Teledyne Analytical Instruments 311PC, Instruction Manual

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Percent Oxygen Analyzer Operation 3
3–3
Teledyne Analytical Instruments
If this should occur, a partial vacuum would be drawn on the cell.
Since the cell is a partial pressure sensitive device, any oxygen readings
taken under these conditions would be erroneous. Pressure less than 0.3
atm. could damage the cell.
Caution: If the meter reads in the orange portion of the scale while on the
0–25% oxygen scale after being calibrated, turn off the instru-
ment and disconnect the source fitting followed by the vent
fitting. This instrument is not approved for service in oxygen
rich (oxygen concentration greater than 21%) environments.
3.5 Calibration
The inherently constant output of the cell during its useful life elimi-
nates the need for frequent calibration. TAI feels that the interval between
calibrations should be dictated by the customer’s application.
The Model 311PC should be calibrated using a span gas with a known
oxygen concentration. Ambient air (20.9% ) is recommended for calibra-
tion.
The analyzer can be calibrated on any range using a span gas. The span
gas concentration should be within 70% to 90% of full scale of the range
selected.
Note: Using a span gas with a concentration greater than 100% of full
scale will put you in the next range and result in a reduced accu-
racy.
3.4.1 Calibration Procedure Using Air
To calibrate the instrument with atmospheric air as a standard, use the
following procedure:
1) Stand the instrument upright on a level surface, and with the
range switch in the “OFF” position, check the alignment of the
meter pointer with the zero mark on the scale. Use the mirror to
eliminate parallax, and adjust the screw on the face of the meter,
if necessary, until the pointer and zero mark are in precise
coincidence.
2) Advance the range switch to the 0–25% position.