JPI EDM 900 log accuracy

[The Other Red Baron]

I pulled the logs for the first time on the 900 and it counted 91 total flights.  I thought that sounded about right until I started looking at the data.  It turns out it has been what appears arbitrarily chopping up real flights into separate ones as far as their data is concerned. It looks like only a handful of "real" flights translate into 1 flight in the JPI data.  Does anyone know the logic behind this? I'm viewing the data using JPI's eztrends2 program.

[carusoam]

Post a link to your data and we will see what you are describing...

For the most part... each time the JPI gets powered up... it starts a new file.

Most new files start with a date and time for its name....

If you are sitting in the hangar working with your avionics... you might gather a few different flights...

 

JPIs are pretty much the opposite of artificial intelligence...    They are good devices... just not very magical.

Best regards,

-a-

[The Other Red Baron]

Yeah I get that turning the master on/off may count for 1 "flight" even if it has 0 tach or .1 tach or something, but I'm looking at my partner's most recent flight for example...

Only one person flew 1 time on 6/24.  He flew for 1.3 on the hobbs.  I don't know the gentleman that well but I'm about 99.9999% sure he didn't turn the plane off and on a couple times during the flight.   

edit: now I'm wondering if there is a certain rpm it stops adding data to the same "flight."

Edited July 1, 2020 by The Other Red Baron
edit

[ArtVandelay]

Depending on your sampling interval you may have exceeded its internal buffer limit. If I set the interval to 1 second I only get about 24 hours of logging before it starts to overwrite it’s logs. Other wierd things happen, so I set it to 2 seconds.

[carusoam]

Try to post your data into savvy...

I bet we see some interesting voltage readings...

It looks like the JPI thinks it is getting turned on and off along the way...

You might have a loose wire... I’m not sure what we will see in the data...

Has anyone seen the JPI go off on its own?

Best regards,

-a-

[ArtVandelay]

Yeah I get that turning the master on/off may count for 1 "flight" even if it has 0 tach or .1 tach or something, but I'm looking at my partner's most recent flight for example...

Only one person flew 1 time on 6/24.  He flew for 1.3 on the hobbs.  I don't know the gentleman that well but I'm about 99.9999% sure he didn't turn the plane off and on a couple times during the flight.   
edit: now I'm wondering if there is a certain rpm it stops adding data to the same "flight."

Yes there is, sometimes a runup shows up as a separate flight, if doing stalls it might think that pulling engine to idle is the end of the flight.

[ArtVandelay]

Try to post your data into savvy...
I bet we see some interesting voltage readings...
It looks like the JPI thinks it is getting turned on and off along the way...
You might have a loose wire... I’m not sure what we will see in the data...
Has anyone seen the JPI go off on its own?
Best regards,
-a-

I believe savvy will ignore the short flights, or at least that’s an option.

[The Other Red Baron]

28 minutes ago, ArtVandelay said:

Yes there is, sometimes a runup shows up as a separate flight, if doing stalls it might think that pulling engine to idle is the end of the flight.

I think that is exactly what is happening.  I found the simulator option on eztrends2 and watch the rpm during his run-up and during the idle check it cuts off around 300-ish.  I don't know if it explains all of these though but I don't have intimate knowledge of every time the engine dipped below ~300rpm.

 

edit: made a savvy account and uploaded the JPI file.  Not sure how to make data public yet.

edit2: not really liking how Savvy does its shared links and makes it look like you are logged in as that person.

Edited July 1, 2020 by The Other Red Baron
edit

[carusoam]

Now that we have more details... let’s ask @Jeev..?

What causes the JPI to start a new flight of data, during an actual single flight..?

 

Jeev owns an avionics shop and is pretty handy with the JPI line of products...

 

Bingo... data at savvy seems to be missing all the fractional stuff...

Now for the next question... why bring the rpm back sooo much... mine is part of the Engine idle set-up... rpm doesn’t go below 600 rpm or so at any time...
 

Best regards,

-a-

[ArtVandelay]

Select the option to hide short flights, in lower right corner.

[The Other Red Baron]

Just now, ArtVandelay said:

Select the option to high short flights, in lower right corner.

Yup that helps a bit but some are still chopped up.  I guess I expected 1 flight to be start up to shut down.

[The Other Red Baron]

Alright, I probably should have RTFM again before starting a thread but I'm guessing they say data logging starts at 500RPM.

[carusoam]

Select any file and have it show rpm or any other variable of interest...

This one is the first flight on the list...

And it ends... see the rpm value... the one after that may be the limit...

Best regards,

-a-

[ArtVandelay]

Yup that helps a bit but some are still chopped up.  I guess I expected 1 flight to be start up to shut down.

I can solve your problem, connect the JPI to your GPS, then it won’t have to guess using RPMs, I think it uses GPS speed to figure out flights begin and end.

[The Other Red Baron]

2 minutes ago, ArtVandelay said:

I can solve your problem, connect the JPI to your GPS, then it won’t have to guess using RPMs, I think it uses GPS speed to figure out flights begin and end.

Now you've given me more to investigate.  We had no idea about all these small options during install time and were too dumb to check/ask and no one mentioned them.

Edited July 1, 2020 by The Other Red Baron

[carusoam]

Grab the book... do some reading...

Most people are not aware of any of the options... including time between data points...

So much data can be gotten out of the run-up... yet people miss this because they do a run-up old school style... and have the data rate set like they are running out of megabytes....

There is a ton of data in there... you need it when things don’t work right...  that is a crummy time to have to grab the book and start reading...
 

-a-

[Oldguy]

Maybe it's just me, but I am really impressed you can pull your rpm back to around 300.

[The Other Red Baron]

25 minutes ago, Oldguy said:

Maybe it's just me, but I am really impressed you can pull your rpm back to around 300.

My CFII and I are as well.  I don't think it idled quite that low before annual.  It is kind of an unnerving sound being that low rpm but it'll keep running.

[Marauder]

And you get to plot your flights with the GPS connected.

[Oscar Avalle]

Just download the data after each flight.


Sent from my iPhone using Tapatalk Pro

[Jeev]

On 6/30/2020 at 9:26 PM, carusoam said:

Now that we have more details... let’s ask @Jeev..?

What causes the JPI to start a new flight of data, during an actual single flight..?

 

Jeev owns an avionics shop and is pretty handy with the JPI line of products...

 

Bingo... data at savvy seems to be missing all the fractional stuff...

Now for the next question... why bring the rpm back sooo much... mine is part of the Engine idle set-up... rpm doesn’t go below 600 rpm or so at any time...
 

Best regards,

-a-

Looks like the sharp Mooneyspacers figured this one out!  I have not been here in a few weeks due to work and flying schedules, miss you all