Analytical Industries GPR-1500 A Series Trace PPM Oxygen Analyzer - Manual (Page 22)

Advanced Instruments, Inc
22
Range Selection
The GPR-1500-A transmitter is equipped with four (5) standard measuring ranges (see specification) and
provides users with a choice of sampling modes. By accessing the MAIN MENU, users may select either the
AUTO SAMPLING (ranging) or MANUAL SAMPLING (to lock on a single range) mode.
Note: For calibration purposes, use of the AUTO SAMPLE mode is recommended. For example, calibration
with ambient air (20.9% oxygen), the analyzer will automatically turn into 0-25% range. However, the user
can also select the MANUAL SAMPLE mode for calibration but the span gas must not exceed the full scale
of the manual range selected – for example, a span gas with an 80 PPM oxygen concentration in nitrogen
would dictate the use of the 0-100 PPM full scale range for calibration.
Auto Sampling
Access the MAIN MENU by pressing the MENU key.
Advance the reverse shade cursor using the ARROW keys to highlight AUTO SAMPLE.
Press the ENTER key to select the highlighted menu option.
The display returns to the sampling mode:
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATION
CONFIG ALARMS
BYPASS ALARMS
0.3 %
AUTO SAMPLING
1% RANGE
76 F 100 KPA
The display will shift to the next higher range when the oxygen reading exceeds 99.9% of the upper limit of
the current range. The display will shift to the next lower range when the oxygen reading drops to 85% of the
next lower range.
For example, if the transmitter is reading 1PPM on the 0-10 PPM range and an upset occurs, the display will
shift to the 0-100 PPM range when the oxygen reading exceeds 9.9 PPM. Conversely, once the upset
condition is corrected, the display will shift back to the 0-10 PPM range when the oxygen reading drops to
8.5 PPM.
Manual Sampling
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 display appears: