Garmin GDU 370 Installation Manual page 141

A.3.6.2 Discrete Outputs
INACTIVE: Floating (can be pulled up to externally sourced Vout in the range 0 ≤  V out ≤  3 3VDC)
Leakage current in the INACTIVE state is typically ≤ 10 uA to ground
ACTIVE: Vout ≤ 0.5VDC with ≤  2 0 mA sink current
Sink current must be externally limited to 20 mA max
Pin Connector
13 P731
14 P731
* Indicates Active Low
A.3.7 Analog Input Configuration
Some analog inputs are multi-purpose capable and have several configuration options. These inputs are
configured automatically at power on by a configuration file stored in the GDU. The following table
summarizes the configuration options.
Configurable Parameter
Resistive Divider
Voltage Measurement Ranges
Bipolar/Unipolar
Constant Current Source
Miscellaneous Sensor
Configuration Parameters
G3X Installation Manual – Pinouts
190-01115-01
Pin Name
DISCRETE OUT* 1
DISCRETE OUT* 2
Description/Characteristic
Resistive Divider can be enabled or disabled for Analog Input
channels 14-25. Enabling & Disabling is achieved via software
configuration.
When Disabled: Hardware scaling is 1:1 and input impedance is
greater than 10 MΩ.
When Enabled: Hardware scaling is approximately 45:1 and input
impedance is approximately 100 kΩ.
There are six voltage measurement ranges for analog inputs:
•
25 mV, 55 mV, 100 mV, 1.0 Vdc, 2.5 Vdc, and 5.0 Vdc
(Applies to both 1:1 and 45:1 scaling).
Effective voltage range in 45:1 mode:
•
1.125 Vdc, 2.475 Vdc, 4.5 Vdc, and 45 Vdc.
Each analog input can be configured to measure Bi-Polar (positive
and negative) or Uni-Polar (positive only) voltages. All analog inputs
are differential.
Analog Input channels 12, 13, 22, 23, 24, & 25 can be configured to
supply a 250 µA constant current source (CCS) from the positive
differential input used to measure resistive sensors. The negative
(LO) side of a CCS configured input must be tied to unit ground to
provide a current path to ground.
•
Update Rate
•
Voltage Translation Equations
•
Minimum/Maximum Values for Sensors
•
Hysteresis Value
•
Digital Filtering Value
I/O
OUT
OUT
Page A-13
Revision A