User's Manual Part 2

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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--10
Table 4--1. TT--950/951/952 T
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CAS Computer Unit Interface Description (cont)
Connector Pin
Designation
Functional Description
RMP--12B
(Continued)
Radio Altimeter Type Select Program Input No. 4 (NO)
AHV 6
Log
0.0 to 10.4 Vdc: H = 50V -- 20
> 10.4 to 18.09 Vdc: H = EXP(0.1479V + 4.7289)
> 18.09 to 25 Vdc: H = 695 + EXP(0.2532V + 2.1111)
Were H = Radio Altitude in feet and V = Voltage in Volts dc.
APN
232
0.0 to 27.0 Vdc: H = 200V
Were H = Radio Altitude in feet and V = Voltage in Volts dc.
LPIA
1.0 to 9.0 Vdc: H = 50V -- 50
> 9.0 to 21.0 Vdc: H = 383.14V -- 3048
Were H = Radio Altitude in feet and V = Voltage in Volts dc.
N R -- A S -- 1 0 A
Alternate
0.0 to 1.2 Vdc: H = 2105.7V
Were H = Radio Altitude in feet and V = Voltage in Volts dc.
N R -- A S -- 1 0 A C u r v e
Fit
0.0 to 18.1 Vdc: H = 0.0833V
4
-- 1.8887V
3
+ 15.5169V
2
-- 21.9374V + 14.8097
Were H = Radio Altitude in feet and V = Voltage in Volts dc.
Each of the military radio altimeter types provide two outputs that are connected to the
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CAS computer unit input pins. The two altimeter outputs are the Analog Data Output
and Analog Data Reliability Signal. The Data Reliability Signal is connected to RMP--2K
for source No. 1 and RBP--3C for source No. 2, except for altimeter type LPIA. For radio
altimeter type LPIA, the Analog Data Output must be connected to RMP--2H (HI) and
RMP--2J (LO), the Analog Data Reliability Signal must be connected to RBP--3A (HI) and
RBP--3B (LO), and the inputs RMP--2K and RMP--3C are set high (greater than 18.5 V).
The metric radio altimeters are defined as follows:
Metric
Altimeter Definition
No. 1 Metric unit-- 1000 meter range, 25 mV/M scaling
No. 2 Metric unit-- 1000 meter range, 20 mV/M scaling
No. 3 Metric unit-- 1500 meter range, 20 mV/M scaling
No. 4 Metric unit-- 750 meter range, 50 mV/M scaling