Analytical Industries GPR-1600 MS Series PPB Oxygen Analyzer - Manual (Page 29)

Advanced Instruments Inc.
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4. Press the ENTER key to bypass and disable both the local audible alarm and relay contacts. After 3 seconds, the system
returns to SAMPLING mode.
Note: The appropriate alarm setting will alternately reverse shades indicating the alarm condition exists but the BYPASS
ALARMS feature has disabled the local audible alarm and relay contact. The alarms are enabled when the alarm condition is
corrected.
3.3
PPM
AUTO SAMPLING
10 PPM RANGE
24.5 C
LO1 2 PPM 10 PPM HI2
Installation & Start-up is now complete . . . proceed to Calibration
Zero Calibration
In theory, the galvanic fuel cell type oxygen has an absolute zero meaning it produces no signal output when exposed to an
oxygen free sample gas. In reality, expect the analyzer to generate an oxygen reading when sampling a zero gas due to:
¾ Contamination or quality of the zero gas
¾ Minor leakage in the sample line connections
¾ Residual oxygen dissolved in the sensor’s electrolyte
¾ Tolerances of the electronic components
The Zero Offset capability of the analyzer is limited to 50% of lowest most sensitive range available with the analyzer.
As part of our Quality Control Certification process, the zero capability of every ppm analyzer is qualified prior to shipment.
However, because the factory sample system conditions differ from that of the user, no ZERO OFFSET adjustment is made to
analyzer by the factory
Recommendations:
¾ ZERO CALIBRATION is recommended only for online analyzers performing continuous analysis below 5% of the lowest
most sensitive range available with a ppm analyzer, e.g. analysis below 0.05 ppm on the 0-1 ppm range, 0.5 ppm on the
10 ppm range, or below 0.1% (1000 ppm) with a percent analyzer.
¾ Determining the true ZERO CALIBRATION adjustment requires approximately 24 hours to assure the galvanic fuel cell
sensor has consumed the oxygen that has dissolved into the electrolyte inside the sensor while exposed to air or
percentage levels of oxygen. After allowing the analyzer to stabilize with flowing zero gas (evidenced by a stable reading or
horizontal trend on an external recording device) perform the DEFAULT ZERO function before the ZERO CALIBRATION
function. For optimum accuracy, utilize as much of the actual sample system as possible.
¾ Always calibrate at the same temperature and pressure of the sample gas stream.
¾ Caution: Prematurely initiating the ZERO CALIBRATION function can result in negative readings near zero.
¾ ZERO CALIBRATION should precede SPAN CALIBRATION.
¾ If a ZERO CALIBRATION adjustment is made during initial installation, it is normally not required again until the sample
system connections are modified or a new oxygen sensor is installed. Therefore the DEFAULT ZERO function is