Webb

Webb

Well Known Member
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Can you run the R232 line from your GPS into both the autopilot and the engine monitor at the same time? Or is the signal attenuated such that it won't work for both units.

Autopilot (Digitrak) is manditory, Dynon EMS is optional and I don't have a glass panel.

Only reason for asking is fuel calculations.

Now's the time to cut long and store, or crimp and attach.
 
Crimp and attach. Common practice to tie 2 or 3 devices (receive lines) on the same transmit line. As long as everything speaks the same protocol and baud rate, your golden.
 
I've done this from my Garmin 396 to the following devices:
1. Dynon D10A
2. JPI FS-450 Fuel Flow
3. TruTrak Pictoral Pilot

Works great. I haven't had any problems with any of these reading from the same signal wire. Someone else may come along and tell me that I'm crazy for doing it this way, but I figure that since the garmin is the only one writing signal on the wire and the other 3 do only reads, it shouldn't matter much.
 
Speak same

Brantel said:
Crimp and attach. Common practice to tie 2 or 3 devices (receive lines) on the same transmit line. As long as everything speaks the same protocol and baud rate, your golden.
Click to expand...

Ok - Garmin 430, Digitrak II, and Dynon EMS. Golden??
 
things that make you go hmmmmm......

Brantel said:
You should be in great shape. Check the manuals to be absolutely sure.
Click to expand...

Somthing tells me that this is one of those.......you know it's OK but hold your breath when you turn it on.......grit your teeth...and hope for no smoke....

Based on the fact that the R232 is an output line and the AP and EMS are just receiving input, it shouldn't be an issue. Worse case.....430 output too low and I cut the EMS lead. I don't think that is going to happen since the leads are so short anyway.....

As always, I'll report back later when I get the guts to flip the switch.......
 
Check the manual

Webb,
I agree all the 232 lines can be connected together and work, with notes from others, but....
I have the dynon D10A not the EMS so this may not apply.
Dynon updates the D10A vis the RS232 input line and it is required to disconnect the RS232 line from everything else while updating.
So read the manual as it pertains to updating and the associated wiring before you jump into a final configuration.
Hope it helps.
 
Webb said:
Something tells me that this is one of those.......you know it's OK but hold your breath when you turn it on.......grit your teeth...and hope for no smoke....
Click to expand...


There's no worries about smoke Webb - it's common and accepted practice to split the serial line to multiple devices. the reason people say to "check the manuals" is for the protocols - the signal LEVEL will be just fine, but you'll need to make sure that all the devices have a common language that they will understand. Most common GPS's put out NMEA183, so MOST devices understand that. But some companies think they're special and will only understand their own proprietary code. So you'll have to open up all the manuals and compare data format tables to find what is common.

Paul
 
Bob Martin said:
Webb,
I agree all the 232 lines can be connected together and work, with notes from others, but....
I have the dynon D10A not the EMS so this may not apply.
Dynon updates the D10A vis the RS232 input line and it is required to disconnect the RS232 line from everything else while updating.
So read the manual as it pertains to updating and the associated wiring before you jump into a final configuration.
Hope it helps.
Click to expand...

According to Dynon, if you only have an EMS-D10 without magnetic heading from an EFIS, the HSI page will not be functional. You should connect a the R232 transmit line connection from the GPS to pin 19 on the Dynon. It will give you on fuel endurance info (range, MPG, etc..) on the fuel page and GPS info (track, ground spreed, course, etc..) on the HSI page. There is no need to break the connection when doing PC updates. You just hook up the serial port to the EMS-D10 and away you go. I'm hopeful that I won't have to do updates, however the thought of having programed checklists is preferable.
 
Will check out the code

Ironflight said:
There's no worries about smoke Webb - it's common and accepted practice to split the serial line to multiple devices. the reason people say to "check the manuals" is for the protocols - the signal LEVEL will be just fine, but you'll need to make sure that all the devices have a common language that they will understand. Most common GPS's put out NMEA183, so MOST devices understand that. But some companies think they're special and will only understand their own proprietary code. So you'll have to open up all the manuals and compare data format tables to find what is common.

Paul
Click to expand...

Like the "secret" handshake - I'll check out the code to make sure that everything shakes hands. I'm probably good to go.

The "smoke" was one of those expressions. I'm not really worried about that, just expressing the proverbial "keeping my fingers crossed".
 
More along this line (pun intended)

I am hooking up my fuelscan FC-10 and have the same concerns about doubling up the wires.

I understand the output of one device being able to talk to two or more listening devices, but, what about a single device like my 430 hearing a signal from both the 327 transponder and the fuelscan on the same wire?

I am adding th4e FC-10 to an already functioning installation. I am pretty sure that the 430 and the 327 are talking back and forth on rs232 lines 56 and 57. The FC-10 wants to use the same two lines if I read the instructions correctly. It doesn't seem to me like this is going to work?

Also, anyone know off hand what else I should do while I'm in there to prepare for a 496 in my future? I will end up with a GNS 430, 327 transponder and a 396 or 496 (as well as the FC-10 fuel scan computer).

