130-0047 Issue 8
Page 4 of 18
3.4 Connections
The sensor, output signals and the supply should be connected as
shown below. See section 3.8 for details of optional remote sensor
version.
Terminal 1 Sensor +ve (red wire)
" 2 Sensor -ve (black wire)
" 3 Analogue Output +ve
" 4 " " -ve
" 5 Alarm 1 common terminal
" 6 " " N/C terminal
" 7 " " N/O terminal
" 8 Not used
" 9 " "
" 10 " "
" 11 Mains Live (or DC +ve )
" 12 Mains Neutral (or DC -ve)
" 13 Mains Earth
N/C= Normally closed N/O= Normally open
Note: 1) Terminal 1 is at the left-hand end of the connector when
viewed from the rear. 2)"Normal" refers to the alarm status, not the
electrical rest position of the relay.
3.5 Sample connections
The standard sample connections are shown in Fig. 2. It is
important that the sample being supplied to the analyser is clean
and non-corrosive. Filters or chemical absorbers will be necessary
for those samples that contain particulate matter or corrosive
components. Additionally the dew-point of the sample should not be
above the ambient temperature.
If site or process conditions require that the process is isolated from
the analyser when the sensor is changed then shut-off valves
should be fitted to the inlet and outlet of the measuring sensor. The
inclusion of a three way valve on the inlet side can also be used to
allow easy connection of a standard gas for calibration checks. It is
particularly important that good pipework connections are made
when low levels of oxygen are being measured.
Page 5 of 18
For all parts per million (ppm) measurements the pipework
should be all metal or hard plastic (Nylon, un-plasticised P.V.C.
etc.) up to the inlet of the measuring sensor. Flowmeters and
pumps must be suitable for handling ppm levels if placed on
the inlet to the sensor; see comments on Fig. 2. Note that the
sensor is shipped with its inlet tube plugged. Do not remove
this plug until you are ready to fit the sensor to the instrument.
Fig. 2
General sampling system arrangement
Sample outlet
Optional
pump
position
Flow meter
The flow meter and pump can be placed on the inlet if it is more
convenient and both are adequately leak tight etc. for use at the
concentration of oxygen being measured. If either or both are not
suitable they should be put in the sample outlet pipework. To reduce
the effect of any back diffusion, a vent pipe must be connected
to the sample outlet in all cases and this must be at least 300mm
long if nothing else is fitted to the outlet.
Sample inlet
Calibration gas
inlet
Pipework and fittings shown
dotted are optional
Sample
Pump
Filter
Sample Flow
ML/MIN
250
200
150
100
50
Flow
control
valve
Sample outlet
and inlet
suitable for ¼"
or 6mm
diameter tube
Sensor
1
+
Cell
5
C
Alarm 1
C
Alarm 2
93
+
An.O/P
7
NO NO
11
L
Danger
Mains
13
E
2
-
6
NC NC
104
-
8 12
N
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