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700 IR Series
INFRARED GAS DETECTOR FOR COMBUSTIBLE AND CO
GASES
USER MANUAL
3.4
Calibration Mode (AutoZero and AutoSpan)
3.4.1
AutoZero
The AutoZero function is used to set the detector's zero baseline. Local ambient air can be used
to zero calibrate the detector as long as it can be confirmed that it contains no combustible
hydrocarbon gases. If this cannot be confirmed then a zero air or pure N
used. With regards to CO
naturally CO
at a level of 0.03 to 0.04% vol..
2
Material Requirements:
• PN DET-327-000000-000 Programming Magnet
• PN DET-613-120000-700 OLCT 700/710 Series Splash Guard with integral Cal Port
and Calibration Wind Guard (PN DET-943-000000-000) -OR- PN DET-943-000006-
132 Threaded Calibration Adapter
• PN 18108010 Zero Air cal gas, or use ambient air if no combustible gas is present
• PN 18108007 Pure N
NOTE : The Calibration Wind Guard must be used when the Splashguard Adapter with integral
Cal Port is used. Failure to use the Calibration Wind Guard may result in an inaccurate AutoZero
calibration.
a) If the ambient air is known to contain no combustible hydrocarbon gas content, it can be used
to calibrate zero. If a zero air or N
calibration adapter and set flow rate of 0.5l/min and let detector purge for 1-2 minutes
before executing the AutoZero.
b) From Normal Operation, enter Calibration Mode by holding the programming magnet over
PGM1 for 3 seconds. Note, the "" prompt will show that the magnetic switch is activated
during the 3 second hold period. The display will then scroll "PGM1=Zero ...PGM2=Span".
Hold the programming magnet over PGM1 for 3 seconds once the "" prompt appears to
execute AutoZero (or allow to timeout in 5 seconds if AutoZero is not desired).
NOTE 1: Upon entering Calibration Mode, the 4-20mA signal drops to 2mA and is held at this
level until the program returns to normal operation. Modbus™ Status Register bit 14 is also set to
signify when the detector is in-calibration mode.
The OLCT 700/710 will display the following sequence of text messages as it proceeds through
the AutoZero sequence: Zero Cal. . .Setting Zero. . . Zero Saved.
c) Remove the zero gas and calibration adapter, if applicable.
20
gas detectors, it is mandatory to use pure N
2
cal gas for CO
gas detectors
2
2
gas cal cylinder is going to be used then attach the
2
2
cylinder should be
2
since ambient air contains
2
NP700IRIMEN
Revision E.0
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