-4-
Section 1.0 Introduction
1.1 Scope
This manual provides detailed installation, calibration and operating instructions for Trans-Cal
Industries= Model SSD120-(XX)A-RS and SSD120-(XX)AE-RS
1
series of altitude encoder /
digitizer.
1.2 Equipment Description
Approved under F.A.A. TSO-C88a, the Model SSD120-(XX)A-RS and SSD120-
(XX)AE-RS is an all solid state electronic device which when connected to an
aircraft static and electrical system, converts pressure altitude information into
parallel and serial digital data.
The parallel altitude data protocol is set forth in the (ICAO) International
Standard for SSR Pressure Altitude Transmission. In accordance with U.S.
National Standards for Common System Component Characteristics for the I.F.F.
Mark X (SIF)/Air Traffic Control Radar Beacon System SIF/ATCRBS.
The serial altitude data protocol has selectable resolution (refer to
Tables V
&
VI
and
'
4.6
) and is provided on two (2) RS232 outputs (
TxD1
and
TxD2
) and one
(1)
RS485
output which may be used to provide pressure altitude data to GPS or
other on board navigation devices. The RS485 data will utilize the same data
protocol and format as assigned to TxD1.
1.3 General Specifications
Operating Voltage: Model SSD120-(XX)A-RS
+12 to 30 VDC.
Model SSD120-(XX)AE-RS
2
+12 to 30 VDC.
Operating Current all models:
0.55 Amps. (550MA)
Operating Temperature:
Model SSD120-(XX)A-RS
-20
E
to +70
E
C.
Model SSD120-(XX)AE-RS -55
E
to +70
E
C.
Storage Temperature (non-operating) all models: -65
E
C to +85
E
C.
Warm-up time: 30 second self-test, see Figure 2.
Weight: 10 oz.
1
SSD120-(XX)AE-RS Extended operating temperature range: -55
E
C to +70
E
C.
2
Longer warm-up times will be experienced when operated at +12 VDC.
