A device that is switched on in the parameters is not ready
What ArduPilot says:
- PreArm: FETtec: …
- PreArm: Generator: …
- PreArm: OpenDroneID: …
- PreArm: Mount: …
Some devices have an arming check of their own. The word before the colon says which one failed: Mount is the camera gimbal (MNT1_TYPE), Generator an on-board generator (GEN_TYPE), FETtec the FETtec OneWire ESCs (SERVO_FTW_MASK), OpenDroneID the remote-identification transmitter (DID_ENABLE). The words after the colon are the device's own reason and have their own explanation.
What to do, most likely first
The device is switched on in the parameters but is not fitted: a parameter file from another aircraft.
FixSet the parameter of the device you do not have to 0 (
MNT1_TYPE,GEN_TYPE,SERVO_FTW_MASKorDID_ENABLE) and reboot.The device is fitted but not powered, not wired, or on a serial port set to another protocol.
CheckMany devices get no power from USB alone. The Board & Wiring Planner shows which port is which.
FixConnect the battery (props off), check the cable, and give its port the right
SERIALn_PROTOCOL; reboot after changing it.The device is still starting: a gimbal finding its centre, a generator warming up, remote ID waiting for a GPS position.
FixWait; the message clears by itself when the device reports ready.
Parameters to look at
| Parameter | What it is |
|---|---|
MNT1_TYPE | Mount Type |
GEN_TYPE | Generator type |
SERVO_FTW_MASK | Servo channel output bitmask |
DID_ENABLE | Enable ODID subsystem |
Where to do it:Board & Wiring Planner
The code that sends it
PreArm: FETtec: …
libraries/AP_Arming/AP_Arming.cpp AP_Arming::fettec_checks() · Open in ArduPilot Copter-4.7.1
PreArm: Generator: …
libraries/AP_Arming/AP_Arming.cpp AP_Arming::generator_checks() · Open in ArduPilot Copter-4.7.1
PreArm: OpenDroneID: …
libraries/AP_Arming/AP_Arming.cpp AP_Arming::opendroneid_checks() · Open in ArduPilot Copter-4.7.1
PreArm: Mount: …
libraries/AP_Arming/AP_Arming.cpp AP_Arming::mount_checks() · Open in ArduPilot Copter-4.7.1