Multiplex, SRXL and Spirit V2

[martinm]

Hi

I just replaced my MicroBeast by a Spirit unit on my Trex500, and I'm struggling with configuration.

Hardware:
TX: Multiplex Profi 16, Firmware 3.56 (RF firmware version: 1.72)
RX: Multiplex RX-7 MLINK, Firmware 1.38, SRXL V1 output activated
Flybarless controler Sprit V2 Firmware 2.6.4
Installation: horizontal 0°
Head configuration : CCPM 120°
Servo connections CH1,CH2,CH3 triple checked

On the transmitter all mixers are disabled, and all channels output a linear (-100..+100%) signal. I checked with the transmitter integrated servo monitor. But on the Spirit side, channel readings are a bit weird. TX channel 4 seems to be skipped, TX channel 5 is mapped on spirit channel 4, TX channel 6 is mapped on Spirit channel 6. Elevator (collective) is reversed with very limited range is 118..0%, Pitch channel is reversed with limited range 118..-68%, see table bellow

Code: Select all

TX channel | Spirit channel |       mapping         |  status   /  range
       1            1                Aileron            ok, -107..+107%
       2            2         Elevator (collective)     reversed  118..0%
       3            3                Rudder             ok, -107..+107%
       4          ignored 
       5            4                Gyro               ok  , -92..95%
       6            5                Pitch              reversed  118..-68%

Actually the Pitch and Elevator (collective) signal range seen by the spirit unit seems to depend on the Collective position on the TX when the model is powered up:

Code: Select all

TX Collective initial    | Spirit Elevator   |  Spirit Pitch 
position at power up     | (collective)range |     range              
   -100%                      0..-118             74..-118
      0%                    108..-106            109..-104 
   +100%                    118..   0            118.. -68  

After setup, all axis are moving in the right way. When moving the model, aileron and rudder are properly compensated but:
- Collective is slow to respond
- When moving the model on the pitch axis, the unit respond by adjusting collective (!?)


Am I missing something ? Was the Sprit V2 tested with Multiplex gear ?

A worried customer.

[martinm]

Sooo... no idea/suggestion ?

Just in case, I upgraded to firmware 2.7.0, it didn't magically fix the issue.

[ZeXx86]

Hello,

Are you able to change mapping in the radio?
The best is to leave Spirit Channel mapping at default.

Collective Pitch position should not affect anything if it is really mapped as Collective Pitch.
But Aileron, Elevator, Rudder is used for automatic calculation of the channel center for Collective Pitch. So if they are mapped improperly too, correct center will be calculated improperly too.
So the only thing that is necessary is to set mapping properly and reboot the unit.

Are you able to change any SRXL parameter? For example how many channels are transmitted? This could help with transmission speed.

The problem when you are moving with elevator axis is caused by incorrect servo connection and/or servo reversing. Firstly it is super important to make the Diagnostic tab look correct, including channel directions.
Then connect the Servos according Diagram that is in the Spirit Settings. Then use Servos/Servo Reverse to set correct servo movement direction - when changing collective pitch all servos must move together and in the right direction. It is identical to Microbeast except labels are different.

[martinm]

Hi ZeXx86

Yes, I can change the transmitter mapping, this is actually the first thing I tried, here is the TX side:

and the Spirit side:

Note that I had to skip the channel 4 on the TX, because the Spirit unit doesn't see it.

As far as I know, I cannot change any SRXL parameter: I can only choose between SRXL v1 and SRXL v2 (I tried both, V2 is worse)

I adjusted channel direction in the TX to make sure they are right in the Diagnostic tab, but in the end, Longitudinal and Collective movements just make no sense. The Longitudinal is reversed and not properly compensated and collective is reversed. Checking the "reverse collective direction" checkbox actually reverse the Longitudinal . Looks like the unit is mixing up Longitudinal and Collective

Just to be sure, in the Spirit UI:
Aileron = Cyclic Lateral (equivalent to aileron on an plane)
Elevator = Collective pitch
Rudder = Yaw
Pitch = Cyclic longitudinal (equivalent to elevator on a plane)

[ZeXx86]

First step is to make sure all channels are moving in the right direction in Diagnostic tab.
Is this OK? At this point please do not observe Servos at all. It does not matter what servos are doing.

After this step do not touch any settings in your radio, especially channel reversing or mapping.

Only once Diagnostic tab is looking good, then start to change servo reverse in the Servos tab.
Reverse servos so that all servos are moving coherently when moving with collective stick.
So at this step the only error could be in the Servo tab or servo wiring (CH1/CH3 not connected according swashplate diagram).

[martinm]

Ok, I figured it out: I got confused by Spirit's channel names "pitch" and "elevator" and inverted them, for future reference here is which is what:

I suggest that in the Spirit UI, "Pitch" is replaced with "Collective". "Pitch" is very confusing because it is also an Axis name:

pitch-axis.png (12.93 KiB) Viewed 587 times

I still have the ignored channel 4 problem, but I can probably live with it.