AFR200 Series, Product User Guide
This document is subject to change without notice.
Caution: None of GAC products are flight certified controls including this item
Copyright © 2010, Governors America Corp., All Rights Reserved
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PUG4144 D
3.6.4 Exhaust Gas Temperature (EGT) Sensor
The AFR has the ability to monitor a type K thermocouple to determine engine exhaust gas temperature. If the
high temperature threshold is exceeded during operation, the AFR will impose a de-rate in throttle % and will
allow the system to recover once the temperature has returned to the normal operating region. If the temperature
does not decrease over a set time interval the AFR will shut the engine down. These limits and thresholds can be
calibrated within the AFR controller using SmartVU.
3.7 Binary Inputs / Outputs
The following section covers the various low-side (close to ground) outputs and inputs the AFR includes.
3.7.1 Power Relay Output
The AFR includes a 2A low-side binary output for control of the power relay. The power relay is used to provide
power to the oxygen sensor heaters as well as control the shutdown of the engine. This information is detailed
greater in following sections.
3.7.2 Malfunction Indicator Lamp (MIL) Output
The AFR provides an optional Malfunction Indicator Lamp (MIL) output which can be wired to an external fault
lamp or buzzer in order to indicate engine, sensor, or controller malfunctions. This output is triggered to match
the Fault LED on the AFR itself. The max current is 2A and the output is a 12V or 24V high side output. The
blink patterns and fault indication is covered in greater detail in the diagnostics section.
3.7.3 Engine Speed Increment / Decrement
The AFR has two active low binary inputs used to control variable speed increment and decrement. When tied to
ground momentarily each of these inputs will either increment or decrement engine speed by 10 RPM while in
variable speed mode.
Take extreme caution when using this feature since it will allow adjustment through the full range of engine RPM
up to the overspeed setpoint if the limits have not been calibrated.
