Line of Sight Infrared Hydrocarbon Gas Detector AutroPath HC800 , 116-P-HC800/IGB, Rev. A, 2016-03-03
P/N 95-8744, v4.2 , rev. 3/16
Autronica Fire and Security AS
Page 27
6. Verify the gain setting. The gas gain setting options
are 1, 2, 5, 10, 20, 50, and 100; ideal gain settings
are 2, 5, and 10.
A gain of 1 indicates that the system may be near
saturation (signal strength is too high). If the gas
gain number = 1 and the Active avg or Ref avg
numbers are greater than 1500, use the aperture
kit to reduce signal. See the “Transmitter Lamp
Voltage” section for additional signal strength
reduction options as needed. If using the Long
range receiver, it may be necessary to switch to
the Short range version.
A gain of 20 or greater indicates that the system
signal strength is less than expected. Ensure that
the system has a clear beam path, clean windows,
and was properly aligned and calibrated in clear
weather. See the Transmitter Lamp Voltage section
for additional signal strength increase options as
needed. If using the Short range receiver, it may
be necessary to switch to the Long range version.
Contact the factory for further information or assis-
tance.
In all cases, a green LED and 4 mA output indicate
that the unit will properly perform its safety func-
tion. Gain adjustments and checks are simply a
way to optimize the system so that it will perform
in the widest variety of application scenarios (e.g.,
shifting mounts, inclement weather, mechanical
impact, lens obscuration, etc.).
TRANSMITTER LAMP VOLTAGE
The AutroPath HC800 has a feature that automatically
adjusts transmitter lamp voltage during zero calibration
if the communication link is connected. (This feature is
disabled by default.) Alternatively, lamp voltage can be
adjusted via HART or Modbus communication directly
to the transmitter. The transmitter lamp voltage should
be lowered to reduce signal at the receiver. Transmitter
lamp voltage should be raised to increase signal at the
Receiver. The adjustment range for the transmitter lamp
is 400-950 V (default = 750 V). Contact the factory for
further information or assistance.
calibRation
CALIBRATION OVERVIEW
Span calibration is not required. The AutroPath HC800
supports non-intrusive field zero calibration, although
routine calibration is normally not required.
ZERO CALIBRATION
Zero Calibration is a one-step process consisting of clean
air (zero) condition adjustment only, which is performed
automatically by the device. This procedure adjusts the
“clean air” signal output only, and is normally used if the
gas output signal level has drifted. The cause of drift is
typically due to the presence of background gas during
calibration. Additionally, the zero calibration procedure
will optimize the transmitter lamp output intensity if the
optional communication link is installed. This is useful for
situations where the signal strength at the receiver is too
large (saturation) or too small. Ensure that the optical path
is clear of hydrocarbons prior to calibration initiation to
ensure an accurate zero (clean air) condition.
IMPORTANT CALIBRATION NOTES
NOTE
Ensure that the detector has been operating for at
least two hours before calibrating.
NOTE
Always ensure that the AutroPath HC800 optics
are totally free of all hydrocarbons before initiating
calibration.
NOTE
Zero calibration cannot be performed if the detector
is improperly aligned. When correct alignment is
achieved, the sensor ratio (active vs. reference
signals) should be between 0.8 and 1.3. To check
the ratio, connect a HART handheld and navigate to:
Main > Detector Status > Sensor Info > Ratio
An out-of-tolerance ratio value typically indicates
incorrect alignment or presence of background gas.
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