Page 4-6
500 SERIES INSTALLATION MANUAL
Page Rev. B
P/N 190-00181-02
4.3 ALTIMETER
4.3.1 Altimeter
Function
Altitude input is required for GPS RAIM calculations, and is useful for advisory vertical navigation
(VNAV) calculations.
4.3.2
Altimeter Electrical Characteristics
Pin Name
Connector
Pin
I/O
ALTITUDE D4
P5001
70
In
ALTITUDE A1
P5001
69
In
ALTITUDE A2
P5001
68
In
ALTITUDE A4
P5001
67
In
ALTITUDE B1
P5001
66
In
ALTITUDE B2
P5001
65
In
ALTITUDE B4
P5001
64
In
ALTITUDE C1
P5001
63
In
ALTITUDE C2
P5001
62
In
ALTITUDE C4
P5001
61
In
ALTITUDE COMMON
P5001
60
In
These inputs are considered active if either the voltage to ground is < 1.9 V or the resistance to ground
is < 375
Ω
. These inputs are considered inactive if either the voltage to ground is > 18.5 V or the resistance
to ground is > 100 k
Ω
.
NOTE
Some transponders and other altitude encoder receivers do not have internal isolation diodes to prevent the
unit from pulling the encoder lines to ground when the unit is off. These units will require a diode to be
added to the installation harness for each encoder line. The anode should be connected on the receiving
unit’s side and the cathode should be connected on the encoder side. A set of diodes is required for each
unit without internal diodes. The 500 Series unit includes internal diodes for isolation of the encoder lines.
4.3.3
Altimeter Configuration
None.
4.3.4
Altimeter Calibration and Checkout
Refer to section 5.2.7 for the gray code altitude checkout.
4.3.5
Altimeter Interconnect
Refer to Figure 4-6 on page 4-33 for the altimeter interconnect.
