3-3
Teledyne Analytical Instruments
Percent Oxygen Transmitter Operation 3
3.2.2 Setting the Span Potentiometer (P1) using AIR
7. Set switch SW-1 to position “B” (AIR CAL) and flow air
through the system. This can be done by either disconnecting the
sample line and allowing air to flow or inserting a tee with
appropriate valves to allow switching between sample and air
without having to disconnect the sample in line.
8. After the reading was stabilized, set P1 to read a stable
20.00 +/- 0.01 mA output.
9. Return switch SW-1 to the operating position “A”.
3.2.3 Setting the Span Potentiometer (P1) using SPAN GAS
8. Set switch SW-1 to the normal operating position “A”. Flow a
span gas through the system and allow time for stabilization.
NOTE: The span gas should have an O
2
concentration of 80% -
100% of full scale. For example, if you have a 0-10%
transmitter, the span gas should be a certified grade gas of about
9% O
2
in N
2
or Argon.
9. Adjust span potentiometer P1 to read an output current
determined by the following equation:
Span Gas Concentration in %
Full Scale Concentration in %
mA = Output in mA
+
4
10. Remove meter and reconnect incoming wire to Terminal 2.
Replace junction box cover and close transmitter box door.
3.3 Operating the OxygenTransmetter
1. After calibrating the instrument, reconnect the sample in line if it
was disconnected.
2. Open the transmitter door and set switch SW-1 back to position
"A" if this has not already been done.
CAUTION: The 0–25% oxygen analysis range can be used to accurately
measure the oxygen concentration in a gas mixture containing up
to 24% Oxygen. Oxygen concentrations above 24% under extreme
conditions can cause the instrument to produce unreliable read-
ings on the 0–25% oxygen scale. Use this range for gas mixtures
containing 0–24% oxygen only.
