
ATTN: Service
4400 NW Pacific Rim Blvd
Camas, WA 98607



C-Bass

 

[Anonymous]

I need this radar back asap. What's the best way to ship it and expedite the return?

 

[Johnny Electron]

If it comes in UPS red, they normally know that it is a priority, but you should also explain the urgency in your letter.

 

[Anonymous]

I did it FedEx Wednesday delivery. The included description does indeed ask for expedition. I'm available on cell to consult to decide what needs to be done. Tks.

 

[Johnny Electron]

You can contact the repair center at 360-834-9300 if you need to follow up with them on status.