User's Manual

Table Of Contents
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
T
3
CAS/Part No.9005000
The discrete inputs source 1.0 ±0.25 mA of current when the input is
grounded and has diode-isolation circuitry to prevent the inputs from
being loaded to ground when power is removed from the T
3
CAS.
NOTE:
When an input goes to a discrete on both TCAS and
TAWS/RWS, the input current is twice the specification for a
single discrete.
(b) Discrete Input +28 V dc/Open
T
3
CAS provides +28 V dc/open discrete inputs for aircraft level discrete
interfaces. The +28 V dc and OPEN logic states are determined per the
following:
+28 V dc ≥14.0 V dc at the input.
OPEN ≤ 3.5 V dc at the input OR a resistance of greater than 100k
ohms to the positive voltage source.
The discrete inputs sink 1.0 ±0.25 mA of current when a +27.5 V dc input
and has diode isolation circuitry is applied to prevent the inputs from
being loaded to ground when power is removed from the T
3
CAS.
NOTE: When an input goes to a discrete on both TCAS and
TAWS/RWS, the input current is twice the specification for a
single discrete.
(c) Discrete Output Ground/Open 500 mA
The discrete outputs listed in this section pertain to ground/open discrete
outputs for the TAWS/RWS function.
The discrete output in the GROUND logic state has an output voltage of
≤3.0 V dc when sinking 500 mA of current and an output voltage of ≤1.5
V dc when sinking 100 mA of current.
The discrete output in the OPEN logic state has an output impedance of
≥ 2.4M ohms to ground for voltages applied to the output of 0.0 to +33.0
V dc and ≥100k ohms to ground for voltages applied to the output of
+33.0 to +36.0 V dc.
The discrete output circuitry contains a monitor which detects if an over-
current condition has occurred and is able to withstand a direct short to
+28 V dc for an indefinite period of time.
Additionally, the discrete output circuitry contains a monitor which
detects if the output voltage is incorrect for the driven state of the
discrete output.
This section defines the DO-260B Configuration Pins. Table 4-17
outlines the connections necessary to set the DO-260B configuration
data. Refer to Table 4-18 for definitions of the DO-260B configuration
settings.
4-116
04 Nov 2014
34-45-29
Pub. No. 8600200-001, Revision 004
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