Siemens FIDAMAT 6, Руководство по эксплуатации, Страница: 29 / 202

Description
3.4 Method of operation
FIDAMAT 6
Operating Instructions, 01/2019, A5E00222135-04
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In a first approximation, the display is proportional to the number of C atoms in the
respective molecule. However, there are deviations in practice. The display deviation for the
specific molecule is expressed by the response factor.
FIDAMAT 6-E: The sample gas is drawn into the FIDAMAT 6-E by the integrated diaphragm
pump and is carried under overpressure over a heated line and an additional filter. It arrives
at the flame ionization detector via a clog-proof restrictor.
FIDAMAT 6-G: The sample gas is supplied to the flame ionization detector in the
FIDAMAT 6-G under overpressure via a clog-proof restrictor.
The hydrocarbons contained in the sample gas are combusted in an oxyhydrogen gas flame
in the flame ionization detector. During combustion, the organically bound hydrocarbon part
is ionized. The released ions are converted into an ion current by the polarization voltage
existing between two electrodes and measured using a highly sensitive amplifier.
The measured current is proportional to the number of organically bound C atoms of the
hydrocarbons in the sample gas.
A pressure regulator keeps the combustion gas pressure constant. A constant sample gas
pressure is ensured by the coordinated system, which is made up of capillaries and a
pressure regulator for combustion air and, in the case of the FIDAMAT 6-E, a pump.
After switching on the analyzer, the flame will be ignited as soon as a temperature of 155 °C
is reached in the FID. You can use function 2 "Diagnostic values" to retrieve the current
temperature of the FID under "Flame".
FIDAMAT 6-E: When the flame has reached a temperature of 220 °C (430 °F), the pump
startup begins automatically.
The FIDAMAT 6 transmits various messages outward in the form of floating contacts:
● Maintenance request:
–
Fan failure (preliminary warning for measuring accuracy)
– Sample gas flow (filter/pump) for FIDAMAT 6-E only
After a maintenance request, the device continues measuring normally. The measured value
is not influenced.
● Fault:
–
Hydrogen, combustion air and sample gas pressure, temperature, physical part (for
FIDAMAT 6-E with pump), faults in the electronics (temperature).
If the measured value is influenced, the device may switch to another operating state
(combustion gas valve is closed).
Note
The sample gases fed to the device must be free of dust and condensation. To prevent
condensation, it is necessary in most applications to use a gas preparation system adapted
to the measuring task.