Advanced Instruments Inc.
Electronics
The signal generated by the sensor is processed by state of the art low power micro-processor based digital circuitry.
The first stage amplifies the signal. The second stage eliminates the low frequency noise. The third stage employs a
high frequency filter and compensates for signal output variations caused by ambient temperature changes. The result
is a very stable signal. Sample oxygen is analyzed very accurately. Response time of 90% of full scale is less than 10
seconds (actual experience may vary due to the integrity of sample line connections, dead volume and flow rate
selected) on all ranges under ambient monitoring conditions. Sensitivity is typically 0.5% of full scale low range.
Oxygen readings may be recorded by an external device via the 0-1V signal output jack.
Power is supplied by an integral rechargeable lead acid battery which provides enough power to operate the analyzer
continuously for approximately 60 days. An LED located on the front panel provides a blinking 72 hour warning to
recharge the battery. A 9VAC adapter (positive pole located on the inside of the female connector) can be used to
recharge the battery from a 110V or 220V convenience outlet. The analyzer is designed to be fully operational during
the 8-10 hour charging cycle which is indicated by a second continuously lit CHARGE LED (only when the analyzer
power is turned ON).
Sample System
The GPR-1200 is supplied with a unique bypass sample system which enables the user to isolate the sensor from
exposure to high oxygen concentration which results in a substantial increase is user productivity. However the sample
must be properly presented to the sensor to ensure an accurate measurement.
For PPM oxygen measurements, the sensor is exposed to the sample gas that must flow or be drawn through the
analyzer’s internal sample system. This unique sample system, when operated according to the instructions in this
Owner’s Manual, can significantly increase user productivity by minimizing the sensor’s exposure to ambient air or high
oxygen concentrations which contribute to the significant amount of downtime associated with competitive analyzers.
As illustrated above, the GPR-1200’s internal sample system includes:
1/8” tube fittings for the inlet and outlet
Flow control metering valve
A 4-way sample/bypass valve to purge lines and isolate the sensor
Stainless steel sensor housing with an o-ring seal to prevent the leakage of air
Flow indicator common to bypass and sample lines
Optional sample pump to draw sample through the analyzer (not shown in the above flow schematic).
Users interested in adding their own sample conditioning system should consult the factory. Advanced Instruments Inc.
offers a full line of sample handling, conditioning and expertise to meet your application requirements. Contact us at
909-392-6900 or e-mail us at
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