System 3 - YOKOGAWA EXAxtZR Instruction Manual

1.1.3

System 3

Model ZR22G Separate type Zirconia OxygenAnalyzer
Detector
IM 11M12A01-02E
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 autocalibration 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 sensor.
*2
Signal
(6-core shield cable)
Check valve
Heater (2-core)
Reference gas
Calibration gas
Model ZR40H Aoto-Calibration unit
*1 Shield cable;
Use shielded signal cables, and connect the shield to the FG terminal of the con-
verter.
*2 Select the desired probe from the Probe Configuration table on page 1-4.
*3 When a zirconia oxygen analyzer is used, 100% N
gas. Use approximately 1% of O
Figure1.3
EXA ZR402G
*1
Flowmeter Needle
vaive
*3
gas (N2-based).
2
Model ZR402G Converter
100 to 240 V AC
Contact input
Analog output, contact output
Digital output (HART)
Air Set
lnstrument air
Calibration gas pressure regulator
Calibration gas
unit case
Zero gas cylinder
gas cannot be used as the zero
2
1. Overview
F1.3E.EPS
1-3