Analytical Industries GPR-2500 S Oxygen Analyzer - Manual (Page 24)

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MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATE
24.5 C 100 KPA
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CALIBRATION
SPAN CALIBRATE
ZERO CALIBRATE
DEFAULT SPAN
DEFAULT ZERO
24.5 C 100 KPA
Span Calibration
Maximum drift from calibration temperature is approximately 0.11% of reading per °C. The monitor has been
calibrated at the factory. However, in order to obtain reliable data, the monitor must be calibrated at the initial
start-up and periodically thereafter. The maximum calibration interval recommended is approximately 3 months, or
as determined by the user’s application.
Calibration involves adjusting the monitor electronics to the sensor’s signal output at a given oxygen standard, e.g.
a certified span gas with an oxygen content (balance nitrogen) approximating 80% of the next higher full scale
range above the intended measuring range is recommended for optimum accuracy, see Calibration and Accuracy.
Calibration with ambient or instrument air (20.9% or 209,000 ppm) is recommended when installing a new sensor
or when a certified gas is not available.
Ambient Monitor GPR-2500S: When configured for ambient monitoring of oxygen deficiency in a confined
space or room do not calibrate the unit in the atmosphere to be monitored. Use a certified span gas of a known
oxygen concentration approximating 20.9% oxygen balance nitrogen or clean compressed air. Refer to the
illustration below and locate Item #5 to identify the Flow Through Adapter used to calibrate a GPR-2500 configured
for ambient monitoring or equipped with a remotely located sensor. The user is responsible for supplying an
adequate amount of Tygon tubing to pipe the span gas to the adaptor.
General Service:
In standard configuration, the GPR-2500 can be calibrated by exposing the sensor to the readily available cost
effective and reliable 20.9% (209,000 ppm) oxygen concentration of ordinary atmospheric air or a certified span
gas with an oxygen concentration of 80-100% of full scale range balance nitrogen. For example, for a 0-25%
range, the span gas should be a certified grade between 19-23% oxygen preferably approximately 20.9% oxygen.
Caution: Regardless of configuration to assure proper grounding, connect the 4-20mA signal output to the external
device (PLC, DCS, etc.) before attempting any zero or span adjustments.
Factory Default Span
The software will set the SPAN adjustment based on the average oxygen reading (actually the sensor’s signal
output) at a specified oxygen concentration. For example, when a span gas is introduced, the micro-processor will
display an oxygen reading within +50% of the span gas value. This feature allows the user to test the sensor’s
signal output without removing it from the sensor housing.
Access the MAIN MENU by pressing the MENU key.
Advance the reverse shade cursor using the ARROW keys to highlight MANUAL SAMPLE.
Press the ENTER key to select the highlighted menu option.
The following displays appears: