Bad OAT sensor?

[keleher]

I've got an OAT sensor hooked up to a D120. The sensor's reading 100F, while the actual air temp is more like 60F. If I warm it with my hand it'll go up a couple degrees, but that's it. Everything seems to be setup correctly on the D120. Changing OAT sensor types doesn't seem to fix it anyway. I can't find any menu for calibrating the sensor, if that's possible.

I measured 5.9K Ohms between the blue/white and yellow wires (blue and white are connected to the same pin on the connector). I've got another plane here with the same setup and the same resistance (haven't powered it on yet to see if it's acting up also).

 

[keleher]

So, any ideas?

 

[dynonsupport]

Are you sure you're using an OAT made by Dynon? Our two OAT probes have either a pair of black and white striped wires, or red/yellow/blue wires. If you're using the one with red/yellow/blue wires, the yellow should be going to a an GP input of your choice, the blue to ground and the red should remain unconnected (it's only connected if used with a an EFIS's remote compass).

 

[dynonsupport]

5.9K is about right for 100F, by the way. Either it's the right probe and it's bad, or we're not talking about a Dynon OAT probe.

 

[keleher]

I'm not certain who made the probe, but from your description it's probably not a Dynon. It came pre-installed by the factory (it's an S-LSA we're assembling), and the documentation I have doesn't say anything about it.

Is there any way to calibrate the EMS for a different range of resistance values? Or is the existing sensor pretty much useless?

 

[dynonsupport]

The OAT does need to be ours. It looks like this in either case, incidentally:

http://dynonavionics.com/docs/D100_Feature_OAT.html

 

[keleher]

Ours looks similar, but a little different.  My guess is it's a cheap knock-off that wasn't really tested during their 5 hour post-construction, pre-shipping flight test.  Doesn't really surprise me, given the other issues we've had getting these planes ready for certification.

Thanks for your help.  I really appreciate getting a quick, clear answer, even though it's not the one I was hoping for.  Incidentally, you've been more helpful than this particular LSA manufacturer has ever been with any of the other problems we've had assembling or maintaining these planes (this is not our first plane from them, but hopefully it'll be our last).  Given their track record, if I'd went to them first with this issue, I probably wouldn't even have an answer yet, let alone a useful one.