Datalogging

[13brv3]

Greetings,

Since it sounds like datalogging isn't a high priority for Dynon at the moment, I'd like to investigate other options for the D180 I just ordered.  

I know there's a program written by Waiter, that will capture the data that's on the serial link.  On his site, he mentions that it takes a fast CPU to capture everything.  I can assume that a reasonably modern notebook PC, would do this.  

While this is nice for times when you know you're testing something, I don't have room, or the desire to carry a notebook all the time.  Since I'd like the data to be recorded all the time, I'd like to find a solution that will work with a PDA, or other memory device.  

I have an IPAQ pocket PC, that runs at 400 mhz.  Can Waiter's program be compiled to run on a pocket PC?  Would 400 mhz be fast enough?  If not, how fast would it need to be?

In searching for datalogging recently, I found a statement that said there were other "devices" available that would record serial data to a smartcard.  I can't find this message again, and there was no detail as to where to find these devices.  I've done some searching, and have come up empty as well.  Is there a small device that would act as a dedicated serial data recorder?  

Thanks,
Rusty
 

 

[13brv3]

I've done some more searching, and found this:

http://www.microdaq.com/acumen/sdr-cf.php

I'm not completely sure that it will capture the serial data from the Dynon, mostly because I have no idea what format the serial data is in. It sounds like it can be configured for most anything though. The only certain problem is the price, which is up there. Otherwise, it looks like just the ticket.

Can anyone tell for sure if this would capture the Dynon data?

Cheers,
Rusty

 

[waiter]

It looks like the device you mentioned will do the job (Serial Recorder). It won't parse the data for you. It places the received data into a text file as its received. You could then read the file into Excel or Word. You'll need to come up with a way to provide power to the unit.

When connecting to the serial port to capture data, keep in mind that the Dynon is spitting out an 80 byte serial stream approximately 64 times a second. Thats about 5k per second, 300k per minute, 18meg per hour. The amount of data and the speed its coming out, presents a challenge to any program that wishes to receive the data.

I'm not complaining, I think its fantastic to have this data available "real time" in such a universally accepted method. Think of the possible applications that can make use of this data.

Waiters Flight Data Recorder was written in VB6 and makes use of several ActiveX controls. I don't think it could be recompiled to WindowsCE without some serious changes. A 400Mhz IPAQ or Palm should have no problem keeping up with the stream, as long as you don't get to carried away with parsing or display. The big advantage these devices have over the more conventional computers, is the writing speed to the storage device. Millisecond access times to write to a hard drive may seem fast, until your trying to perform a write operation every 15 milliseconds, then you usually cache the data until the point that you get a stack overflow (Exactly why the slower computers can't parse and display data, the parsing keeps getting interrupted until we get the "Stack Overflow".)

I may take a look at this if I get a little free time over the holidays.

Waiter

 

[khorton]

The data format shouldn't be a problem, if this unit works as described in its manual.  The D-10A and EMS-D10 data is simply text pushed out an RS-232 serial port.  The only peculiarity is that the data rate is 115,200 baud, which is unusually high.  I assume that the D180 will send a similar data stream.

If you wanted to use this to record data so that it was available for analysis if something interested happened, this unit has an "overwrite oldest" mode.  You would set it up to create a new file once the old one reached a certain size, and it would overwrite the oldest file if it ran out of room on the flash memory card.

This box should work, if it works as advertised by the vendor, and if the D180 sends a similar data stream to the D-10A and DMS-D10.

 

[chasspin(Guest)]

Below is a post I made back in April dealing with this subject. This post may give you some insight into how the data can be recorded. With the amount of data that is available from today's digital instruments and navigation systems the lack of standards on the message formats (except for NMEA data) makes data logging messy and difficult. There is a real need to have a system that can reformat the all these data streams into a single time stamped message and recorded at user selectable rate.

Another thought is the FDR output port could be coupled to a tranmitter (for example a cellphone when the FCC makes it legal to use them in the air) and downlink the data so the flight tests can be monitored from the ground (Just like they do at EAFB).