Thanks,

Help---
 
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Sorry Jim - as you suspect, one box can't listen to two different boxes at the same time on a single 232 line - it would hear nothing but gibberish. You could put in an input switch if you wanted to listen to one or the other at different times - I have this on my autopilot input - I can run it off of the EFIS feed, or directly from the 430 if the EFIS dies. (I test the 430 position about once a year....)

Paul
 
Actually, serial ports as we know them on our avionics equipment are a three wire subset of the old 25 pin RS232 computer standard. The three pins are transmit (TX), receive (RX) and ground. Thus, a generic serial port can send or receive data at the same time on these 3 pins.

Data is transmitted or received in a serial or bit at a time fashion with start, stop, and parity bits to frame each byte. The baud rate of a port is the bits per second that are sent between ports and is normally set as part of the device configuration process. Obviously, communicating ports must use the same baud rate (and the same data protocol as noted in an earlier posting).

So each port at a device (eg, GPS) normally has these 3 pins for each port on the device although some devices have only transmit or only receive functions and associated pins. A TX pin can drive multiple RX pins on other devices, but multiple TX pins cannot be connected without corrupting the data transfers.

So, knowing the above, one can configure their system. Use a TX line on a device to send data to other devices that can take the data on their RX lines. An example would be an EFIS sending altitude data to a transponder to use for altitude encoding (Mode C). And as noted above, multiple RX devices can be connect to a single TX line such as in the case of a GPS sending positon data (TX) to both an EFIS (RX) for map operation and to a autopilot (RX) for course naviagtion.

Interestingly, a device such as an EFIS could send altitude data to the transponder on the TX side of one port, it could also receive GPS position data on the RX line of the same port if the device allows it. So one must consider both the TX and RX side of each port and the baud rate and protocols required by each port.
 
Jimd said:
I am hooking up my fuelscan FC-10 and have the same concerns about doubling up the wires.

I understand the output of one device being able to talk to two or more listening devices, but, what about a single device like my 430 hearing a signal from both the 327 transponder and the fuelscan on the same wire?

I am adding th4e FC-10 to an already functioning installation. I am pretty sure that the 430 and the 327 are talking back and forth on rs232 lines 56 and 57. The FC-10 wants to use the same two lines if I read the instructions correctly. It doesn't seem to me like this is going to work?

Also, anyone know off hand what else I should do while I'm in there to prepare for a 496 in my future? I will end up with a GNS 430, 327 transponder and a 396 or 496 (as well as the FC-10 fuel scan computer).

Thanks,

Help---
Click to expand...
See this thread: http://www.vansairforce.com/community/showthread.php?t=15795&page=2

which includes this diagram. The good news is that the Garmin 430 has multiple serial ports.
430wiring.jpg
 
That All Helps-

I found the diagram and that helps, although I would not have thought you could send and recieve from the fuel computer on two different rs323 ports (in on 1 and out on two or the other way round.)

Bottom line, I should be able to make this work using the diagram above method.

Thanks!

Jim
 
Quick FYI for others reading this thread...be a little bit careful.

Indeed the GNS-430 has multiple serial outputs, but only ONE at a time can be configured for aviation. The previous diagrams are great, but sometimes people think that because there are multiple RS-232 ports that you can have all of them do the Aviation out....in fact you can use any of the ports, but only ONE of them can be assigned to Aviation data. Why, I don't know - we need to yell at some engineer! :)

Cheers,
Stein
 
Dynon D-10A serial bus connections

One of the ways to avoid the issue of isolating the Dynon RS-232 bus for software updates is to use a "center off" toggle switch for the connections to the serial ports from the GPS and Garmin AT SL-30. The photo below is of the switch on my panel.

DSCS0121.JPG


The UP position connects my GPS 296 RS-232 port to the Dynon input port. The DOWN position connects the data from the VOR/Localizer portion of the Garmin AT SL-30. The CENTER position isolates the Dynon serial port from all sources except for the original DB-9 connector of the SteinAir wiring harness that came with the Dynon unit when I ordered it from SafeAir.

When I hook up that DB-9 connector to my laptop, the switch is in the CENTER OFF position, insuring Dynon is the only unit talking to the computer.
 
Each Dynon unit their own Serial plug?

I am wiring my Dynon EFIS, HS34 and EMS. Does each unit need their own serial plug for updating via a computer, or will they share the data via the DSAB-connections?

Regards, Tonny.
 
Each one its own!

I spoke to Dynon Support and they were very clear:
Each unit needs to be programmed/updated separately.
There is two ways of doing this: have a D-sub receptacle for each unit (3 in my case) or use a switch to switch the unit, that you are updating, to a single D-sub receptacle.

Regards, Tonny.
 
Porcine Smart Coupler

As I understand it, the Century autopilots are Analog (Synchro A B C) autopilots. You will need a converter such as the Porcine Smart Coupler to convert the digital NMEA from the 496 to analog commands that the Century will understand. The Porcine adapter converts the digital NMEA signal and then mimics the output from an autopilot DG to feed the autpoilot.

sc2.jpg
 
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