Sonar fails pre-arm check

Hi All
I’m using a Maxbotix MB1240 rangefinder, however the shortest distance it can do seems to be about 22cm, which is what i expected.
My problem is that it fails the prearm checks, and I don’t really understand why. It seems to work perfectly above 25cm, and I have set the minimum altitude to 30cm, so it shouldn’t be used under that. Could it be failing the check because the reported range (22cm) is incorrect?
Is it possible to disable the prearm check for this?


So the issue sounds like when it’s on the ground, it’s reporting an invalid distance (i.e. a distance below the RNGFND_MIN) so that trips the per-arm check of the range finder. It is possible to disable the prearm check by changing the ARMING_CHECK parameter value. If the mission planner is used, the standard params page should show a number of checkboxes and unchecking “Parameters” will also disable the range finder checks. Sorry, this should be more clear and I’ll update the ARMING_CHECK parameter description in a moment.

Thanks for that! I thought that by setting the minimum distance to 30cm,that the invalid distance of 22cm would be quietly ignored. At about 25cm or greater the rangefinger works fine, but it doesn’t go below a reading of 22cm