User's Manual Part 2

T
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CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
4--75
(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
Vdc when sinking 500 mA of current and an output voltage of ≤ 1.5 Vdc 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 Vdc and ≥100k
Ohms to ground for voltages applied to the output of +33.0 to +36.0 Vdc.
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.
D. TAWS/RWS Input Data Signals
The T
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CAS TAWS/RWS functions requires a minimum set of data that is needed to
perform within the standard specifications (detailed in RTCA DO --161A [GPWS],
TSO --C151a [TAWS] and TSO--C117a [RWS] ). This section contains the minimum set of
TAWS/RWS data signals and the information/guidelines that is needed by the installer to
obtain the correct analog or digital signal on a specific aircraft. Since the TAWS/RWS I/O
function is very flexible, the installer must keep in mind that the data signal sources listed
in this section are typical for the specified signal and that the I/O function can be modified
via the ASDB to accommodate other non--typical signal sources.
The information in this section will include External Sensor Input accuracies for specific
inputs to T
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CAS GCAM function. These External Sensor accuracies must be met for the
specified inputs in order for the T
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CAS to perform the TAWS/RWS functions. Inputs to
T
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CAS G CAM function consists of errors due to the external system sensor plus
measurement errors within the T
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CAS LRU. In addition, for analog inputs the internal
T
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CAS errors due to the hardware circuit are also considered.
(1) Vertical Speed (Digital/Analog)
The TAWS/RWS Vertical Speed parameter is updated from an Inertial, GPS or Air
Data Computer source. The IRS/GPS source can be any one of the following :
ADIRS, GPIRS, IRS, AHRS, GPS and ADC.
NOTE: When Vertical Speed is unavailable from an IRS or GPS source, the
alternate variable Baro Altitude Rate will be used from an ADC source.
The minimum External Sensor input accuracy accepted is 68 ft/min when GPS is the
source or 30 ft/min when IRS, ADIRS, AHRS or ADC (alternate Baro Altitude Rate
variable) is the source.