Autopilot Support

[Neptune's Gear]

Hi, Sorry if this has been asked before, but I can't find an answer. I have a simrad AP, it requires the NMEA sentence APB. Anyone got one of these to work with opencpn?

[George64]

I have the same AP and would also like to have some extra nmea sentences send to the AP. i read that the development team is looking/working n a more extensive nmea configuration.

[Neptune's Gear]

Hi George, thanks for your reply. Could you point me at that info so I can follow what's happening?
Thx

[George64]

Have a look at the development topics regarding the latest opencpn versions.

[Neptune's Gear]

OK, looking into this a bit closer. AP works fine in Nobeltec, APB, RMB,RMC;

$ECAPB,A,A,0.001,R,N,V,V,256.8,M,017,256.9,M,256.9 ,M*3A
$ECRMB,A,0.001,R,-Activat,017,2216.640,S,16625.977,E,0.41,269.2,-0.00,V*7F
$ECRMC,111624,A,2216.634,S,16626.415,E,0.00,135.6, 191012,12.30,E*43

Does not work in Open CPN;

$ECRMC,111957,A,2216.633,S,16626.414,E,0.000,0.000 ,191012,,,*38
$ECRMB,A,29.004,L,017,018,2154.038,S,16645.944,E,2 8.912,38.690,0.000,V*3E

So there is something in APB that makes the diff. Not Dev, that is present in RMC, both systems. So it should not be M or True issues. The formats for the sentences are here;

RMC Recommended Minimum Navigation Information

1 2 3 4 5 6 7 8 9 10 11|12
| | | | | | | | | | | |
$--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx, x.x,a*hh
1) Time (UTC)
2) Status, V = Navigation receiver warning
3) Latitude
4) N or S
5) Longitude
6) E or W
7) Speed over ground, knots
8) Track made good, degrees true
9) Date, ddmmyy
10) Magnetic Variation, degrees
11) E or W
12) Checksum
RMB Recommended Minimum Navigation Information

1 2 3 4 5 6 7 8 9 10 11 12 13|14
| | | | | | | | | | | | | |
$--RMB,A,x.x,a,c--c,c--c,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,A*hh
1) Status, V = Navigation receiver warning
2) Cross Track error - nautical miles
3) Direction to Steer, Left or Right
4) TO Waypoint ID
5) FROM Waypoint ID
6) Destination Waypoint Latitude
7) N or S
8) Destination Waypoint Longitude
9) E or W
10) Range to destination in nautical miles
11) Bearing to destination in degrees True
12) Destination closing velocity in knots
13) Arrival Status, A = Arrival Circle Entered
14) Checksum

APB Autopilot Sentence "B"

1 2 3 4 5 6 7 8 9 10 11 12|1314|15
| | | | | | | | | | | | | | |
$--APB,A,A,x.x,a,N,A,A,x.x,a,c--c,x.x,a,x.x,a*hh
1) Status
V = LORAN-C Blink or SNR warning
A = general warning flag or other navigation systems when a reliable
fix is not available
2) Status
V = Loran-C Cycle Lock warning flag
A = OK or not used
3) Cross Track Error Magnitude
4) Direction to steer, L or R
5) Cross Track Units, N = Nautical Miles
6) Status
A = Arrival Circle Entered
7) Status
A = Perpendicular passed at waypoint
8) Bearing origin to destination
9) M = Magnetic, T = True
10) Destination Waypoint ID
11) Bearing, present position to Destination
12) M = Magnetic, T = True
13) Heading to steer to destination waypoint
14) M = Magnetic, T = True
15 is checksum.
I need to get this working before open CPN is a workable alternative to Nobeltec. Can anyone help? How hard is it to ad the APB sentence?

Thanks

[Neptune's Gear]

Bump.Still a problem...

[Tugwit]

I seem to have a similar issue. I am using OpenCPN 3.2.0 and cannot get my new Simrad TP32 autopilot to recognize and follow a route set up in OpenCPN. The TP32 consistently refuses to enter "NAV" mode to follow the compass headings specified by the route.

Oddly, I also use PolarView/PolarCOM and the TP32 does recognize the route, happily enters "NAV" mode, and follows it!

Both EC programs are configured to output ECRMB and ECAPB and I have verified that the sentences appear at the autopilot 0183 input. The only significant difference I see in the content of the sentences produced is that bearings in PolarCOM are output as MAGNETIC, while bearings in OpenCPN are output as TRUE.

Has anyone had success using OpenCPN with a Simrad TP32 pilot?

[George64]

I do have it working, same config only newer O version. Did you check the tp32 manual for the required sentences? I'm not sure if ecrmb contains all wp-info.

(Two wires can cause a lot of headache)

[Tugwit]

Hi George. Appreciate your reply! Are you using O 3.2.2?

Yes, I have examined the TP32 manual and it is not very explicit as to the precise requirements. It says ...

"...NMEA0183 required for full functionality of the TP22 and TP32 whilst in NAV mode is as follows:
-Cross Track Error
-Bearing to Destination Waypoint
-Arrival at Waypoint Indication
-Magnetic Variation
-Boat Speed

It goes on to say "...this information is extracted from the following NMEA0183 sentences...APA, APB, RMA, RMB, RMC, BWR, BWC, BWW, VHW, XTE"... without offering any further clarification or suggestion.

Now, APA is an obsolete 0183 sentence, having been replaced by APB. Similarly RMA--which uses Time Differences rather than Lat/Lon.

Bottom line: while I have primarily a NMEA2000 system, I could not get the TP32 to work (enter NAV mode) with data supplied solely on the N2K bus--even though OpenCPN (and PolarCOM) both generate 0183 sentences which are translated to PGN 129283-XTE and 129284-Nav Data which appear on the N2K net. (the TP32 does, however, steer to Wind using N2K data only!)

