Teledyne Insta Trans - trace and percent oxygen transmitter - Manual (Page 27)

Trace Oxygen Transmitter Operation
Teledyne Analytical Instruments 19
Operation
4.1 Introduction
Once the transmitter has been installed, it must be configured to
your application. To do this you must:

Set the range.

Calibrate the instrument.
4.2 The Range and Calibration Functions
The transmitter is calibrated by using span gas.
Although the instrument can be spanned using air, a span gas with a
known oxygen concentration in the range of 70–90% of full scale of the
range of interest is recommended. Since the oxygen concentration in air
is 20.9% (209,000 ppm), the cell can take a long time to recover if the
instrument is used for trace oxygen analysis immediately following
calibration in air.
Connect the calibration gases to the transmitter according to the
instructions given in Section 3.3, Gas Connections, observing all the
prescribed precautions.
The gas supply should be off or set to a low flow before
connecting it to the transmitter, and be sure not to obstruct the
sample vent.
CAUTION: IN THE EVENT OF LOSS OF FLOW THROUGH THE
TRANSMITTER, IF THE VENT IS VENTED TO A
LOCATION OF HIGH OXYGEN CONTENT, OXYGEN
WILL BACK DIFFUSE THROUGH THE VENT LINE
AND IN MOST CASES QUICKLY SATURATE THE
CELL WITH OXYGEN WHICH CAN THEN REQUIRE A
LONG PURGE DOWN TIME FOR THE SENSOR
WHEN USED FOR LOW OXYGEN CONCENTRATION
MEASUREMENTS. IN THE EVENT THAT FLOW IS
INTERRUPTED INTO THE TRANSMITTER, IT IS