Analytical Industries GPR-1200 ATEX Portable Trace PPM Oxygen Analyzer User Manual
Page 10
10
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 LED.
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 trace oxygen measurements, the sensor is exposed to sample gas that must flow or be drawn through the analyzer’s
internal sample system. This unique sample system, when operated accordingly 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:
¾ 1/8” tube fittings for the inlet and outlet
¾ flow control metering valve
¾ 4-way sample/bypass valve to purge lines and isolate the sensor
¾ Stainless steel sensor housing with an o-ring seal to prevent the leakage of air
¾ Flow indicator common to bypass and sample lines
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