System 3 - YOKOGAWA ZR402G User Manual

1.1.3

System 3

This example, System 3, represents typical applications in large boilers and heating furnaces,
where 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 ZR20H 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
sensor.
Automatic calibration unit
ZR20H
Note:
The installation temperature limits range for integrated type analyzer is -20 to 55°C.
1 Shield cable:
*
Use shielded signal cables, and connect the shields 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
Use approx. 1 vol% O
Figure1.3
*2
ZR202G Integrated type Zirconia Oxygen/Humidity Analyzer
with automatic calibration unit (ZR202G-
~
Reference gas
Span gas
Calibration gas (Zero)
gas (N -based).
2 2
Example of System 3
*1
100 to 240 V AC
Contact input
Analog output, contact output
Digital output (HART)
Air Set
Instrument air
Calibration
gas pressure
regulator
Zero gas cylinder
*3
Calibration gas unit case
gas cannot be used as the zero gas.
2
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IM 11M12A01-04E 11th Edition : Jul. 19, 2017-00
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