More testing. More Interesting results. Why I want an oscilloscope for Christmas
I ran through some additional test cases this morning with some interesting results.
Test Cases Evaluated:
1) Trying a different non-SRXL2 receiver
2) Trying a different Spektrum transmitter
Steps Taken:
Trying a different non-SRXL2 receiver
1) I bound a spare SPM9645 DSMX Satellite receiver to the original TDSF model in my transmitter which was previously bound to the SPM4651T. The SPM9645 was connected to the Sat1 port on the Spirit2
2) I powered up the Sprit2 with a receiver back and reconfigured it for DMS2/DSMX in the General tab. Saved my settings and rebooted the Spirit. Servos worked normally.
3) I re-entered the Spirit2 configuration and assigned the throttle channel so channel 1, saved and reset the the Spirit2. All saved successfully.
4) I powered up the Kolibri/Spirit2/SPM9645 with a flight pack. The esc would not arm, single flashing LED as always..
I walked away from that test scenario thinking that changing the RX made no difference.
On to the next test.
Trying a different Spektrum transmitter
1) I left the SPM9645 connected to the Spirit2. I put it in bind mode (binding through the Spirit2) but this time, I bound it to a new model on my Horus X12S running OpenTx with an iRangeX + module. All bound fine. Servos worked, I powered down
2) I removed the bind plug and powered the Kolibri up with a flight pack and voila, the esc armed! Tones, cell count, all fine. I made note that on the Horus (According to OpenTX), the PWM at low throttle was 966us.
This was really interesting to me. I had not changed the PWM settings in the Throttle section of the Spirit2. It was set at 1100us Low but it armed.. I thought about how the low throttle PWM from the transmitter might affect the arming of the ESC. The Spirit2 documentation is clear that you need to be sure that in the diagnostics tab, your throttle shows 0-100 travel. Mine has always been configured that way. My Kolibri will not arm with the SPM9645 (this is important later) unless the throttle travel is -7.
More testing (can I get it to arm with my Spektrum transmitter):
1) I haven't found a way to see the PWM output for a given servo travel setting in Airwave so I attempted an educated guess. Based on an article I found online on Spektrum receivers, the Mid should be 1500us to 1520us depending on the rx. A little math gave me the travel I'd need to set the transmitter to to output roughly 966us that my Horus sent.
2) I set my Spektrum transmitter to a low throttle travel of 112
3) I powered up the Kolibri, Spirit2, SPM9645 with a flight pack and.... It armed. Interesting...
This has me wondering.... Does the Spirit2 simply pass the throttle signal from the receiver through to the esc? OR... Does the Spirit2 look for a specific low throttle PWM before it will send any signal to the esc. If the Spirit2 does pass the throttle signal through, is there some scaling factor that may be shifting what the esc is seeing. Admittedly, this is just a wild theory but it might explain why the esc will now arm without any changes to the PWM range in the throttle setting on the Spirit2. The only PWM change was on the transmitter.
If only I had an oscilloscope to see... Santa... If you're listening... Of course unless there is a scaling issue, this doesn't explain why the servo I plugged into Aux1 on the Spirit2 worked.
More testing (With the new throttle travel, will it work with the SPM4651T):
1) I replaced the SPM9645 with the original SPM4651T, Bound the SPM4651T to my Spektrum transmitter (same model, same settings).
2) I powered up the Spirit2 and SPM4651T with a receiver pack and configured the Spirit2 to use SRXL2. Settings saved successfully. I powered down.
3) I powered up and set the Spirit2 Throttle channel to channel 1. Saved settings. All servos worked normally. I powered it down.
4) I powered up the Kolibri,Spirit2,SPM4651T with a flight pack. Even with the throttle travel set to the same low setting I used successfully with the SPM9645, the esc wouldn't arm, no tones single flashing light.
So maybe there are a couple of issues? Maybe the Spirit is expecting a specific PWM range from the receiver before it will arm the throttle? Maybe the SPM4651T and the SPM9645 receivers produce different outputs at any given throttle position?
Going to try another 4651T next.
All thoughts and insights are greatly appreciated. I do hope that others are finding this as interesting as I am.
-Eric