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cryptik · 13-09-2018, 15:03

Got hopefully an easy question. I know I can have OCPN output a message using the PushNMEABuffer() method. I have OCPN configured with one COM port setup to receive strings from a class A AIS. So, it is setup as "input". I then have a plugin that receives strings from the AIS by monitoring the SendNMEAMessage(). This all works just fine. What I want to do now is to send NMEA strings to the AIS that include configuration commands. I have the code doing that..but when I call the PushNMEABuffer() method, I see the strings appear in the OCPN NMA debug window as (Virtual

while the strings coming in say (Serial:COM1). I assume that if the port in the configuration settings is only configured as "input" then the PushNMEABuffer() does not actually send anything (i.e. "virtual"). So, if I configure the port as "input/output" by checking the "output on this port (as autopilot or NMEA repeater)", will OCPN repeat the incoming commands from the AIS as output? Is there a way to configure the settings so the only strings going out are the ones sent via the PushNMEABuffer() method?

- thx
Ken

seandepagnier · 13-09-2018, 16:20

I believe it will output on the port if the plugin pushes it but I never actually tried this case.

As for the only strings going out.. you could set a filter in the connection to only pass those messages, but I don't think there is a way to prevent them from being sent if the same messages arrived from a different connection rather than your plugin.

cryptik · 13-09-2018, 16:44

Quote:

Originally Posted by boat_alexandra

I believe it will output on the port if the plugin pushes it but I never actually tried this case.

As for the only strings going out.. you could set a filter in the connection to only pass those messages, but I don't think there is a way to prevent them from being sent if the same messages arrived from a different connection rather than your plugin.

All good info. I did some testing and it does send out the message once you setup the port as a repeater. The down side is that it repeats all incoming messages. Your filter idea is a good one. Enabling the outgoing filter does block sentences from being repeated but you can only select from a subset of messages. My AIS sends out a couple of strings that OCPN does not include in the filter list (i.e. GPGSA) BUT, adding an input "accept only" rule and a "drop" rule on output got me to where I needed to be. Thanks for the tip.

nohal · 13-09-2018, 19:04

Quote:

Originally Posted by cryptik

All good info. I did some testing and it does send out the message once you setup the port as a repeater. The down side is that it repeats all incoming messages. Your filter idea is a good one. Enabling the outgoing filter does block sentences from being repeated but you can only select from a subset of messages. My AIS sends out a couple of strings that OCPN does not include in the filter list (i.e. GPGSA) BUT, adding an input "accept only" rule and a "drop" rule on output got me to where I needed to be. Thanks for the tip.

You can add absolutely anything to the filter (Click on the "Add" button), the predefined list is there just to save you some typing for the most common message types...

cryptik · 13-09-2018, 21:50

Quote:

Originally Posted by nohal

You can add absolutely anything to the filter (Click on the "Add" button), the predefined list is there just to save you some typing for the most common message types...

LOL, I did not even see the add button and it's right there. Thanks for the tip, that solved my issue and made my day

cryptik · 14-09-2018, 08:48

So with the OCPN filters, I am able to receive sentences from my pilot port connected AIS and I can send out command messages to the AIS over the same port. Basically, I have no filters on the input and I have an output filter that only transmits ECBBM messages to the AIS. When running, I can see my ECBBM messages going out and the output filter blocks the retransmission of input strings from the AIS.

But, I have a new issue. It appears that everything sent out using PushNMEABuffer() is also passed to SendNMEAMessage() and comes back to my plugin. Setting an input filter on the port does not have any effect since this incoming message is being send by OCPN and not really coming in on the port.

Is there a way to suppress this? If not, I guess I could just add code to my SendNMEAMessage() method that ignores ECBBM messages (which are assumed to be coming from OCPN rather than the AIS).

- thx
Ken

cryptik · 14-09-2018, 08:52

Okay, ignore that last post. I can see why OCPN has to function that way. Sending a sentence from a plugin may need to be received and handled by another plugin, so it has to be broadcast. I gather the correct design assumes that each plug only processes the messages they are interested in and should then ignore all other messages in the SetNMEASentence() function.

nohal · 14-09-2018, 10:06

There is no setting to exclude your messages from what gets retransmitted to all the plugins - it's their responsibility to process only the messages they are interested in. In your case, simply ignore your own messages coming back.

cryptik · 08-11-2018, 15:27

Got a quick question. In most of the example plugins that I have looked at, the windows descend from wxDialog. Is it possible to use wxFrame for the main plugin window instead?

The reason I want to use wxFrame is that I need to have a wxWidgets status bar and I cant put a status bar on a wxDialog… at least not with wxFormBuilder.

- thx
ken

nohal · 08-11-2018, 20:11

Quote:

Originally Posted by cryptik

Got a quick question. In most of the example plugins that I have looked at, the windows descend from wxDialog. Is it possible to use wxFrame for the main plugin window instead?

The reason I want to use wxFrame is that I need to have a wxWidgets status bar and I cant put a status bar on a wxDialog… at least not with wxFormBuilder.

- thx
ken

yes, it is.

cryptik · 23-01-2019, 19:01

I have an OpenCPN plugin that I use to control a depth sounder that accepts proprietary NMEA-like strings. I need to configure the OCPN comms module to send out commands... which I have working... using PushNMEABuffer(). My use case requires that I turn on the transmit filters to limit output to just the proprietary command strings (so as to limit rebroadcast other standard NMEA strings). My problem is that the talker ID for the proprietary command strings that I have to support is 4 characters long. I need to modify the transmit filters to allow 4 character filters. The filters currently only support 2, 3, and 5 character lengths. Does anybody know if its feasible (via a simple code fix) to enable this in the filter code in the OCPN base? Any pointers on where to start looking?

Thx,
Ken

nohal · 23-01-2019, 19:36

https://github.com/OpenCPN/OpenCPN/b...ions.cpp#L9443 and https://github.com/OpenCPN/OpenCPN/b....cpp#L727-L741

Haven't seen this code for a long time so maybe I forgot some other place... Looking forward for a PR implementing this custom format.

cryptik · 23-01-2019, 20:14

Perfect, thanks Nohal. I also have a plugin that sends/receives binary broadcast messages to an AIS that I would like to package and add to the repository. However, I assume there is not a lot of demand for it since I don't think class B AISs support BBMs and I am not sure how many OCPN users are using class As... although, the price is coming down on these radios considerably. I will probably need some pointers, at some point, on how to submit a plugin and/or a PR. I have not done that sort of thing before with git. I am somewhat still old school with SVN...lol

bcn · 24-01-2019, 01:33

Quote:

Originally Posted by cryptik

Perfect, thanks Nohal. I also have a plugin that sends/receives binary broadcast messages to an AIS that I would like to package and add to the repository. However, I assume there is not a lot of demand for it since I don't think class B AISs support BBMs and I am not sure how many OCPN users are using class As... although, the price is coming down on these radios considerably. I will probably need some pointers, at some point, on how to submit a plugin and/or a PR. I have not done that sort of thing before with git. I am somewhat still old school with SVN...lol

What might be handy is an interface to edit the voyage related data of the Class A AIS from OpenCPN.