I am running APM using a separate power source(a 2S lipo) on the aux power lead(unsoldered SJ1 blob jumper). I have realized that if I disconnect power from this connection, I lose all control of the servos.
The failsafe document says I can reprogram the failsafe to a PPM Multiplexer Failsafe(so that I can still retain manual control of the aiplane in case the APM board is powered off). Here is a snippet of what I am talking about:
"This feature allows you to "hard" route the four main input channels (Ch1, 2, 3 and 4) to the outputs (Ch1,2,3 and 4), by using any defined input channel (In the same PPM encoder source code header)... This is useful in development stages when the Autopilot may freeze or crash (It will work even if the microcontroller is dead)."
How can this be done? The instructions are not clear as to how to do this. Do I need to reprogram the encoder or is this a setting in the APM-config.h file(which I do not see).
Thanks for your help in advance.
Did anyone ever answer your question or did you figure it out yourself? I'm pretty confused right now about how each of the failsafe modes work. So I'm experimenting by using the Arduplane simulation with X-Plane. It's easy to program a failsafe configuration om my Optima 7 receiver so that it tells APM to go into RTL mode. But the confusing thing is the PPM Multiplexer Failsafe. I guess the HW that does the multiplexing is another Atmel processor. So if the autopilot processor crashes, the mux processor is supposed to connect your RX outputs directly to the servos (as long as it doesn't crash too!).
No. I never got it to work. All I ended up doing is having redundant battery connections to APM so that it would never lose power.
I meant to add that I'm not sure if the mux processor code is loaded along with the autopilot code each time you upload a new APM version. And I'm not sure if it's permanently set up to always switch the servos over to the receiver or if there's something the user should set up as well. It SEEMS like it works when I press and hold the reset button on the IMU Shield - that obviously stops the autopilot processor. When I do that, the radio USUALLY has direct control of the servos. I say 'usually' because there have been times when I NO control at all after pressing reset. It doesn't leave me with a very warm feeling!