COSA Xentaur COSA 9610 - Manual (Page 8)

INSTALLATION, OPERATION AND MAINTENANCE MANUAL – COSA 9610™
Page 8 of 44
1.3. C
ALIBRATION
P
ROCEDURE
The analyzer can be calibrated in three different ways:
•
Single point calibration
Only one calibration gas is used. The value of the gas is chosen middle of the
measuring range. This is only used to correct any offset error to the measurements.
•
Two point calibration
Two calibration gases are used. The low calibration gas is set at ± 20% of the
measuring range. The high calibration gas is set at ± 80% of the measuring range.
The advantage over a single point calibration is the increased accuracy over the entire
span.
•
Three point calibration
This method uses three calibration gases and is mandatory for a dual range analyzer.
The medium range calibration gas must be in the middle of the measuring range.
All three calibration methods can be performed both manually and automatically:
•
Manually
The operator navigates the procedure via on-screen menu to open the correct gas
valves to the analyzer. The operator controls the timing.
•
Automatically
The analyzer itself controls the timing of the valves switching. When the measured
values stay within the specified tolerances, the newly calculated calibration
parameters will be accepted. Otherwise, the analyzer will keep the old value and
generates a CAL ERROR on the display and switch the system fault contact and
calibration fault contact.
The automatic calibration can be started as followed:
•
Programmable time schedule (Timed calibration)
•
Initiated manually via on-screen menu (Semi-automatic calibration)
•
External host activates the calibration request contact (Remote calibration)
The one-point calibration/validation procedure will be executed as followed:
1. Analyzer activates calibration/validation contact.
2. The procedure pauses for the specified “Calibration Start Delay” time for the
external host to prepare for calibration/validation.
3. Process gas is switched off and the calibration gas is switch on.
4. The analyzer waits for the readings to stabilize up to the “Switch Time”.
5. Calibration gas is switched off and the process gas is switched on.
6. Analyzer deactivates calibration/validation contact.