As a result, I connected the optional TP32 NMEA0183 wires to the NMEA 0183 side of my system (NGW-1-ISO feeding an Em-trak B100 AIS serving as a bi-directional MUX and into the PC which hosts the EC software. Output from the PC (RMB, APB) "talks" to both the AP and the NGW; the NGW, in turn, translates the RMB and APG into the N2K PGN above. )

With this configuration I see representative PolarCOM output as:

$ECRMB,A,0.00,L,RT002,,4703.5670,N,12253.8051,W,0. 27,358,0.21,V*18
$ECAPB,A,A,0.00,R,N,V,V,342,M,RT002,342,M,342,M*1B

while OpenCPN output is:

$ECRMB,A,0.000,R,001,Swanto,4703.566,N,12253.805,W ,0.258,358.532,0.000,V*10
$ECAPB,A,A,0.000,R,N,V,V,358.498,T,Swanto,358.525, T,358.525,T*26

Initially, I configured OpenCPN to transmit all remotely relevant 0183 sentences to the TP32. No Joy.

Monitoring the PolarCOM output which only produces RMB and APB, I restricted OpenCPN output to only the two sentences ECRMB and ECAPB so that input to the TP32 would be identical (except for content of the sentences). Any other data needed by the TP32 is presumably supplied by N2K PGN (e.g. magnetic variation).

By counting the fields in the formatted RMB and APB sentences above, you see that the format of the sentences (i.e. number and position of fields) is the same. However, bearings in PolarCOM are MAG, while bearings in OpenCPN are, of course, TRUE. This is the only difference I see in the 0183 data supplied to the autopilot. Yet PolarCOM works (i.e. enables the TP to enter NAV mode) and OpenCPN doesn't.

I'm stumped.

How is your equipment configured? Is your TP32 connected to SimNet/N2k? What 0183 sentences are supplied to your TP32 to get it to enter NAV mode?

[George64]

Mine is connected to a nmea0183 network and using a beta version of O, one of the latest.

Out of my head, I send more nmea-sentences tot the TP32. I also think it needs RMC.

Is "swanto" the waypoint you want to steer to?

[Tugwit]

Originally Posted by George64

Mine is connected to a nmea0183 network and using a beta version of O, one of the latest.

Out of my head, I send more nmea-sentences tot the TP32. I also think it needs RMC.

Is "swanto" the waypoint you want to steer to?

Yes, "swanto" is the shortened form of "Swantown Marina Entrance", the label I used on the destination waypoint.

Interesting to note that PolarCOM omits the destination waypoint ID from its RMB while it appears (at least in shortened form) in OpenCPN.

Clearly the TP32 doesn't care that there's no destination ID.

[brianalex]

Originally Posted by NZ8720

OK, looking into this a bit closer. AP works fine in Nobeltec, APB, RMB,RMC;

$ECAPB,A,A,0.001,R,N,V,V,256.8,M,017,256.9,M,256.9 ,M*3A
$ECRMB,A,0.001,R,-Activat,017,2216.640,S,16625.977,E,0.41,269.2,-0.00,V*7F
$ECRMC,111624,A,2216.634,S,16626.415,E,0.00,135.6, 191012,12.30,E*43

Does not work in Open CPN;

$ECRMC,111957,A,2216.633,S,16626.414,E,0.000,0.000 ,191012,,,*38
$ECRMB,A,29.004,L,017,018,2154.038,S,16645.944,E,2 8.912,38.690,0.000,V*3E

So there is something in APB that makes the diff. Not Dev, that is present in RMC, both systems. So it should not be M or True issues. The formats for the sentences are here;

I struggled with this on a Raymarine autopilot. My GPS did not provide OpenCPN with magnetic variation.

If you compare the $ECRMC from Nobeltec with the $ECRMC sentence from OpenCPN you will notice the magnetic varition is missing from the OpenCPN sentence.

Adding the plugin WMM_pi inserts magnetic variation into the $ECRMC sentence. This fixed it for me. Hope it works for you.

Brian

[Tugwit]

Originally Posted by brianalex

I struggled with this on a Raymarine autopilot. My GPS did not provide OpenCPN with magnetic variation.

If you compare the $ECRMC from Nobeltec with the $ECRMC sentence from OpenCPN you will notice the magnetic varition is missing from the OpenCPN sentence.

Adding the plugin WMM_pi inserts magnetic variation into the $ECRMC sentence. This fixed it for me. Hope it works for you.

Brian

Thanks for your suggestion, Brian.

Unfortunately, the RMC supplied to my AP contains a valid magnetic variation, but the AP still refuses to follow an OCPN route.

Analyzing what works (PolarView/PolarCOM) and what doesn't (OCPN) the only difference I find is that the APB sentence produced contains all Magnetic bearings (PolarCOM) and all True bearings (OCPN). The RMB sentence produced by both products is identical (its sole bearing is constrained to be TRUE by definition of RMB).

[rgleason]

This discussion thread looks like it is making progress on Autopilot connections.
Please post any specific Autopilot Support Improvements in Tracker Opencpn Feature Requests. Register and sign in. Then Pick the Opencpn Feature Request from the upper right project dropdown. Thanks.

[Hakan]

I've a Simrad WP30 AP and it work's fine with OCPN. On the com port I use a filter like: In: None , Out: Send ECRMB,ECRMC,VWR,MWV. (The two latter for wind control) This filter prevents other RMB/RMC then the those created by OCPN to be by passed to the AP.