INM MTL 130-0175 Rev 4
7
Slowly open the flow valve beneath the flow meter until a flow of between 150 and 250 ml/min
is flowing.
WARNING
To avoid serious and dangerous damage to the catalyst and sensor the sample
flow must not exceed 250ml/min (0.5cuft/hr).
The instrument will respond within a few seconds to show the oxygen concentration.
NOTE:
Combustion of the sample generates heat and it is possible, when the sample is first
applied, that the catalyst temperature may go higher than its normal control point before
the controller is able to react. This will cause the controller to show error condition and the
relay contacts to go a fault condition. Whether this occurs or not will depend on the sample
composition and its flow rate. The results during this transient state are valid. It is suggested
that any external equipment (PLC’s etc) used to monitor the analyser are programmed so as to
ignore this situation for approximately 60 seconds after the sample has been applied.
Before switching the analyser off following its use on combustible samples ALWAYS pass air
through the analyser for a few minutes to purge out the moisture etc. formed when combusting
the sample.
4.5 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:
Alarm 1 Set point Alarm 1 Mode Alarm 1 Hysteresis Alarm 2 Set point Alarm 2 Mode
Alarm 2 Hysteresis Analogue Output top scale value Return to measurement mode.
NOTE
Only the LED indicators are available for the concentration alarms. No relay output is
provided on this model.
ALARM 1 - 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 1 LED will flash.
“xxxx”
is the value
of the alarm set point and the flashing LED indicates that it is the set point of alarm 1. 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 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 1 LED will continue to
flash.
