Teledyne 311 - Portable trace oxygen analyzer - Manual (Page 10)

3.2.2 Standard (Span) Gas Calibration (optional)
Gas
required:
- Zero gas
- (70-90%) of full scale of the primary (working) range
NOTE: If the primary (working) range is a lower range, when
you change to a higher range recalibration is a must for
accuracy (see Figure 2 Chart, included).
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 screw on the face of the
meter, if necessary, until the pointer and zero mark is in precise coincidence.
2. Install a sensor.
3. Install quick disconnect, FIRST TO THE VENT then the sample inlet.
4. Purge the analyzer with a zero gas for 12-16 hours at 2 SCFH.
5. Advance the range to CAL.
6. Connect span gas.
7. Advance the range when oxygen level is decreasing, wait until the reading
stabilizes.
8. Unlock and adjust span control until the meter reads the oxygen content.
9. Advance the range to CAL.
10. Disconnect the span gas.
11. Connect the sample gas.
12. Advance the range when the oxygen level is decreasing, so that the meter gives
the best possible resolution of the oxygen. DO NOT attempt to take a reading until the meter
indicator stabilizes.
3.3 Positive Pressure Sampling. When connecting the instrument to a positive
pressure sample source, ALWAYS proceed as follows:
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