Author Topic: datalog sampling frequency  (Read 2863 times)

the_grizzli

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datalog sampling frequency
« on: November 25, 2024, 10:49:27 PM »
Hello,
this is my first topic opened on this forum.
i connected my GS-911 to my BMW r1250Gs for the first time this afternoon and i recorded some data in real time.
i got four *.csv files.

To my great surprise (and to my great regret) the sampling frequency varies from 0.4 sec to 2.5 sec depending on the number of data recorded in the log in the log (according to the values ​​checked in the list : 5 data to 47 data).
i find it extremely low and almost unusable.
What do you think?
how to improve the data sampling frequency?
it would take at worst 0.2 sec, and at best 0.05 s to have a correct analysis of the data.

From searching the forum I understand that you can choose the sample rate... but where is this setting??

thanks
« Last Edit: November 25, 2024, 11:09:03 PM by the_grizzli »

the_grizzli

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Re: datalog sampling frequency
« Reply #1 on: November 26, 2024, 11:16:51 AM »
I notice too that the data recording is shifted in time. We don't have the same timeline for the rpm as for the handle or the lambda... not easy to use!!!

WayneC

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Re: datalog sampling frequency
« Reply #2 on: November 27, 2024, 01:02:43 AM »
I assume you are logging to the PC & are connected to the GS911 via USB, set the GS811 up to log to the internal SD card & see if the sample rate is improved, beyond that I would open a support ticket with Hexcode
https://www.hexgs911.com/contact-us/

the_grizzli

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Re: datalog sampling frequency
« Reply #3 on: November 28, 2024, 05:38:57 PM »
Thank you for your reply.
I understand that I have to connect to the GS-911 via wifi with the mobile application and thus trigger the recording/stopping of data?

WayneC

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Re: datalog sampling frequency
« Reply #4 on: November 29, 2024, 02:11:23 AM »
Yes you connect to the GS911 via web browser either via WiFi utility or D2D from phone & set it up to log to the internal SD card, it can log for months & will stop logging when you disconnect it, it is how I did beta testing for logging years ago, very handy for looking at start sequences & intermittent issues

On my home WiFi network my router is programmed to always give the same IP No to the GS911% a bookmark in the browser which makes it easy to connect to it

the_grizzli

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Re: datalog sampling frequency
« Reply #5 on: November 29, 2024, 10:23:41 AM »
thanks for the details.
i actually connect with my phone's app in D2D.
however, i don't think i saw an option to connect "directly" to the SD card...
did i miss something?

WayneC

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Re: datalog sampling frequency
« Reply #6 on: November 29, 2024, 10:39:14 AM »
thanks for the details.
i actually connect with my phone's app in D2D.
however, i don't think i saw an option to connect "directly" to the SD card...
did i miss something?

The setting to log to SD card is in the real time logging screen when you are setting the parameters to log

the_grizzli

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Re: datalog sampling frequency
« Reply #7 on: November 30, 2024, 11:29:28 AM »
it's ok for the acquisition via wifi on the SD card.

the frequency seems to be faster and 6 values ​​out of 9 are on the same timeline.
the offset between two values ​​is 380ms

On a graph, We can clearly see the offset of the high point of the accelerator handle, offset from the high point of rpm

WayneC

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Re: datalog sampling frequency
« Reply #8 on: November 30, 2024, 12:51:47 PM »
OK good to hear, with your original logging I am unsure how you had the GS911 connected

With a PC vIa USB data throughput on USB2 can be a limitation, you can set communication with PC to be TCP-IP to then to WiFi via home router & you may find improved logging rates. Used in workshops to have wire free diagnostics
« Last Edit: November 30, 2024, 12:54:14 PM by WayneC »

the_grizzli

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Re: datalog sampling frequency
« Reply #9 on: December 08, 2024, 01:20:00 PM »
Hi !
to control the fuel table, I therefore need to record these 6 parameters

"Engine RPM"
"Throttle Position"
"Oxygen Sensor Voltage (Bank 1, Sensor 1)"
"Lambda Sensor Output"
"Short-Term Fuel Trim (Bank 1)"
"Long-Term Fuel Trim (Bank 1)"

I connect my smartphone via wifi to my gs-911 and I record.
the recording rate and the lag between the different recordings is prohibitive... the recorded log is unusable...
how can HexInnovate improve this?

thanks

WayneC

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Re: datalog sampling frequency
« Reply #10 on: December 08, 2024, 02:07:56 PM »
Hi !
to control the fuel table, I therefore need to record these 6 parameters

"Engine RPM"
"Throttle Position"
"Oxygen Sensor Voltage (Bank 1, Sensor 1)"
"Lambda Sensor Output"
"Short-Term Fuel Trim (Bank 1)"
"Long-Term Fuel Trim (Bank 1)"

I connect my smartphone via wifi to my gs-911 and I record.
the recording rate and the lag between the different recordings is prohibitive... the recorded log is unusable...
how can HexInnovate improve this?

thanks

You did not mention whether you logged to SD card then downloaded the file after ending logging

Overall logging speed limitation is speed of CAN BUS & remember O2 sensors are the rather slow

Perhaps lodge a support ticket with Hexcode  https://www.hexgs911.com/contact-us/

the_grizzli

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Re: datalog sampling frequency
« Reply #11 on: December 08, 2024, 05:52:36 PM »

170 / 5 000
yes, yes
i was connected to the sd card, then i tried to use the downloaded csv file.
we can also see very well the timing differences between the lines..