Thanks for reading.
We are having problems with the RCIN port of the Pixhawk for the purposes of passively logging servo signals via a PPM encoder.
The intention is to be able to quantify the actual control inputs to the helicopters control system. There is a 3GX stabilisation system – this means that the user’s control inputs do not necessarily reflect the actual servo signals.
For this reason, we have set up a breakout between the 3GX and Servo cables. This is a connection in series with the intention of not disrupting the 3GX to Servo signals. The breakout passes through a PPM encoder and then in to the RCIN port of the Pixhawk.
The problem is that in the data downloaded all the entries of RCIN remain at exactly 0 (apart from the timestamp and datapoint number).
Does anyone know why this might be the case? We definitely have a PWM signal coming from the breakout passing through the PPM encoder.
Many thanks for any help!
Is the PPM encoder a 3DR PPM Encoder?
If it is, then is the blue led flashing?
It is the PPM Encoder V2.0 for Pixhawk.
amazon.com/Hobbypower-Encode … B00HCA40HA
The blue LED remains constant.
Since it is a clone you never can tell what firmware it might be loaded with or how it will function.
If the PPM Encoder is working properly the blue led will flash. If it flashing very fast or always on this document will tell you what is wrong http://3drobotics.com/wp-content/uploads/2014/01/PPM-Encoder-V3-Manual.pdf
Ok thanks for your help.
May I ask another question? The 3GX outputs are: Aileron, Elevator, Pitch, Rudder, Throttle.
The fault code indicated by the flashing light suggests that the Throttle cable is critical. We haven’t yet tested the set up with all of these connected since the cables haven’t arrived. Do you think that this should work with the throttle attached too?
We tested just using the outputs from the receiver on the heli and found zero log.
Pitch and Elevator are the same. Do you mean the Pitch of the rotor blades?
The Pixhawk usually expects: Ailerons, Elevator, Throttle, Rudder and then the rest of the channels that are left.
On the rotorcraft model there are three servos controlling the swashplate. These are defined as the pitch, elevator and aileron servos. I’m aware that these words don’t really make sense for rotorcraft but it is just how they are defined. See the Align 3GX on google images for clarity.
Shall test a new PPM encoder and full system now that cables have arrived.