Operating Manual PG11 / PGE11 Page 29
6.3 Keeping a stable Zeroing of the Detector
6.3.1 The OptoBAS™ function
The OptoBAS™ function of PG11 is keeping the Maintenance requirements of the detector to a minimum by
taking away the need to do manual zeroing of the detector. This will make sure the detector will show zero
gas value when there is no gas present. The OptoBAS™ function will make minor adjustments to the zero
level over a long period of time keep the Detector stable. If there is any gas present the OptoBAS™ will not
perform any adjustments.
6.3.2 Manual zero adjustment
Warning! This procedure should only be performed by trained Operators. If this is not done in a proper way,
the performance of the detector can be jeopardized.
Normally this is not needed, but for some special applications this might be useful. For example if the
detector is used in an application requiring the OptoBAS be deactivated due to a low background level of
gas present at all times. Also the OptoBAS™ has a limited range it will handle and a Manual zeroing of the
Detector might in some cases be needed.
Requirements:
• Gas Sampling kit
• Nitrogen or clean air
• The Detector shall prior to starting the procedure below be powered up for at least 20 minutes in a
stable environment between 15 - 30°C.
Procedure:
1. Clean the Detector optics, both mirror and lens.
2. Connect to the detector through
HART®
or
Modbus RTU
as described in those chapters
3. Connect the tube from the Gas cylinder to one of the nozzles on the Gas Sampling kit
4. Fit the Gas Sampling kit as illustrated in “Performing a Calibration check”.
5. Apply the nitrogen or clean air at a flow rate above 0.3 liters/min
6. Wait for 1-2 minutes until the reading stabilizes
7. Start Zeroing from the HART interface.
8. Wait for confirmation.
6.4 Self Diagnostics
All Safety critical electronic components are monitored and stored in the Diagnostics log if outside
specification. In addition vibration, temperature and optical signals are analysed and stored in the Diagnostics
log. The Diagnostics log is downloaded at the vendor during any Service or inspection of the Detector. The
Diagnostics log can also be downloaded by the user and sent to the vendor for analysis and troubleshooting.
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