2
1.3
System Hardware – Fig. 1.2
The EXGP Oxygen Probe is an 'in situ' method of measuring
oxygen concentration designed for use in hazardous areas
(Zone 1). When used in conjunction with the EXGP Interface
Electronics Unit (also Zone 1 Certified), it enables signals to be
retransmitted up to 1km into a safe area.
The oxygen probe provides a mV signal that relates directly to
oxygen concentration in the range 0.25 to 25% O
2
, over a
process temperature range of 600
°
C to 1250
°
C. An integral 'R'
type thermocouple provides accurate continuous
measurement of the process temperature.
A calibration gas inlet port is provided to enable the probe to be
checked using test gas mixtures without removing it from the
process.
Reference air supplied at a rate of 100 to 1000cm
3
/hr (0.2 to
2ft
3
/hr) is required for accurate operation and can be provided
by a pump or regulator unit – see Fig. 1.2.
…1
INTRODUCTION
