Hi there

I've just finished my new heli's (Goblin Black Thunder) maiden and I've been encountering a significant number of RPM signal too noisy warnings in the logs. The setup is as follows:

1. RPM sensor: Hobbywing phase sensor connected to the motor and powered by the spirit 3.3V sat out port
http://www.fast-lad.co.uk/store/hobbywi ... 30227.html
2. Motor: Xnova XTS 4525-560KV
3. ESC: Hobbywing 130A HV v4 with internal BEC
4. Im using the internal BEC (2x leads) plugged in the Spirit Pro. Also have installed a capacitor on the Spirit Pro just in case the servo's create any back EMF.
5. Servos: BK7006 for the tail and TGY 725 for the cyclic.

I was facing the same issue on the bench when using the HW internal RPM out so I bought a Hobbywing RPM sensor and wired it as per the instructions. Same problem unfortunately . I am using a filter value of 8 but it made no difference.

Also on the Governor tab the RPM is being read correctly and I can't hear any significant fluctuation of RPM's in flight.

I noticed with the internal RPM output I could not use it with the Spektrum Telemetry (TM1000) as I could with the V3 version, I was getting no readings. However with the HW phase sensor I can get readings on the Spektrum telemetry. RPM seems fairly stable on the telemetry and fluctuates slightly on the Governor tab - pretty much the same as with my V3 unit.

I have wired it to use the 3.3V output from one of the spirit sat ports. However the sensor is HV compatible so in theory I could wire it off a servo port? Is that better? Would it cause the Spirit unit to burn out? Or the Spectrum TM1000 unit?

What can I do about it? Thoughts?

If reading is stable enough, you do not have to care until you will see a problem with governor itself (e.g. erratic motor spinning, tail issues or not reacting to the load)
In the upcoming version we have also updated RPM noise detection to be more benevolent where needed and more strict where it is required.
So the measurement will be more accurate and could solve your problem.

You can power the sensor from HV BEC without any problem. It could improve reading stability as well. Hobbywing sensors are rated for min. 3.5V so the signal can be not that clean.

Also telemetry modules can affect sensor reading (or whatever that is transmitting signal).
Putting sensor as far as possible from such sources can improve it.

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Spirit System developer

Perfect thank you. The only reason I powered it from the 3.3v rail was that I was not sure whether it would cause any issues with the TM1000. Would you know if it can accept over 3.3V in the rpm port?

I don't think any current flows there, only the signal...

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