Teledyne 3020M - Explosion proof paramagnetic oxygen analyzer - Manual (Page 17)

2-3
Percent Paramagnetic Oxygen Analyzer Operational Theory 2
Teledyne Analytical Instruments
Pin out:
1 -15Vdc test pin (Not connected)
2 +15Vdc test pin (Not connected)
3 Measuring ground
4 Not used
5 Preamplifier output ~0- 1 Vdc
6 Not used
7 24 Vdc return, power ground
8 Collector of transistor switching heating element (Not con-
nected)
9 Fault signal: <0 Vdc= OK, >4.6 Vdc = Fault (Not connected)
1 0 Not used
1 1 Negative reference voltage (Not connected)
1 2 Positive reference voltage (Not connected)
1 3 Nominal temperature voltage signal (Not connected)
1 4 Actual temperature voltage signal (Not connected)
1 5 +24 Vdc power.
2.3 Cross Interference
As mentioned previously, the selectivity of the measuring system is
based on the extraordinarily high magnetic susceptibility of Oxygen com-
pared to other gases. In most cases the presence of other gases can be ig-
nored but significant errors can occur when the sensor is calibrated with a
mixture of oxygen and nitrogen and the sample gas consists mainly of other
gases with considerable magnetic susceptibility. In this case, the reading
shows a measured value even if the sample gas contains no Oxygen. It is
actually displaying the cross sensitivity to another gas.
The following table shows the cross sensitivity of some gases when
changing from pure nitrogen to 100% of one of the gases listed.
Sensor
(rear view shown)