System 3 - YOKOGAWA ZR22G User Manual

1.1.3

System 3

This example, System 3, represents typical applications in large boilers and heating furnaces,
where there is a need to monitor and control oxygen concentration. The reference gas and
calibration-time span gas are (clean, dry) instrument air. Zero gas is supplied from a gas cylinder.
System 3 uses the ZR40H automatic calibration unit, with auto-switching of the calibration gas.
A "combustible gas detected" contact input turns off power to the heater. There's also contact
output from the converter that can be used to operate a purge gas valve to supply air to the
detector.
ZR22G Separate type
Zirconia Oxygen/Humidity Analyzer, Detector
Check valve
*1 Shield cable ; Use shielded signal cables, and connect the shield to the FG terminal of the converter.
*2 Select the desired probe from the Probe Configuration table on page 1-4.
*3 When a zirconia oxygen analyzer is used, 100% N
based).
Figure1.3
*2
*1
Signal
(6-core shield cable)
Heater (2-core)
Flowmeter
Reference gas
Calibration gas
Automatic Calibration Unit
System 2
ZR802G Converter
~ 100 to 240 V AC
Needle
valve
Air Set
Pressure
ZR40H
reducing
valve
*3
Calibration gas
unit case
gas cannot be used as the zero gas. Use approximately 1% of O
2
<1. Overview>
Contact input
Analog output, contact output
Digital output (HART)
lnstrument air
Zero gas cylinder
F1-3E.ai
IM 11M12G01-02EN 1sh Edition : Mar. 25, 2021-00
1-3
gas (N -
2 2