Joe Hull is a pretty good programmer and said he would take a look at it
but don't have any commitments at this point. Any and all help would be
appreciated on either part of this project. I'm simply out of time to do
it all myself. Any contributor will get full credit for their efforts and
if this stuff ever makes any profit, I'll count you in for royalties!
(hint, it won't be like winning the Power Ball Lotto : )
For anyone interested, Boring technical details of the task follow
below: All others may delete message now.
Data logger protocol
This protocol is still being worked out so if you have any suggestions to
make it easier of more reliable, fire away.
The first part needed is a PC Program to input a stream
of data words on a serial port from the data logger and
store them as a disk file. The words will represent multiple blocks of 28
14 bit values. Each 14 bit word in the block is one of
the 28 data channels in the EM2 engine monitor. There is one 28 word
block for each 2 second sample period. Definition and order of data words
still being developed.
The serial data file stream is preceded by a file start
marker byte of $F9. The data words are then sent as two bytes having
the msb (bit 7) cleared and the lower 7 bits holding the data. The least
significant 7 bits of the 14 bit word are sent first. At the end of each
28 word data block there will be an end of block marker of $FA.
The end of the data file will be signified by an end of file
marker byte of $FF.
The async serial data will come from the data logger at a baud-rate of
19,200. Currently there are no flow control lines (CTS / RTS) on
this serial interface but these could be added if necessary.
The second half will be an EXCEL spreadsheet that displays the data file as
28 channels in chart form with time being the X axis (2 seconds per data block)
and the value of each channel plotted on the Y axis. Don't know if
it is practical to display all 28 channels on one chart (would be nice, in
order to see unexpected correlations) or to have separate charts
for various groups.
Each channel will be associated with a different formula to convert the raw
sensor data word to human readable units (degrees F, PSI, etc.)
These formulas are already developed.
I have only a little EXCEL experience so I don't know if I'm expecting
too much from it or not. Your input welcome here.
Tracy
Tracy,
If you don't have any volunteers by now, get me the
details and I'll take a look at it.
-Tim
----- Original Message -----
Sent: Monday, April 17, 2006 10:14
AM
Subject: [FlyRotary] Re: Possible
data-logging solution?
I'll check this out but in the mean time I added a simple data
logger to the fly-by-wire board since it only required the addition of 1
inexpensive part. Data logging time is limited to 74 minutes at
a sample rate of once every 2 seconds. This should be
plenty for analyzing cooling & performance issues.
It ain't over yet since this only stores the raw sensor
data. As Rusty points out, I (or a volunteer with some
programming/EXCEL chops?) need to write the program to download the data and
an EXCEL spreadsheet to display it in a nice chart.
BTW, Congrats Buly! Now, give us more details on
that needed cooling tune-up : )
Tracy (did I mention I was looking for volunteer
programmers?)
Subject: [FlyRotary] Re: Possible data-logging solution?
Interesting
Phil. I just bought a serial data logger for my Dynon DS180 (EFIS
and EMS). I just received the Dynon, and data logger, so I
haven't had time to try anything with them, but this setup has
promise for Tracy's stuff as
well.
At the moment, the
unit only logs one of the two serial channels, but in the next
version of software, it will log both channels. It uses SD or
MMC memory cards, so you can take them home to read them. The OEM
version has this card slot available on the bottom of the board,
where the boxed version is enclosed. I'm told you can use any
branded memory, so you don't have to buy theirs. I got the 128 mb
version, since they seem to screw you on the memory cost, and I
can buy larger cards much cheaper from other
vendors.
They don't use the FAT
file system, so you need their "reader" program to read the memory card on
a PC, or you can use a laptop and download the data via
X-modem. Once I get the data, the next problem will be figuring out
what to do with it. I guess I'll be learning more about Excel than I
cared to know.
Cheers,
Rusty (one week until
my "sentence" in Cleveland starts)