On Sat, 29 Nov 2003 00:06:29 +0100, "Meindert Sprang"
wrote:

"Larry W4CSC" wrote in message
...
Now THAT is interesting.

If the multiplexer detects two sources sending the same statements at
the same loop time, does it alarm some software on the PC to warn you?

No it doesn't. The idea is that if you have two sources of the same type of
data, you can either kill one by the priority mechanism or you can assign
different talker ID's to be able to distinguish between them. If you set
both options, the application software could detect the dissapearence of the
first source because of the sudden change in talker ID when the priority
mechanism times out.

Sure would be a nice feature on that USB port of yours. Took me a
while to figure out that I had compass data coming from the B&G
Network Pilot, that I can't turn off without turning off all the B&G
instruments daisy-chained together on their own network, that was
conflicting with the Smart Heading Sensor of the Raymarine Seatalk
network. The stupid Raymarine RL70CRC kept jumping compass headings
back and forth until I figured out what was going on. It would be
just wonderful if I could tell the multiplexer, through its control
software from the computer, to ignore and don't retransmit any one of
the NMEA statements on port 2 or from a certain $ID designator. That
would override the stupid manufacturers' lack of control on what their
NMEA transmits into the network, whether you want them to, or not.
I've had to choose between NMEA wind, speed, depth from the B&G
networked instruments and the Raymarine Smart Heading Sensor. The
RSHS is more accurate and gives me rate-of-turn from its little
gyro-gizmo (gyros are great big whirling mechanisms, not tiny plastic
boxes)...but I can't dump the data from all the sailing instruments to
get it, so we're using the compass data from the compass on the B&G
Pilot only.

Example: attach to GPS's, one on input 1, the other on input 2. Set the
channel priority and channel numbers. When both GPS's run, only number one
will come through and you see sentences like M1GLL. when the first one dies,
after the timout, you will see the second one as M2GLL. There's one weak
spot he when the second GPS dies before the first, you will not notice it
until the first one dies too :-(

Interesting concept. That might work to my advantage if I were to put
the Raymarine RL70CRC on Channel 1 and the B&G with the conflicting
compass data on Channel 2. Sorry about the bug about the CH2 failure
mode....I'll keep my new sextant handy..(c;

Is there a mapping software for it to show which statements come from
which source addresses/ports?

I think so. One of my regular clients is using the multiplexers for software
that REQUIRES two different GPS inputs. (SOLAS requirement, I think) At the
moment they are using two multiplexers on each computer to achive this. With
the new one, they can use one multiplexer and set the talker ID on the
second GPS stream different from the first. In the software, they can also
program talker ID's to identify the different sources. I also remember
vaguely helping someone with Nobeltec software, that also allows you to
identify different sources by programming a talker ID in an .INI file.

I'll have to research The Cap'n .ini file. Thanks for the pointer.
The Cap'n has a very limited choice of controlling its output
statements. Only the autopilot statements have a control popup page.
I've reconfigured the network so that the computer only feeds the NMEA
input to the Pilot through a toggle switch, not the whole system as
much data is lost that way. Now that I have some experience with the
RL70CRC, I'm thinking of making it the "normal mode" master of the
entire network, not the multiplexer. The RL70CRC Plus has every
statement you feed through it controllable from a single page on its
menu tree. I feeding the talkers into the multiplexer, then feeding
the RL70CRC from the multiplexer's TX output (that old Noland problem)
and using the RL70CRC Plus as a filter to get the statements I want to
feed to all the listeners on the network, just because it is so
configurable. We always run the RL70, anyway. If it fails, a toggle
switch selects the multiplexer as master network feeder.....

Me thinks our network much too complex.....too many toys.

Thanks for the information. Too bad Lionheart is already using the
Noland....sorry.


Larry W4CSC

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