Actisense/SimNet

[Playtime]

I have a SimNet N2K network connected to a laptop down below for monitoring/logging via an Actisense N2K to USB converter.

The SimNet has an NSS8 chartplotter plus IS20 wind, speed and multi instruments.

When the NSS8 is off but SimNet and the instruments are on, I can receive all expected data on the laptop. In particular, the DBT and DPT sentences for depth are both received.

However, when I turn on the NSS8 the depth info disappears from the laptop - only the DPT sentence is received and this does not contain any useful info. This is disappointing as I would normally have the NSS8 powered up when sailing and the laptop would be keeping a running data log including depth.

I have the latest versions of software on both the Actisense and NSS8.

I have raised the problem with Simrad Support but so far no answer. I will also try contacting Actisense

Has anyone any experience of this set up or thoughts about the possible cause?

 

[Playtime]

Fifty Views but no response, as of 1730.

Let's try one more time from the top and see if Monday has any experts viewing!

 

[maby]

Fifty Views but no response, as of 1730.

Let's try one more time from the top and see if Monday has any experts viewing!

Only just read your post - have you checked the network status for errors? I had similar issues (though with significantly different hardware) when I had the network termination cocked up. Depending on what was turned on, other things stopped working. There is probably a network status screen hidden somewhere deep in the NSS8 menus which will tell you about any transmission or receprion errors. May well be something similar on the Actisense screens.

 

[Playtime]

Only just read your post - have you checked the network status for errors?

No but I will.

The network was originally installed by the builder. I have only added a spur with the ActiSense unit at the end so it should be OK. However, my addition is via a 4m cable so will have had some affect on the overall network loading.

 

[knuterikt]

No but I will.

The network was originally installed by the builder. I have only added a spur with the ActiSense unit at the end so it should be OK. However, my addition is via a 4m cable so will have had some affect on the overall network loading.

So you added a T-Piece for the spur cable and moved the terminator to the side oposite to the backbone cable?

 

[Playtime]

So you added a T-Piece for the spur cable and moved the terminator to the side oposite to the backbone cable?

No - I added a new spur to an existing 5 way junction. I haven't disturbed either terminator.

I checked this afternoon on the Network Diagnostics screen on the NSS8 and there were no errors so I don't think it's a network problem.

I have made contact with Actisense and they are being helpful. I have now sent them a log file of the network messages received (0183 converted) with the NSS8 Off, then On, then Off again. It clearly shows the DBT sentence disappears while the NSS8 is On and reappears when it is turned Off.

What we want to know is why!

Simrad Support are, so far, remaining silent. Once I have completed my dialogue with Actisense Support I will phone them and see what thoughts they have.

It would be helpful to log the actual PGNs on the network but unfortunately I don't have the necessary interface.

 

[geoid96]

Is your Actisense outputing NMEA 0183 at the default 4800 baud? If so, the maximum number of standard messages that can be sent is 6 per second. It's possible that switching on the NSS8 increases number above this and the DBT is dropped. You could try increasing the baud rate to say 9600. (See page 9 of the NGW-1 manual).

 

[Playtime]

Is your Actisense outputing NMEA 0183 at the default 4800 baud? .

Baud rate is set to 38400. Receive loading is shown as a few percent, so OK.

 

[Playtime]

I've managed to get ActiSense Support interested in this problem. After providing them with a couple of log outputs, they have concluded as follows -

"It looks like the NSS8 has a depth sounder capability and is outputting DPT.
If the NSS8 has a lower address than your actual sounder, the NGW-1 will use the lower address as priority.

There should be an option in the NSS8 to disable the depth output."

My depth transducer is an Airmar Smart Tri (DST200) which outputs the 128267 PGN (and others) directly onto the SimNet bus and this is read and interpreted correctly by the ActiSense Converter (NGW-1) when the NSS8 is off. However, when the NSS8 is on, the NSS8 sends out its own version of 128267 and this is used by the NGW-1 if it is higher priority than the transducer. Because the NSS8 has no analogue transducer connected to it there is no depth info included in the NSS8 version of 128267, only the depth offset info which is preset. This then converts (in the NGW-1) to DPT only without any depth info - hence my original problem above.

If this theory is correct, does anyone know how to disable the NSS8 internal depth sounder function so that the 128267 PGN from the transducer is not overridden? Alternatively, does anyone know how to alter the address of the NSS8 on the bus to lower it's priority and allow the transducer PGN to be higher priority?