GE ADTS 542 Instruction Manual page 66

Ps, Pt and Qc
The following controls are available when "Pressure" units are selected:
- Ps (Ps1, Ps2 on ADTS553/554)
Displays the currently selected pressure. To change the pressure value:
1) Touch the "Aim" value (1) to highlight it, a numbered keypad is displayed.
2) Use the numbered keypad to input the new value.
3) If required, change the rate of change value by touching the "Rate Aim" value (2) and input the
new value, or use the nudge up/down controls (5/6) to increment/decrement the value by a
pre-defined factor.
4) Touch the "Tick" icon (3), the new value appears in the "Aim" field. The Ps value changes to the
new value, at the rate of change value, and provided that the new value is within acceptable
limits the Ps text will turn green
5) Touching the "Cross" icon (4), cancels the action and closes the keypad.
- Pt (Pt1, Pt2 on ADTS554)
Displays the currently selected pressure. To change the value, repeat the same procedure as Ps (Ps1,
Ps2 on ADTS553/554)for Ps.
- Qc (Qc1, Qc2 on ADTS554)
Displays the currently selected pressure. To change the value, repeat the same procedure as Ps (Ps1,
Ps2 on ADTS553/554) for Ps.
Altitude Dropback
The ADTS550 series products use a single set of pumps to generate the internal pressures and
vacuums which are ultimately presented at the Static and Pitot ports. During control situations where
high gas flows are required, it is possible for these source pressures to start to collapse. This can mani-
fest itself as an unwanted drop in altitude on a channel that was previously under control and stable.
To prevent this effect, the software inside the ADTS will limit the CAS or Altitude rate changes to main-
tain a non-ramping (stable) channel.
: In extreme cases the rate limiting effect can make altitude and CAS changes appear very slow.
NOTE
P S
ITOT TATIC
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