130-0047 Issue 8
4.0 COMMISSIONING
4.1 Switching on
When the analyser is fully connected, it may be switched on. When
switched on, the analyser automatically enters normal measurement
mode. Depending on which sensor is fitted, the analyser may
initially indicate a high oxygen reading. After a few minutes the
reading will settle to a level dependent on the sample being supplied
to the sensor. The analyser is calibrated prior to shipment and may
be used immediately. To check calibration see section 5.
4.2 Programming
The user programmable features are accessed by pressing and
holding the
Edit
button for approximately 8 seconds when the
instrument is in normal measurement mode. Each subsequent
momentary press of the
Edit
button scrolls the display through a
sequence of adjustable parameters. The order of the sequence is
as follows:
% version
Alarm Set point
→
Alarm Mode
→
Alarm Hysteresis
→
Return to
measurement mode.
PPM version
Alarm Set point
→
Alarm Mode
→
Alarm Hysteresis
→
Analogue
Output top scale value
→
Return to measurement mode.
ALARM - Set point
This is the first parameter to be displayed when the
Edit
button is
pressed and held for eight seconds. The display will show “E xxxx”,
and the Alarm LED will flash. “xxxx” is the value of the alarm set
point and the flashing LED indicates that it is the alarm set point. To
the right of the display a % or ppm symbol is displayed to indicate
the units of the value displayed. To change the value of the set
point, press the up/down arrows until the display shows the required
value. Observe the “%” and “ppm” symbols to ensure the correct
setting. When the buttons are first pressed, the value changes
slowly and the least significant number can be changed by
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giving the buttons a short “click”. If the button is kept depressed the
rate accelerates rapidly to enable large changes in value to be
achieved quickly. Once the required value is displayed, press the
Edit
button once to store the value in the analyser’s memory.
Simultaneously the display will change to show “E x” and the
Alarm LED will continue to flash.
ALARM - Mode
The symbol displayed in the “x” position indicates the mode of the
alarm as follows;
0 - Alarm off; H - High; L - Low. Press the arrow buttons to change
the mode and press the
Edit
button once to store the setting. The
display will change to show “EH xx” and the Alarm 1 LED will
continue to flash.
ALARM - Hysteresis
The number displayed In the “xx” position indicates the value of the
hysteresis for alarm 1. The value is given in percentage of the set-
point or alarm level and is variable from zero to 10%. Press the
arrow buttons to set the required value and then
Edit
button to
store the value. The display will then change to repeat the above
sequence for
alarm 2
; indicated by the
alarm 2 LED flashing.
ANALOGUE OUTPUT - Top scale value (PPM version only)
When the
EDIT
button is pressed following alarm hysteresis entry,
the display will show “EPxxxx”, where “xxxx” is the oxygen
concentration at which the analogue output ( 0 to 5v or 4 to 20mA)
is at top scale. The alarm LED does not flash. Press the up/down
arrow keys to scroll the display through the pre-set values of
200ppm and 2000ppm. Once the required value is selected, press
the
Edit
button to store the value and return to measurement
mode.
4.3 Applying the sample
Establish a sample flow of between 100 and 300ml/min. The
analyser will respond immediately and move towards displaying the
concentration of oxygen in the sample. The speed of response
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