Pixhawk无人机教程-7.5.2 PX4 Analog Pins

PX4 Analog Pins

---

The PX4 has the following “Available” Analog input port pins which may be put to a variety of uses.

PIN = 10 High Voltage Analog pin.

Located on pin 5 of the DF13 15 pin “multi-connector” of the PX4FMU board.
This pin can accept up to 18.6 volts.
With the Advanced Parameter VOLT_DIVIDER set to 1 voltage can be read directly.

For old releases VOLT_DIVIDER needed to be set to 5.66 for direct voltage scaling.

PIN = 11 The “airspeed” pin.

Located on pin 2 of the 3 pin “FMU-PRS” DF13 connector on the PX4IO board.
Generally used in APM:Plane for the Air Speed Sensor with VCC on pin 1, Sensor on pin 2 and Ground on pin 3.

APM:Plane Advanced Parameter: ASPD_PIN set to 11.

This pin is directly connected to the ADC on the PX4FMU.
This pin can accept up to 6.6 volts (it has an internal voltage divider).

PIN = 12 A general analog input pin.

Located on pin 3 of the “FMU-SPI” port on the PX4IO board.
Commonly used for Sonar

APM:Copter and APM:Rover Advanced Parameter: SONAR_PIN set to 12

This pin is directly connected to the ADC on the PX4FMU.
This pin can accept up to 3.3 volts.

PIN = 13 A general analog input pin.

Located on pin 4 of the “FMU-SPI” port on the PX4IO board.
Commonly used for Sonar 2 in dual Sonar installations.

APM:Rover Advanced Parameter: SONAR2_PIN set to 13

This pin is directly connected to the ADC on the PX4FMU.
This pin can accept up to 3.3 volts.

PIN = 100 A virtual analog input pin for voltage of a battery connected to the 6V to 18V input of the PX4IO voltage regulator.

This is the normal pin to use for LiPo monitoring on the PX4IO.
If using this pin then set VOLT_DIVIDER to 1 for correct battery voltage reading.

PIN = 101 A virtual analog input pin for a battery current sensor connected to the “current” pin next to the power connector on the PX4IO.

This pin can accept up to 3.3 volts.
WARNING: If voltages higher than 3.3 are used there is a risk of causing the PX4IO to malfunction, forcing the PX4FMU to reboot.
For use with a current sensor, a 0.1uF capacitor between this pin and ground will help reduce “noise”.