Charlie

Re: Flight, voice. (&video?) recorders for GA
Reply #1 on: Apr 26th, 2005, 7:31pm Quote
spinellic5@msn.com

Posts: 4
Flight data recorder is a great idea and would round out the Dynon product line! I have been looking into designing a small compact FDR using a compact flash as the recording media. The dynon products are perfect for such a system. Here's my thoughts.

I have been looking at a single board computer made by Persistor that has several serial ports and a compact flash card to record the data and runs on 3.5 volts. If take the data from the EFIS D-10, EMS D-10, and the standard NMEA -183 data from GPS and merge the data into a single data stream that is time stamped by the GPS and stored in a text format to the compact flash in a PC readable file. Note: The Dynon data may have to be downsampled to to a 1-10 Hz data rate since most GPS systems output at 1Hz.

Each message would then have The following data for example.

Time, Lat, Lon, Ground Speed, Course, Heading, IAS, Altitude, G forces, AOA, Roll, Pitch. Turn Rate, OAT, RPM, Fuel Flow, CHT, EGT, ManPress, Carb temp, oil temp, Fuel Press, etc.

These data then can be used to calculate other data and also feed 3rd party software to generate performance charts for the aircraft. This is a flight test engineers dream. You can create test cards fly the profiles and plot the performance data in Excel for example

I would suggest the data be stored as a loop recorder and then the user can continously store flight data and pull the data when needed and have the most current flight along with the previous flight hours depending on the size of the compact flash card used.

If the data message was 500 bytes stored at 10 Hz a 1Gb compact flash could store about 2 million messages and record for 55 hours before looping over the oldest data.

I used the D-10 in a flight test for some sensor research I am doing with the U of Wash to flight. I recorded the data from the GPS, d-10 and the sensor on a laptop in flight. The data was then comipled by hand and plotted in Excel. I also took the data and wrote an API plug-in for X-plane to read the data and replay the flight for a visual demonstration in a presentation I gave.

I would be glad to work with you guys if you are interested in creating a FDR product.

Charlie

 

[13brv3]

Wow, thanks for all the info!  

It sounds like the serial data recorder that I found would probably do the job.  Since it runs on 7-18V, it would be easy to hook 12V up to it in the plane.  It's also small, and light, and could mount right on the panel for easy access to the flash card, and record button.  I also had noticed the overwrite old data first feature, which is nice.  It looks like it just starts a new data file every time you hit the record button, which is also nice.  

The only downside is still the price, but even that is fairly reasonable, if it works as well as it should.  I've looked for other devices like this, and haven't found any so far.  Maybe when I get the D180 (not for a while), I'll talk to the Acumen folks about trying one of these.

Charlie, the project you suggest sound great.  With the current crop of digital devices in the cockpit, I would bet there's a growing market for an "experimental" FDR.    

 

[dynonsupport]

As an FYI, we expect that at launch, the D180 will have two serial ports, one for EFIS data and one for EMS data. This may change in the future as we work on software, but since the D180 will have EMS hardware and EFIS hardware, the fastest way for us to get it to market is to continune to keep the serial steams seperate.

 

[13brv3]

Thanks for mentioning that. I believe the gizmo I found only has one serial input, so I guess I'd have to pick either the EMS or EFIS. Not a tough choice, but it would be nice to have it all, especially for the cost of that gizmo.

Hmmmm,
Rusty

 

[bertrand]

Hello

For those who looks at datalogging otherway  than on a PC ,I'm pleased to inform you that I've just connected a Acumen data recorder  to the EFIS D10A . It works great . I did some VB script  in order to transfer rought data to an Excel sheet  and then plot graphics or do some calculations .

Bertrand  

 

[13brv3]

That's certainly good to know. I just recently received my D180, and also a serial recorder from these guys:

http://www.zen30649.zen.co.uk/product_antilog.html

The current version of software only records one channel at a time, but the soon to be released version of software will record from both channels at once. The OEM version (maybe the boxed version too) uses removable SD or MMC memory cards. Unfortunately, I won't be able to do anything with the unit for a couple months, though I'll certainly post an update when I try it.

Cheers,
Rusty

 

[bertrand]

Hi

That box do the job also .Anyway ,for my purpose I needed the recorder not to be accessible (for "all the time"  data logging)  and to have a record every time power is ON . The Acumem do this ...

Regards

Bertrand