Thommen AD20 - 4.1.6.2 Discrete I;Os; 4.1.6.2.1 Discrete Inputs; 4.1.6.2.2 Discrete Input Functions; 4.1.6.2.3 Aircraft Type Selection

REVUE THOMMEN AG
CH-4437 Waldenburg
AD20 Standby Altimeter
Page 56 of 72
07-Sep-2009 Document No: AD-INSOP-800 Revision: 1.6
4.1.6.2 Discrete I/O’s
4.1.6.2.1 Discrete Inputs
Five (5) discrete inputs are available. The use and logic of the discrete I/Os are parametrical.
Voltage level 28 VDC power supply
‘High’ >= 18.5 … <= 36 VDC acc. to ARINC 706-4 section 4.11.4
‘Low’ >= 0 … <= 3.5 VDC
Table 4-11 Discrete Inputs Voltage Levels
4.1.6.2.2 Discrete Input Functions
No. Discrete Input Functions Description Activation (default)
0 n/a No function --
1 TEST (EXTERNAL) Performs a restart of the
instrument
high = Normal
low = activate initiated BIT
2 Battery activation Activates internal Battery as
emergency Power Supply
high = Normal
low = activate internal Battery
3 A/C Type - A Selects aircraft type high = (refer to 4.1.6.2.3)
low = (refer to 4.1.6.2.3)
4 A/C Type - B Selects aircraft type high = (refer to 4.1.6.2.3)
low = (refer to 4.1.6.2.3)
5 Day/Night switch Controls lighting in emergency
mode
high = Night operation
low = Day operation
6
Metric Unit Selection Bypasses unit button and
selects Metric units only
high = unit button selection
low = metric only (hPa / m)
Table 4-12 Discrete Inputs Functions
Note: The functions shall be assignable to discrete input pins by parameterization.
4.1.6.2.3 Aircraft Type Selection
The instrument shall detect by pin strapping in which aircraft it is installed. Preset A/C specific
parameters for VMO/MMO and lighting characteristics shall be used. Two discrete inputs shall be
used to detect the A/C Type. The function shall be assignable to the discrete inputs.
Aircraft Type
Discrete Input A/C Type # 0 A/C Type # 1 A/C Type # 2 A/C Type # 3
A/C Type - A High (open) High (open) Low (ground) Low (ground)
A/C Type - B High (open) Low (ground) High (open) Low (ground)