Altimeter setting berserk.

linusbear

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Dec 9, 2007
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KCHD
D100 master with D180, AP74, on power down then power up the altimeter setting resets to highest possible setting (>33 in.). Should it not maintain the last setting prior to power down? How do I correct?
 

Dynon

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It holds the previous altitude (because presumably, you haven't physically moved) and adjusts the altimeter setting to match. But that feature can be turned off under EFIS > SETUP > BARO > ADJUST AT BOOT. If it's doing it every time, though, there might be something up with the altimeter. Is it changing drastically in the first few minutes of being on?
 

linusbear

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Dec 9, 2007
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That seems to correct it, very good, thank you. Your customer service is excellent. Now if I could figure out why the clock on the D100 (master) (no battery backup) always requires resetting on power up. Should the master have a battery back up? I seem to remember while wiring that it was not recommended to connect the stay alive wire. Would that help?
 

Dynon

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So the ideal way to keep the clock from resetting is to install a backup battery. If you do that, you definitely don't want to connect the keep alive wire, as it will recharge the backup battery as it slowly self-discharges over time. This wasn't an ideal design, and SkyView - in contrast - only charges the backup battery when we see a high enough voltage such that we know that an alternator/generator is running.

If you don't have the backup battery, connecting the keep alive line will have much less of an impact on discharging your aircraft battery (I think it's negligible, but I don't know the current draft off the top of my head).

Another way to have the system pick up time is to connect a NMEA GPS via serial. Then, whenever you get a lock, it'll pull that into the system.
 
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