Drift in PTZ locations

[bcollins]

I'm using onvif with an axis ptz camera to try and point the camera at specific pan and tilt coordinates
I've found however that between every movement there is quite a bit of drift in the 'zero pan' point.
for a short movement this can be around 1 degree, and for longer movements up to 20 degrees.

I'm not sure why this is happening but I was hoping someone might have a solution suggestion?

Cheers

 

[The Automation Guy]

While I haven't used Axis PTZ cameras myself, I've seen tiny errors in the device's motor "accuracy" add up over time. A tiny error on each movement can quickly become add up to a much larger error if the camera is moving a lot. If/when it gets bad, you can reset the location accuracy by rebooting the device which forces the device to find its "home" position again.

If you are saying that a single longer movement can be off by 20 degrees by itself (ie not tiny variance that eventually added up to a 20 degree error over time), then there is something wrong with that camera IMHO.

 

[fastline12]

I will go on nothing but a hunch but being an industrial automation guy, I would suspect the movements may be via 'stepper motors' rather than proper servo/feedback encoder systems....to cut costs. the problem with open loop stepping is there is no report back to indicate to a controller if the desired position was obtained. It's called 'missing steps', and a common issue there is binding of the mechanism. So....you might see if you can find a way to ensure the mechanisms are free. I could see sand or dirt in gear teeth being a big issue.