Hi,
I am working on an custom Hexacopter Agri-drone build, which uses the Pixhawk 2.1 Cube as the Flight Controller and the Hobbywing Xrotor X8 Pro propulsion system.
Manual: https://cdn.shopify.com/s/files/1/0109/9702/files/ComboX8en.pdf?2563893437545155760
The Cube is loaded with Arducopter firmware [version number : 3.6.9].
ISSUE:
The Cube doesn’t pass the throttle PWM signal after DIS-ENGAGING the safety switch [refering to the Steady Red colour on the LED present in the Here GPS module].
ESC Calibration: This was done for each motor individually by connecting the ESC to the throttle channel of the onboard Radio Reciever Module as the Mission Planner/Pixhawk Cube “All-at-Once” calibration didn’t work.
Radio Calibration: Successful… no difficulties
Throttle Failsafe PWM value: 975
TROUBLESHOOT ATTEMPTS:
-
Using Mission Planner, the “Servo Output” feature under “Mandatory Hardware”, I passed the raw “throttle input signal(RCIN3)” to each of the motors and they responded perfectly to the throttle INPUTS provided. After re-starting the Cube, I passed the “Throttle Output signal(THROTTLE)” to each of the motors, but, the ESCs kept beeping in manner indicative of no Throttle Signal [ the Safety switch was DIS-ENGAGED].
-
I checked the “RC_SPEED” parameter to ensure the time interval between two consecutive SERVO output signals is greater than 0.25 seconds, so that the ESC’s “Throttle Signal Loss Protection” isn’t getting activated. [I have attached the link to the manual for the ESC]
-
I modified the minimum SERVO output value for each of the “MAIN OUT” ports connected to the motors. The minimum PWM value was set to 1100, as that is the minimum value of the thottle range for the ESC.
-
I checked the option for “Throttle signal” to be sent by the Cube when dis-armed and the SAFETY SWITCH is DIS-ENGAGED.
Area of DOUBT:
The connection for this build was unusual, because, I have always connected the FC and ESCs in an electrical manner which TURNS them ON at the same time when the Flight battery is connected. However, for this build the ESCs which I have decided to use require a 12S LiPo battery as input and we know that the “Power Brick mini” for the CUBE can handle upto 8S LiPo battery input only. So, my PDB has an option to take power from either the 6S or 12S ports and I am using two 6S LiPo batteries connected in “series” so as to generate the required 12S for the ESCs. The CUBE’s power module is connected to the 6S port on the PDB and as such when the batteries are connected to the PDB, the CUBE is turned ON first and then the ESCs turn ON, due to the slight delay in connecting the TWO separate battery leads. I feel this maybe interfering with the initialisation process of the CUBE and that’s why the FC Throttle output signal is not being passed to the ESCs.
Is there something else that I may have missed.
Thanks in advance for your help and patience.
PDB used: https://www.droneassemble.com/product/power-distribution-boards-for-16l/