Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 16)

<1. Overview>
1-2
IM 11M12A01-02E 8th Edition : Jan.13,2012-00
NOTE
• As this system uses ambient air for the reference gas, measuring accuracy will be affected
by the installation location.
• A needle (stop) valve should be connected to the calibration gas inlet of the detector.
The valve should be fully closed unless calibration is in progress.
1.1.2 System 2
This system is for monitoring and controlling oxygen concentration in the combustion gases of a
large-size boiler or heating furnace. Clean (dry) air (21 vol% O
2
) is used as the reference gas and
the span gas for calibration. Zero gas is fed in from a cylinder during calibration. The gas flow is
controlled by the ZA8F flow setting unit (for manual valve operation).
F1-2E.ai
ZR402G Converter
Check valve
or Stop Valve
ZA8F Flow Setting Unit
EXA ZR402G
ZR22G Separate type
Zirconia Oxygen Analyzer, Detector
100 to
240 V AC
Air Set
Instrument air Calibration gas
Reference
gas
Flowmeter
Needle
valve
Calibration gas
unit case
Zero gas
cylinder
Span gas
(Same as Zero gas calibration unit)
Contact input
Analog output, contact output
(Digital output HART)
Signal
(6-core shield cable)
Heater(2-core)
~
Pressure
reducing
valve
Figure1.2