You have to correct the local barometic pressure for altitude and other factors. I have a chart at home on the corrections. If you don't get an answer soon, ask me and I will try and bring it with me to send next time I can get to a computer. My home Dell hardrive (3 years old) blew up with the os on it so I am remote.....
Marc Wiese
>
> From: "Al Gietzen" <ALVentures@cox.net>
> Date: 2004/08/25 Wed PM 05:38:55 GMT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] EM2 users
>
> Now that I have returned from vacation, recovered from an Airline induced
> cold, and caught up on other tasks; I can get back to the airplane.  Tracy
> was prompt in diagnosing and adding a filter to solve the EM2 display
> problem, and I have it back up and running.  That leads to a lot of other
> questions - lucky for him he's on vacation, so I thought I'd get some
> comments from other users.
>
> So far just sitting with engine off, I'm observing some anomalies, and
> wondered whether other users see the same.  
>
> Local barometric pressure is 30.02, so I expect it to give me this number as
> MP.  With EC2 turned off it reads MP as 29.2 - I assume it is reading this
> with the sensor in the EM2.  With EC2 on (data feed from EC2) it reads 32.3.
> Neither of the readings is correct.  Should I be concerned?
>
> Battery voltage reads about .75 lower than my voltmeter reads at the
> breaker.
>
> The RWS air temp sensors (I have 3) all read 6-8 degrees lower than actual
> air temp (75F at the time).  I expect these should be accurate.  The J-type
> TCs read right on air temp. The K-type TCs are about 5-7 low at ambient
> temps, that doesn't really matter.
>
> Oil and coolant temps were somewhat off, but I adjusted calibration factors
> to get them about right.  But didn't quite know whether to change 'Low end
> offset' or the 'Sensor offset'.  I assume for the VDO sensors the scale
> factors are correct.  The more general question on temp calibration is,
> short of taking out the sensor and putting it in boiling water, what's a
> good (read easy) way to get another reference point at something like
> operating temp?
>
> Anybody using 'Aux Liquid temps' 2&3?   Mine aren't working right.
>
> Al (anxious to make some more noise)
>
>
>