Telemetry RPM counter

Hello Everybody,

I just found that the RPM input of the Walkera telemetry module may has an 8bit counter that shows overflow over 255 edges. It means the highest RPM value 120x255=30600. Is this problem caused by the telemetry module (so, the module has an 8bit counter), or is it cased by the Tx with the Devieation FW 4.0.1 on it (so, the bottleneck is the Tx)?

Thanks for the help. Regards,

Istvan

Hello Everybody,

I also found that with my Walkera RPM sensor, it shows about 10% lower value than it is.
So instead of 3000 RPM the sensor measures 2750 RPM. I think I'm going to develop an other sensor and calibrate with my lab equipments.

Best regards,

Istvan

telemetry.h has u16 variable, which means max 65635.

devo_cyrf6936.c:
Telemetry.p.devo.rpm[0] = packet[7] * 120; //In RPM
Telemetry.p.devo.rpm[1] = packet[9] * 120; //In RPM


To me it seems there is no 0xFF/u8 255 limit.


I changed head/default for DSM telemetry from u8 variables to u16 and now the flightlog fields correctly display up to 9999 instead of 255.

So I guess as you the 255 packet limit is already set from the devo telemetry hardware?

Greetings

Thomas

Thanks for the answer.

This is what I was afraid of.
The overfow caused int the telemerty module :-/

For the head speed it is ok (with the awesome 120RPM resolution)
But the motor RPM owerflows at 30600 RPM.
Not a big deal, I can do the math.

Thanks again.

Can we add the pinion and main gear ratio to a configure DeviationTX screen so the real head rpm is displayed in telemetry view as suggested in other threads?