GPS install?

[Ron_B]

As per your manual it says " strongly reccomended to connect the GPS data line to both Skyview displays for redundancy ". Do I connect both the RX and TX? Should I connect the power and ground from both displays also?
A better description for us non avionics guys would be appreciated.
Thanks Ron

 

[dynonsupport]

Yes and Yes. Thanks for the feedback.

 

[Ron_B]

I'm still confused. Is the installation guide, revision B incorrect also (revision A), as this is the second time Dynon support has indicated that both TX and RX on the SV-GPS-250 connect to both displays. Yesterday by phone I was told this and told to get revision B ( first I heard of revision B and I'm on here every day). And the above post says connect all Tx and Rx to both displays.
Version B page 7-3 says to connect the SV-GPS-250's to the power, ground and TX line. And to connect the GPS's RX line to only one display. The guide makes more sense to me?
Ron

 

[dynonsupport]

Sorry, I goofed. The rule with serial devices is that a single transmitter can be received by multiple devices, but a receiver can only be spoken to by one transmitter (otherwise collisions occur, and RS232 serial doesn't handle collisions). So yes, the diagram is right. Technially this means that only one screen can talk to the puck, but currently this isn't done at all. That connection is basically made in case we ever need to update the firmware or change a setting in the puck some day. Then, the screen that can tx to it would talk to it. You DO want power and the tx from the GPS going to both screens so that if either fails, the other is still powering it and receiving data from it.

 

[n223rv]

So how will the dual systems operate then? I thought the master display would be the only system transmitting data, and the slave would not transmit data. Then if the master fails, the slave would become master and start transmitting data. Kinda like the backup ADHARS. It sits there until the main fails then it kicks in....

Maybe that is not possible.... But I had planned on wiring both displays serial port wires together (serial 1 tx together, serial 1 rx together, etc) then connecting the avionics accordingly.... Are we saying I can only do that on the rx side??

Thanks

 

[dynonsupport]

TX to the GPS is not nominally used. It would only be used to update the GPS or some other very infrequent operation. In fact, in today's firmware, SkyView only ever listens to the puck (ie, we haven't needed a reason to talk to it yet). So having it connected to just one screen is acceptable. There's not routine bidirectional comm there like the ADAHRS has.

 

[dynonsupport]

One additional note - the new version of the installation manual explicitly calls for the GPS rx line to be connected to just one screen.

 

[n223rv]

So what about other devices, like the SL30? With two displays, and when full functionallity is available, would we hook both the SkyView TX wires to the RX on the SL30? If so, then only one SkyView would Be able to TX at a time or there would be this collision. My thought would be that only the master screen (or only 1 screen) would TX, and if that screen failed then the other screen would TX.

If we can only wire the SL30 to one screen's TX line, then if that screen failed we would lose functionallity on the TX side.... Thoughts?

 

[dynonsupport]

So what about other devices, like the SL30?  With two displays, and when full functionallity is available, would we hook both the SkyView TX wires to the RX on the SL30?

At first just one screen's TX would be connected, and conceivably one day you could have both hooked up, with SkyView containing the capability to only TX from one screen at a time. Note that TXing to devices at all isn't supported in version 2.0, by the way, so in the case of the SL30 you'd use its OBS button/knobs to turn the course. So this theoretical capability to hook up TX lines from both screens is a ways out.

So for now, if you're hooking something up for the shorter term future (where just one screen can TX), just hook up one screen's TX wire to the SL30. Again, note that it won't be utilized in 2.0.

 

[stede52]

I've looked at all the posts on the GPS-250 install and as usaual I think I'm still confused. I have two 10" SV's and set up the 250 per the latest instructions and diagrams (Ver. B, pg 7-3 fig. 45) . I attached the RX line from the 250 to only one panel and configured each panel to POS 1, etc. I still can't get the map or synthetic vision on the panel which the RX is not connected to. When I connect the 250 RX line to both panels I get the Map and SV on each. What am I doing wrong :-/? It's probably simple, I just can't see it :-[
Based on my understanding of what was said by Dynon support in this post is that they change there minds about connecting the RX to both panel and stated the diagram is correct after all :-?

Steve

 

[thibault]

Steve,

Be sure you are always using the latest Installation Manual. The latest is Rev C. since Firmware 2.0 came out in May. In this case both manuals read the same and you are right that they do say different things on the same page for this topic.

Logic brings us the right answer however. Most GPSs can deliver data to many users but take instructions from only one supplier. The GPS TX line supplies the data and many users can be connected to that line at the same time. To give instructions to the GPS it is important that only one device can do that at a time, so only connect one to the GPS RX line. These are the words in the paragraph on pg 7-3. The drawing has the name of the TX and RX lines reversed at the screens. So re-label those two connections in the drawing. The 2nd line of each screen connection in Fig 45 should be Serial Port n RX. The 3rd line for the lower screen should be Serial Port n TX The actual wires for these depend on which Serial Port you use. If you are using Serial Port #5 for the GPS 250 connection, the Serial Port RX line of each screen connection in Fig 45 becomes DB-37 Pin 11. These can literally be soldered or butt connected together with the GPS TX line from the GPS 250. On one of the screens, connect the GPS 250 RX line to DB-37 pin 12. On the other screen, connect nothing to pin 12. Connect the ground and power lines from the GPS 250 to both screens through DB-37 Pins 24 and 29, respectively.

I think you discovered this yourself, just didn't believe it. Bottom line is if you intended to use Serial Port 5 on both screens for GPS 250 and had gray-violet to gray-violet to gray-violet on both screens and one screen had gray-orange to gray-orange plus you had the powers and grounds all connected, then it should have worked and that is what the manual was trying to say.

Good luck.

Tom

 

[stede52]

Tom, your right, I did come to the same conclusion but only by dumb luck, however, I do have to disconnect one of my screen Gray&Orange lines. It all makes sense now but since I'm not confortable with electrical I really don't see the logic sometimes. Your explanation was excellent thanks so much.

Steve