Maintenance
the calibration cap. For details about how to use a calibration
cap, see Calibration Cap on page 32.
c) Apply fresh air to the detector, and wait for a few minutes until
the reading is stable.
d) Using the UP and DOWN buttons, adjust the output voltage so
that the voltmeter is reading slightly above zero, and then
decrease the reading slowly so that it reads zero.
e) When the output voltage is adjusted close to zero, accept the
zero calibration by holding UP button for 2 seconds.
4. If a span calibration is required, after successful zero calibration it
will move to span calibration automatically. If a span calibration is
not required, exit from calibration by holding DOWN button for 5
seconds. This will cancel a span calibration while zero calibration
result sustains.
a) Move to the next step by holding the UP button for 2 seconds.
b) Connect a cylinder of span gas to the detector. Where the
greatest accuracy is required, the cylinder concentration should
be usually around the alarm set point or 50% of the range of the
detector.
c) Apply the span gas to the detector, and wait for a few minutes
until the reading is stable.
d) Using the UP and DOWN buttons, adjust the output voltage
until it reaches the target value. Use the formula below to
calculate what the correct voltage should be.
V
out
= Gas concentration ÷ detector range
For example, if you are applying 45% LEL gas with a 100% LEL
detector range, you would need to adjust the voltage output so
that the reading on the voltmeter shows:
45 ÷ 100 = 0.45 V
e) When the output voltage is adjusted close to target gas
concentration, accept the span calibration by holding UP button
for 2 seconds.
5. Purge the gas sensor.
a) Move to the next step by holding the UP button for 2 seconds.
b) Remove the span gas from the detector.
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