Navmon & PCPlotter

[cliveshelton]

I have finally finished setting up a new Sumvision 12V PC fed by nmea from a MUX (actisense) and receiving everything nicely including AIS from our nav instruments. Deep joy (for those of us keen on these things of course). Output is to a 12V TV (Avtex).

My next step is to get all that out onto a wifi network of some kind (yes I know its been done to death on here but I will enjoy experimenting).

What I want to do is to load and run a nmea file with NavMon and play it into PCPlotter as the source of data whilst I am at home sorting it out. I have managed that with OpenCPN but I prefer PCPlotter and its not cooperating.

I use Windows 10 + GpsGate to create virtual com ports (apparently that is necessary with W10). In OpenCPN you simply point the nmea input to the correct port. In PCPlotter a similar choice of port etc. does not work.

Any ideas?
Thanks.

 

[bitbaltic]

Would you believe it I have just been through EXACTLY this sequence of events with almost exactly the same hardware and software. I also have an explanation (that you will not like very much) and a solution (that you will probably like even less).

I have the Windows 10 Sumvision Mini PC and it gets its NMEA feed from a Shipmodul USB multiplexer. Last season I used NavMonPC to connect to the USB/physical COM port and used NavMon to distribute the NMEA data to several other programs, including Meridian's SeaTrak as a plotter, via virtual COM ports. As you say NavMonPC uses drivers from Franson GPSGate to create these virtual ports. I had no problems with this setup last season at all.

This season I installed a cockpit chartplotter using Navionics charts and thought, wouldn't it be nice to be able to use them on the PC below too. So I bought PC plotter because it can handle the Navoinic vector charts and is a lot cheaper than other solutions e.g. Expedition/SeaPro/Adrena.

I brought the Sumvision home from the boat to update etc over the winter and also install PC Plotter and the Navionics charts. All installed fine and in order to bench-test the system at home (the actual source of NMEA, ie the multiplexer, obviously being on the boat) I tried to play back an NMEA file from NavMon to PC Plotter via a virtual COM established using the GPSGate drivers. Result, exactly as you have found- it does not work. PC plotter knows the virtual COM port is there and that it is connected to it (you are able to select it as 'possibly some GPS or other' in the drop-down settings box for NMEA-1) but PC Plotter keeps saying 'No NMEA' in the vessel position box, and nothing you do makes any difference.

I suspect the above is eerily familiar to you.

I spent a total of six weeks to-ing and fro-ing this with Yachting Software (who are the retailers/'makers' of PC Plotter) and Future Data International (FDI herein) (who are the actual programmers/coders responsible for it).

FDI tell me that PC Plotter uses something called 'overlapping I/O' as a protocol for reading and writing data to and from COM ports, whether virtual or physical. This involves using some bit of ?coding called the EV_RXFLAG which FDI say is the most professional and reliable way to read and write data to a COM port. Trouble is, lots of other software coders- including Franson and GPSGate- don't implement (or don't need to implement) this flag, and PC Plotter is unable to talk to any port which doesn't implement it. Basically, the software won't talk to COM ports from the cheap side of the street, and because FDI regard non-EV_RXFLAG implementations as poor software engineering, they are unwilling to make any changes to allow it to do so.

So to cut a long story short, PC Plotter will not talk to Franson/NavMonPC virtual ports whatever you do.

So much for the explanation. Here's the solution.

FDI's final (and in fact only) suggested solution does work. It is to buy a different bit of software with which to create virtual COM ports, from a company called Eltima; they make several virtual port enablers which iplement the EV_RXFLAG code and the one that suited my needs best was Serial Port Splitter, http://www.eltima.com/products/serialsplitter/.

I installed Serial Port splitter and used it to split the physical multiplexer port into virtual COM ports feeding both NavMonPC and PC Plotter as well as several other things. It works fine, with the exception that the software occasionally loses the split mapping and it has to be re-mapped (well, it is a PC after all). The only fly in the ointment is that the Eltima software is an extra 90 QUID (inc VAT) for something that NavMonPC provides for free.

I can't complain about the support from FDI which was excellent (less so from Yachting Software- the issue went over their heads and there was some delay in putting me in touch with FDI so we could make progress). However I did make the point that, of the perhaps few marine PC users trying to create virtual ports, the vast majority are likely to be trying to use NavMonPC to do it, and that their software is not compatable with this (in point of fact, FDI had never heard of either NavMonPC or Franson) is not ideal.

The experience was a bit like going to John Lewis to buy a fantastic telly (PC Plotter)- the best engineered telly on the market, only to discover that, when trying to hook it up to a DVD player with a cheap HDMI lead (NavMonPC), it wouldn't work.

"you see sir, this telly is the best engineered TV on the market, so it can't be hooked up to your dvd with just any old lead, sir... you'll need this super-duper gold plated lead if you want to play a DVD on it, sir. Sorry, sir? Well, nobody's ever wanted to play a DVD on this telly before that I know of, sir. The gold HDMI lead, sir? well, that'll be a further 90 pounds, sir". Sounds stupid, doesn't it.

Anyway, the bottom line is that for any users wanting to run PC Plotter in a virtual COM environment on their onboard PC, the £120 headline rate is actually £90 short of the actual cost to achieve this as you will need to use the Eltima software to create your virtual COM network instead of Franson.

I have a stack of support emails and contact addresses for this so if you need anything more feel free to give me a PM.

Cheers

 

[cliveshelton]

Wow! Isn't this place fabulous. You've saved me so much time with your research and a beautifully explained work around. As it happens, I consider PCP the best of the bunch (the tide planning in particular) and will copy your solution immediately. I am happy to spend the extra so that I can maintain the connectivity with PCP. Many many thanks.

 

[bitbaltic]

More than welcome. In truth the Eltima software means the PC runs very well and is easy for crew to use- you just install it, set up the split and forget it (as I say, you might occasionally need to re-configure but hey). It runs in the background for every session thereafter, so there is no need to start any given piece of software in order to initialise virtual ports at the start of the session (as you would have to do with NavMonPC for instance). All crew need to do is open whichever bit of software they need to see and that software just has the NMEA stream, simples.

I expect my above post leaks a bit of the frustration that builds up over a six-week period when the final solution is to liberate more notes from the cruising budget.... agree however that PCP is a smart bit of software. FWIW I think the tide planner in SeaTrak is better though.

Drop me a line if you have any issues and I'll help if I can.

Cheers