I am using an IRIS+ running arducopter 3.3.3 with a MB1242 I2CXL-MaxSonar-EZ4 sonar and I am attempting to get the drone to hover indoors (I plan to add a px4flow as soon as I get this working). When I take off in Alt-Hold with the Sonar disabled (connected or not), everything works as expected. However, when I enable the sonar it stops working.
I can arm the drone just fine and I have control of the throttle just like normal until I cross 60% throttle, which is the end of my dead zone. Once I pass it, I completely lose the ability to control the throttle and the only way I am able to shut the motors off is to use the motor emergency stop on channel 7. If I leave it running it will usually just stay on the ground, but once it suddenly took off and crashed into the ceiling. This was not the longest I had let in run.
I have also noticed that when the sonar is enabled, as soon as the drone is powered on, the climb will grow until it reaches about 300 m/s and the altitude (REL) will increase until it maxes out at 40,000m. I think this is related to the issue, but I am unable to figure out exactly what the problem is.
I've attached a graph of the throttle channel of my controller and the actual throttle. You can see the point where the throttle suddenly drops and I lose control. I created this by running the drone on the ground without props, but very similar things happen with props on. I've also included a graph of Alt (REL) and Climb while the drone is just sitting on the ground. Ignore before the mode change. That is when I rebooted.
Thank you in advance for your help.
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