Hi All,

PV780 and PowerVision 2.7.10475

Fast Packet works if I set a system/function ID or a Source Address. 8 bytes NMEA works if I set 255 as Source Address.

Now to the problem I have:
I want to recive NMEA Fast Packet with 255 (any SA) set as Source Address but this will not work. Why is this? I hope this is a bug in the display sw and not a limitation in NMEA spec.

Any thoughts on this issue?
Thanks in advance!

/Joakim

Hello Joakim,

I created an NMEA device with a Source Address of 255, then put the 127489 PGN with Total Engine Hours parameter at bytes 12-15 on the device. The Fast Packet is checked in the Library.

My data is for instance 0, so that might have an effect on what the display receives, but it does receive and display the Total Engine Hours.

Is this the situation you have?

Hi,

That is exacly how my PGNs are setup. We are supporting a total of four Engine devices so I have them on instance 0-3. All 8 byte PGNs are received, no problem there. FastPacket are setup exactly the same way except FastPacket box checked. One of them are PGN 127489.

I have done some more tesing and I was a bit wrong in my first post. FastPacket don´t work for my engine devices even if I set a Source Address on the device. Tested to send FastPacket from another PV780 and that is received. Tested receving FastPacket from a GPS and that works. Both with static SA or SA set to 255 or if you use system/function ID. So, the PV780 can receive FastPacket but not from my engine devices. I´m thinking now that this could this be frame timing issue?

Engine device outputs frames with 100ms time time diff and complete PGNs is on 500ms like it should be for PGN 127489. The GPS and the PV780 outputs frames with 1ms diff.

Both should be ok to me if you read the NMEA spec:
* Fast-packet messages of the same PGN may be transmitted at intervals of less than 100 ms, see ISO 11783-3 Table 5.
* Successive fast-packet frames may be transmitted without additional inter-frame delays.
* A fast-packet message shall not be considered as incomplete until a time-out of 750 ms from the last received frame occurs.

So the only thing I can see that is different is the timing issue! Will test one more thing and that is to speed up time between frames from engine device but that involves the EMS supplier and I don´t know when this could be done.

Can you tell me how PV780 is setup? If it could be a time-out occuring?

Thanks, Joakim

Hello Joakim,

The PV780 doesn't care about the timing of received packets as long as the addressing and the spns in the database are correct.

Do you have a recording of the data from the ECU? It might be that the ECU is sending it as a different instance or something.

You probably need a different PowerVision device for each instance.

Ok,

Then I can´t figure out why this isn´t working for me. I will post some CAN-dumps tomorrow when I´m back at work and maybe you can see something that I have missed. :)

Thanks!

Actually I had some CAN-dumps on this computer...

This one works and is coming from one PV780 to another PV780:
Prio PGN SA DLC D0 D1 D2 D3 D4 D5 D6 D7 Time
2 1F201 F2 8 0 1A 0 0 0 0 0 0 11756,06041
2 1F201 F2 8 01 0 0 0 0 0 0 0 11756,06109
2 1F201 F2 8 02 0 0 0 0 0 0 0 11756,06169
2 1F201 F2 8 03 0 0 0 0 0 0 FF 11756,06237
2 1F201 F2 8 40 1A 0 0 0 0 0 0 11756,55654
2 1F201 F2 8 41 0 0 0 0 0 0 0 11756,55714
2 1F201 F2 8 42 0 0 0 0 0 0 0 11756,55773
2 1F201 F2 8 43 0 0 0 0 0 0 FF 11756,55833
2 1F201 F2 8 60 1A 0 0 0 0 0 0 11757,0606
2 1F201 F2 8 61 0 0 0 0 0 0 0 11757,06129
2 1F201 F2 8 62 0 0 0 0 0 0 0 11757,06197
2 1F201 F2 8 63 0 0 0 0 0 0 FF 11757,06257

This one doesn´t work coming from ECU to the PV780:
Prio PGN SA DLC D0 D1 D2 D3 D4 D5 D6 D7 Time
2 1F201 0 8 0 1A 0 0 0 E5 FF 18 43381,97958
2 1F201 0 8 1 5B C2 4 FF FF A5 9B 43382,07955
2 1F201 0 8 2 C4 20 FF FF FF FF FF 43382,17951
2 1F201 0 8 3 0 0 0 0 FF FF FF 43382,27955
2 1F201 0 8 20 1A 0 0 0 E5 FF 18 43382,47942
2 1F201 0 8 21 5B C3 4 FF FF A5 9B 43382,57939
2 1F201 0 8 22 C4 20 FF FF FF FF FF 43382,67935
2 1F201 0 8 23 0 0 0 0 FF FF FF 43382,77939
2 1F201 0 8 40 1A 0 0 0 E5 FF 18 43382,97926
2 1F201 0 8 41 5B C2 4 FF FF A5 9B 43383,07923
2 1F201 0 8 42 C4 20 FF FF FF FF FF 43383,17919
2 1F201 0 8 43 0 0 0 0 FF FF FF 43383,27923


Now you have all night figuring this out! :)

Hello JoakimMD,

Traffic data looks essentially the same. The first three bytes of the first message match up, so that looks ok.

Since the PV780 is receiving J1939/NMEA 8 data byte messages from the ECU, the 120ohm resistance is ok.

When you tested transmitting from a PV780, did you transmit the hours or some parameter after the first 8 bytes? Maybe you just thought it was working, maybe?

Hi Sara

Sending you a PDF and Excel with more info in email.

PDF Page 1: Blue CAN-bus is where I look at 1F201 from ECU. Red CAN-bus is PV780 to PV780. Reason for this connection is that I can at the same time test our “CAN Gateway” function. This will be used if customer wants to connect their sea chart plotter an show engine data.

PDF Page 2: As you can see the PV780 on the right have invalid gauges meaning no data received. On the left PV780 the gauges is active but no data because right PV780 is not receiving from ECU.

And yes, another test that I did was sending data also. Did a custom software where I could change a parameter to see if gauges changed on the left PV780 and that was OK.

Both PV780 is having the same software.

/Joakim