
CM170407AMA
•
When the MPS49 is in the CONTROL mode of operation.
•
When the airspeed/AoA commanded value is zero.
•
When the pressure inside the static line is very close to the ambient pressure.
•
When the pressure inside the pitot/AoA line is almost the same as that in the static
line.
•
When the altitude rate is close to 0 feet/min (or the Ps rate is close to 0 hPa/min).
Once the equipment satisfies these conditions:
•
the
AoA auto-zero
is automatically activated; the Operator should wait until the
differential pressure is almost equal to zero before commanding new AoA values.
•
the Operator may enable the “Ultra-low speed function” to enhance the resolution at
very low
airspeeds
.
NOTE
the AoA auto-zero may be disabled from the Settings Menu. Refer to the MPS49
Calibration and Adjustments Manual for more information.
The ultra-low speed function can be enabled by entering the Main Menu (
SHIFT
+ 3) and
selecting “Functions” and then “ULS”. As long as the function is active, the air speed
resolution is increased as described in the following table, and the Status Screen displays
“ULS” in the lower-left corner.
Normal
Ultra low speed
Minimum measured speed with 1 knot resolution
10 knots
2 knots
Minimum measured speed with 0.1 knots resolution
20 knots
50 knots
As soon as the altitude significantly changes, or any other of the above conditions are no
longer satisfied, the MPS49 will automatically exit the ultra-low speed function.
NOTE
The airspeed rate command is not enforced while in ULS mode.
7.5 ENCODING ALTIMETER (OPTION)
An optional front panel connector is used to connect the Encoding Altimeter or Encoding
Device, to test the altitude reporting Gray code. Any unit can be tested, if a proper cable is
prepared.
NOTE
the last page of this manual contains the wiring diagram for the adapter cable to
connect the UUT to the MPS49.
When an Encoding Altimeter/Encoding Device is to be tested, connect it to the MPS49,
before the ADTS is powered on.
To start a test of the encoding altimeter, press the orange button Enc on the Status Screen.
The MPS43 will switch to the Encoding Altimeter Test Screen (FIG 12).
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