Question

Dear

To receive harsh driving events when green driving source is set to accelerometer, it is obligated to have an calibrated accelerometer.

That's clear, auto calibrate is enabled in the device.

Only I find online that the events are only send, if the calibration is activated by SMS.

So when a new device is properly calibrated automatically during start up, and proper axis vectors are created, device will not send harsh events till a SMS is received to re-calibrate the device??

For me it makes sense that when the accelerometer is calibrated, no matter how it is started, it should send the events?

Thanks for your help!

Answer 1

Hello Koen,

Good day. Thank you for the query.

The answers to your questions are as follows:

1) To receive harsh driving events when green driving source is set to accelerometer, it is obligated to have an calibrated accelerometer?

Yes, in order for the device to send the correct event to the server, the calibration must be done correctly.

2) So when a new device is properly calibrated automatically during start up, and proper axis vectors are created, device will not send harsh events till a SMS is received to re-calibrate the device?

If the device has been calibrated, we can sent an SMS (auto_calibrate:get) to check if the calibration is successful. Then the correct event will be generated. Otherwise, false harsh event may be generated.

There are a few SMS commands that you can try out for calibration:

auto_calibrate:set	Yes	Request auto calibration task start
auto_calibrate:get	Yes	Request calibration info (time, ground vector, side vector)
auto_calibrate:clear	Yes	Request calibration clear from flash and stop calibration task
auto_calibrate:status	Yes	Request calibration status and calibration task status

There are two conditions when auto calibration takes place:

• If on device startup no calibration was detected;
• If the device receives an SMS/GPRS message with auto_calibrate:set text

For the Auto-calibration process you may refer at https://wiki.teltonika-gps.com/view/FMB640_Features_settings#Auto_calibration

For further understanding on how the accelerometer calibration works you may refer at

https://wiki.teltonika-gps.com/view/FMB640_Accelerometer_Features_settings#Accelerometer_Calibration

Please let me know if this helps.

Kind Regards.

Comments

Thank you for your answer, 

you say " If the device has been calibrated, we can sent an SMS (auto_calibrate:get) to check if the calibration is successful." so not obligated?

it makes sense that the harsh events are only send when the accelerometer is calibrated, as long as it is not calibrated it will not send the harsh events, so when I start receiving the events, I know the accelerometer is calibrated... so I don't care about sending the SMS to know if it is calibrated. After a new installation, I don't care if it takes up to a week to get calibrated, as long as I know that it will be calibrated and sending out the harsh events.

I tested some more, and i also see a big difference between the green driving events with source GNSS and with source accelerometer, it is more sensitive with GNSS compared to accelerometer. a very big difference: cornering with GNSS: making a 90° turn at 30km/h: event true. even at 25km/h.

With accelerometer: turning same corner 90° at 50km/h no event even not at 60km/h... with the same standard settings!

thats normal?

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Hello Keon,

Thank you for the response.

1) you say " If the device has been calibrated, we can sent an SMS (auto_calibrate:get) to check if the calibration is successful." so not obligated?

It is not obligated but it is recommended so that you will be aware off the calibration if was done successfully. Also, this is a way of communicating with the device to know if the calibration was successfully.

2) I tested some more, and i also see a big difference between the green driving events with source GNSS and with source accelerometer, it is more sensitive with GNSS compared to accelerometer. a very big difference: cornering with GNSS: making a 90° turn at 30km/h: event true. even at 25km/h.

With accelerometer: turning same corner 90° at 50km/h no event even not at 60km/h... with the same standard settings!

thats normal?

GNSS and accelerometer sources are completely different. You may choose between GNSS and Accelerometer based on the route and the availability of satellites in that route. GNSS source depends heavily on the quality of GPS signal, so if it is poor, it may not be very accurate so it is better to select Accelerometer source in this case as it is more accurate since its inbuilt in the device. Thus, it is best that you calibrate it and fine tune according to your needs.

Please let me know if this helps.

Kind Regards.