HIL pwm registers unchanged


I’m trying to set up HIL testing but am having some trouble. I put the PX4 in HIL mode using QGroundControl’s “HIL Config” widget and the Pixhawk status light is green. However, the values sent in HIL_CONTROLS and HIL_ACTUATOR_CONTROLS messages are unchanging.

  • Using 3DR Pixhawk hardware
  • using fixed wing airframes
  • same behavior with firmware v1.4.1 and current master
  • same behavior using different mixers and airframes

I traced the issue down to the fact that the values in the messages published on the actuator_outputs uORB topic are not changing. I believe messages get published by px4io.

From looking at log files, the attitude controls are being set to reasonable values, but the actuator outputs (OUT0_OUTn in log files where n is 0 to 7) are always set to 0 except for OUT0_OUT4= 1000. This makes me think that the mixer isn’t actually operating? (or at least, the servo output registers aren’t being set.)

On startup, PX4IO crc check is ok and the mixer loads successfully.

Any input would be appreciated. Thanks!