Which new instruments

I asked the guy about it saying in the manual that the I70s transmits a load of PGNs. He waffled about it sending these PGNs to the ITC-5. Can this be right?! I would have thought the calibrations would be sent in a proprietary format. And as you say you haven't seen 2 values on the network. So this isn't clear at all!

My suspicion is that PGN126208 is used for calibration. Standard PGN but clearly one manufacturer's kit isn't going to understand what another manufacturer puts in it. But other than needing a display to correspond to each manufacturer's transducer, the main PGNs are much more tghtly defined than the 0183 equivalents so should be understood across manufacturers.

126208 NMEA - Request group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Complex Request Group Function Code
2 Requested PGN
3 Transmission interval
4 Transmission interval offset
5 Number of Pairs of Request Parameters to follow
6 Field number of first requested parameter
7 Value of first requested parameter
8 Variable Number of fields, Field number 6 repeated
9 Variable Number of fields, Field number 7 repeated

126208 NMEA - Command group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Command Group Function Code
2 Commanded PGN
3 Priority Setting
4 Reserved Bits
5 Number of Pairs of Commanded Parameters to follow
6 Field number of first commanded parameter
7 Value of first command parameter
8 Variable Number of fields, Field number 6 repeated
9 Variable Number of fields, Field number 7 repeated


126208 NMEA - Acknowledge group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Acknowledgment Group Function Code
2 Requested or Commanded PGN # being acknowledged
3 PGN error code
4 Transmission Interval / Priority error code
5 Number of Requested or Commanded Parameters
6 First parameter error code
7 Variable Number of fields, Field number 6 repeated

126208 NMEA - Read Fields - group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Complex Request Group Function Code
2 PGN Number
3 Manufacturer's Code
4 Reserve Bits
5 Industry Group
6 Unique ID
7 Number of pairs of Commanded Parameters Fields
8 Number of pairs of Fields to Read
9 Field Number of first Commanded Parameter
10 Value of first Commanded Parameter
11 Variable Number of fields, field 9 repeated
12 Variable Number of Fields, field 10 repeated
13 Field Number of first Field to Read
14 Variable Number of Fields, field 13 repeated

126208 NMEA - Read Fields Reply - group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Complex Request Group Function Code
2 PGN Number
3 Manufacturer's Code
4 Reserve Bits
5 Industry Group
6 Unique ID
7 Number of pairs of Commanded Parameters Fields
8 Number of pairs of Fields to Read
9 Field Number of first Commanded Parameter
10 Value of first Commanded Parameter
11 Variable Number of fields, field 9 repeated
12 Variable Number of Fields, field 10 repeated
13 Field Number of first Field to Read
14 Value of first Field to Read
15 Variable Number of Fields, field 13 repeated
16 Variable Number of Fields, field 14 repeated

126208 NMEA - Write Fields - group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Complex Request Group Function Code
2 PGN Number
3 Manufacturer's Code
4 Reserve Bits
5 Industry Group
6 Unique ID
7 Number of pairs of Commanded Parameters Fields
8 Number of pairs of Fields to Written
9 Field Number of first Commanded Parameter
10 Value of first Commanded Parameter
11 Variable Number of fields, field 9 repeated
12 Variable Number of Fields, field 10 repeated
13 Field Number of first Field to be Written
14 Value of first Field to be written
15 Variable Number of Fields, field 13 repeated
16 Variable Number of Fields, field 14 repeated

126208 NMEA - Write Fields Reply - group function
Field # Field Description
The Request / Command / Acknowledge Group type of function is defined by first field. The message will be a Request, Command,
or Acknowledge Group Function.
1 Complex Request Group Function Code
2 PGN Number
3 Manufacturer's Code
4 Reserve Bits
5 Industry Group
6 Unique ID
7 Number of pairs of Commanded Parameters Fields
8 Number of pairs of Fields to Written
9 Field Number of first Commanded Parameter
10 Value of first Commanded Parameter
11 Variable Number of fields, field 9 repeated
12 Variable Number of Fields, field 10 repeated
13 Field Number of first Field to be Written
14 Status of first Field Written
15 Variable Number of Fields, field 13 repeated
16 Variable Number of Fields, field 14 repeated

There is also:

126998 Configuration Information
Field # Field Description
Free-form alphanumeric fields describing the installation (e.g., starboard engine room location) of the device and installation notes
(e.g., calibration data).
1 Installation Description, Field 1
2 Installation Description, Field 2
3 Manufacturer Information, Field 3
 
Last edited:
Ok great we are getting somewhere....

On panbo he mentioned some displays calibrating in the display. And b&g have told me this for the triton for speed.

Also some systems have multiple speed calibration for log speeds. I think the dst800 supports this. But again not clear where different manufacturers keep this......

Really i am now thinking I want a system where none of the calibration is stored in the display at all......

