Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 114)

IM 11M13A01-04E 9-6
9.2.1.4 Span-gas Concentration
Set the oxygen concentration for span calibration. If instrument air is used as the span
gas, enter 21 %O
2
.
When using the ZO21S Standard Gas Unit (for use of the atmospheric air as a span gas),
use a hand-held oxygen analyzer to measure the actual oxygen concentration, and then
enter it.
CAUTION
(1) When instrument air is used for the span calibration, remove the moisture from the
instrument air at a dew-point temperature of -20˚C and also remove any oily mist
and dust from that air.
(2) If dehumidifying is not enough, or if foul air is used, the measurement accuracy will
be adversely affected.
9.2.1.5 Calibration Time
• When the calibration mode is in manual:
First set the output stabilization time. This indicates the time required from the end of
calibration to entering a measurement again. This time, after calibration, the measure-
ment gas enters the sensor to set the time until the output returns to normal. The
output remains held after completing the calibration operation until the output
stabilization time elapses. The calibration time set ranges from 00 minutes, 00
seconds to 60 minutes, 59 seconds. For more details, consult Section 8.3,”Setting
Output Hold.” When the calibration mode is in semi-automatic, set the output
stabilization time and calibration time. The calibration time is the time required from
starting the flow of the calibration gas to reading out the measured value. The set
calibration time is effective in conducting both zero and span calibrations. The
calibration-time set ranges from 00 minutes, 00 seconds to 60 minutes, 59 seconds.
Figure 9.4 shows the relationship between the calibration time and output stabilization
time.
Analog output remains hold
(when output remains hold)
Calibration start
(contact or switch input)
Span calibration
(span-gas valve open)
Zero-point calibration
(zero-gas valve open)
Analog output status
Calibration time
Calibration time
Stabilization
time
F9.4E.EPS
Figure 9.4 Calibration and Output-stabilization Time Settings