10
INM MTL 130-0202 Rev 4
4
OPERATION
4.1 First checks
It is advisable to make a thorough check of all connections – particularly the pipe work –
before applying any sample.
WARNING
Chlorine is a highly toxic and corrosive gas and it is of utmost importance that
there are no leaks. In particular, ensure that all unions are fully tightened and
that the fragile reactor tube is not damaged.
4.2 Flowing the sample
With these checks complete, power may be applied to the instrument. Following the
initialisation screen, the display will indicate that it is waiting for the reactor to reach
temperature. When the correct operating temperature is reached, the analyser will enter
normal measurement mode automatically. The sample may now be applied. A sample
flow of between 100 and 300 ml/min is suggested, although flows up to 400ml/min may be
applied. (100ml/min = 0.212cuft/hr)
Once the sample pipelines have been purged the instrument display will show the hydrogen
and chlorine concentrations. A warm-up time of approximately 15 minutes after the reactor
has reached its operating temperature should be allowed in order to obtain the best accuracy.
The instrument is supplied fully tested and calibrated and may be used immediately.
4.3 Configuring the analyser
This enables the user to step through a range of display screens and define (program) specific
parameters, such as alarm levels, ranges, etc. The screens also provide data on the model
and the software revision of the analyser. The following table describes the function and
parameters available at each screen. There is also a diagram of the screen levels followed by
a description of how to set the parameters.
4.3.1 Parameters
Screen
Function
Parameter
Description
1
Alarm 1 (Hydrogen
Concentration)
Alarm Level
Adjustable from 0 to 5% or 0 to 10% (model dependant) in 0.01% steps
Hysteresis
Adjustable from 0 to 2% of span in 0.01% steps
Alarm Mode
Can be set to High, Low or Off
2
Alarm 2 (Chlorine
Concentration)
Alarm Level
Adjustable from 0 to 100% in 0.1% steps
Hysteresis
Adjustable from 0 to 20% of span in 0.01% steps
Alarm Mode
Can be set to High, Low or Off
3
Hydrogen Span
Calibration Level
Level
Concentration level adjustable from 1.50 to 2.00% in 0.01% steps
4
Chlorine Span
Calibration Level
H
2
Cl
2
NOTE: The facility to set the hydrogen concentration in this screen is to facilitate
calibration on a plant sample when the hydrogen concentration is known from other
analysers. If pure chlorine OR pure argon (the surrogate for chlorine) is used for chlorine
span calibration, the hydrogen level in this screen MUST BE SET TO ZERO.
5
4/20mA function
Cal.
Fault
Define the action of the analogue output, when the analyser is in calibration or fault
conditions. Set either to Follow (track) the display or Hold the last value immediately
prior to the condition occurring.
6
H
2
4/20mA
20mA
Set top H
2
scale value. Adjustable from 1.00% to 5.00% in 0.01% steps, or 2.00% to
10.00% in 0.01% steps. (model dependant)
7
Filter
Level
A digital filter to ‘smooth’ rapid display changes. Set level between 0 and 9 (represents
factor of 0.0 to 0.9).
Displayed change = Actual change x (1 – factor)
e.g. Change of 50% up to 70% with Level = 5 would result in 20% x (1 – 0.5) = 10%;
hence next display is 50 + 10 = 60%
8
Samples, ranges
and output
–
Displays analyser type, ranges measurable, and type of output
9
Sensor & software
–
Displays sensor serial number, software and version data.
