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3
Operation
Diagnostic Procedures
E
Simple Zero Test
This test will ensure the unit is calibrated for a true
"zero" and duly represents an absence of target gas
in this condition.
Start: Set meter to mV DC, place meter leads on
Test(+) and Test(—) respectively (see Figure 9).
•
Apply pure nitrogen (N
at a rate of .6 Liter/min. for at least 3 minutes.
Check the status of the yellow "system" LED.
If this LED is continuous ON, place the unit in
non-filtered output run mode by pressing both
the "zero" (S1) and "span" (S2) buttons
simultaneously for 1 second or until the "system"
LED begins to blink slowly. See example below.
•
Wait until output signal has stabilized to within
± .02 mA of signal deviation/change.
•
Output should read between 3.9 and 4.1 mA
(39.0 to 41.0 mV).
If this is not the case, proceed to the next step.
•
Follow the "zero" procedure above to re-zero
the unit
•
Follow the "simple zero test" procedure to
ensure the unit is resting at the optimum 4 mA
point.
Simple "Zero" test — NO "Dead-band" mode 0 to 26 mA
LED
SEQUENCE
G
POWER
SYSTEM
Y
CALIBRATE
Y
FAULT
R
mA FAULT
R
G
SOURCE
G
ATMOS
Manning AirScan-iR Refrigerant Sensor
continued
) into the calibration port
2
OFF
OFF
OFF
N/A
19100 AirScan-iR-ind 05/2006 REVA Copyright © 2006 Manning Systems, Inc. All Rights Reserved.
Exit: Press and hold both the "zero" (S1) and "span"
(S2) buttons simultaneously for 1 second or more
until "system" LED is continuous ON. Unit should be
ready for long-term operation.
4/20 mA Output Loop Integrity Check
22 mA High Signal Test
STEP 1
Start: Set meter to mV DC, place meter leads on
Test(+) and Test(—) respectively (see Figure 9).
•
Press the "zero" (S1) button 5 times. The yellow
"calibrate" LED will blink fast and the yellow
"system" LED will turn off. The output should be
21 to 22.5 mA (210 to 225 mV).
If a problem exists on the output signal line, or the
output load is not within the specified range, the "mA
fault" LED will blink either before or upon activation of
this test. In some cases the 22 mA high signal output
will cause incorrect output load resistance values to
surface because of the demand on high resistances
to produce high currents.
Low power supply voltages can also be something to
investigate if this error surfaces only when the 22 mA
high test is initiated.
During 4/20 mA loop test (22 mA high)
LED
SEQUENCE
POWER
G
Y
OFF
SYSTEM
Y
CALIBRATE
N/A
FAULT
R
mA FAULT
R
N/A
SOURCE
G
N/A
G
N/A
ATMOS
19
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