So next to delve down into log speed calibration!!

I am not going to give up til i understand this.....
 
The DST800 must store the offset setting internally. It does make sense that the displays will only send those settings to recognised transducers. I have two Garmin GMI10s in the cockpit and a Raymarine badged DST800. I set the offset using one of the GMI10s and it shows correctly on both displays. It also shows correctly on my laptop, using OpenCPN, after the N2K data has been converted to MNEA 0183 and broadcast by wifi.
 
The DST800 must store the offset setting internally. It does make sense that the displays will only send those settings to recognised transducers. I have two Garmin GMI10s in the cockpit and a Raymarine badged DST800. I set the offset using one of the GMI10s and it shows correctly on both displays. It also shows correctly on my laptop, using OpenCPN, after the N2K data has been converted to MNEA 0183 and broadcast by wifi.

Good stuff. Have you ever tried calibrating the speed?
 
Also I think the speed and depth might be different. The depth pgn has a separate offset field i think. The speed doesn't. So it is possible it works differently.....
 
The DST800 must store the offset setting internally. It does make sense that the displays will only send those settings to recognised transducers. I have two Garmin GMI10s in the cockpit and a Raymarine badged DST800. I set the offset using one of the GMI10s and it shows correctly on both displays. It also shows correctly on my laptop, using OpenCPN, after the N2K data has been converted to MNEA 0183 and broadcast by wifi.

Interesting. The DST800 is an Airmar product so presumably they present the same interface to all vendors who re-badge it, so the configuration commands sent by various vendors' displays should be pretty similar. A theory at least.
 
There's a lot of interesting detail on how calibration works in the technical manual for the DST200; I'd assume the DST800 will function in a similar manner.

http://www.airmartechnology.com/uploads/installguide/DST200UserlManual.pdf

Thanks for that. So it is possible to write the speed calibration to the sensor by the looks of things as it has a table to keep it in.

Its weird that b&g support told me that tve triton2 doesn't do that.....!

Garmin told me they do.

Trouble is I don't really trust any of them. I would rather see it written down!
 
Thanks for that. So it is possible to write the speed calibration to the sensor by the looks of things as it has a table to keep it in.

Its weird that b&g support told me that tve triton2 doesn't do that.....!

Garmin told me they do.

Trouble is I don't really trust any of them. I would rather see it written down!

I have a complete Garmin N2K system (820 plotter, DST800 triducer, GHC20 autopilot, 3x GMI20 displays, GWS10 wind, GMR18 radar). Admittedly I haven't deeply investigated the menu options, but I'm not aware of any calibration for boat speed. However, I can attest that the whole lot works flawlessly and is extremely user-friendly. Also, updating is child's play, just download the update from the Garmin website on to a memory card, pop it in the plotter, and it automatically updates every item on the network.
 
Thanks for that. So it is possible to write the speed calibration to the sensor by the looks of things as it has a table to keep it in.

Its weird that b&g support told me that tve triton2 doesn't do that.....!

Garmin told me they do.

Trouble is I don't really trust any of them. I would rather see it written down!

There seem to be different versions of the DST800. The Raymarine one which was used with an ITC-5 is not 'smart', but there are 'smart versions of it - I guess they now sell the smart one in the latest packs as they connect to the network not to the ICT-5. I think there is also an 0183 version. So, the different manufacturers may give you different information, but it is possible for them all to be correct.

edit - pipped to the post.
 
If you look at the BandG website the transducers are described as smart or not. There is a clue there ;-)

I am aware of that. But how do you explain this reply from b&g then.

Hi Robert,*


Assuming you are planning to use a 608 mast head unit the depth and wind calibration is stored in the sensors so this data would appear correct.*


Boat speed calibration is slightly different in that the calibration value is transmitted system wide and the calculation to correct is locally carried out in each display. This means boat speed calibrated via Triton 2 o Zeus 2/3 will display correctly on all B&G displays but likely not come through correct on your N2k to WiFi device.*


I hope this helps,*
 
The sensor might be "smart" but it doesn't necessarily mean that the display manufacturer uses that capability.

I queried the reply and got this :

I'm afraid this is only partially true. The unit itself stores the depth calibration but not boat speed. This is something that has been discussed with Airmar and worked around within a B&G network however in the installation you are proposing it would behave as described below.*
 
If you look at the BandG website the transducers are described as smart or not. There is a clue there ;-)

So if you happen to know that b&g are telling me the wrong information thats great. But from what they are telling me the speed pgn on the network will be uncorrected.
 
I don't understand Buck Turgidson's comment that B&G describe the sensors as smart or not. This thread has concentrated on the DST800 triducer, and the B&G website only describes that as "smart". The NMEA2000 version of the DST800 is smart; the NMEA0183 version (not mentioned on the B&G website) isn't.
 
Top