190-00207-02 GTX 330/330D Installation Manual
Rev. U Page 4-3
4.2 Power and Lighting Function
Power Input requirements and Lighting Bus input are listed in the following tables. The power-input pins
accept 14/28 Vdc. AIRCRAFT POWER 2 is for connecting to an alternate power source, such as on
aircraft with two electrical buses. Switched Power Out is a power source available for devices such as a
remote digital altitude encoder. Refer to
Figure D-1 and Figure D-2 for power and lighting
interconnections.
4.2.1 Aircraft Power
4.2.2 Lighting Bus
The GTX 330 unit can be configured to track a 28 Vdc, 14 Vdc, 5 Vdc or 5 Vac lighting bus using these
inputs. The GTX 330 can also automatically adjust for ambient lighting conditions based on the photocell.
Refer to Section 5.2.5 and Section 5.2.6 for lighting configuration.
4.3 Temperature Inputs
Temperature input is used for Outside Air Temperature (OAT) display and Density Altitude computations.
The type of temperature probe required is a current sensor type, such as an EDMO P/N 655-PROBE or
Davtron P/N C307PS. Connect the red wire to pin 41 and the black wire to pin 44. The GTX 330 is not
configurable for different types of temperature sensors. The temperature-input specification is 1 microamp
per degree Kelvin (1 μA/°K). Refer to
Figure D-6 for the temperature probe interconnect and to Section
5.2.12 for probe configuration.
Table 4-2 Aircraft Power Pin Assignments
Pin Name Pin Number I/O
AIRCRAFT POWER 1 21 In
AIRCRAFT POWER 1 42 In
AIRCRAFT POWER 2 56 In
AIRCRAFT POWER 2 60 In
SWITCHED POWER OUT 62 Out
POWER GROUND 27 --
POWER GROUND 43 --
Table 4-3 Aircraft Lighting Pin Assignments
Pin Name Pin Number I/O
14 V/5 V LIGHTING BUS HI 45 In
28 V LIGHTING BUS HI 14 In
Table 4-4 Temperature Probe Pin Assignments
Pin Name Pin Number I/O
CURRENT TEMPERATURE PROBE OUT 41 Out
CURRENT TEMPERATURE PROBE IN 44 In