Siemens FIDAMAT 6 Operating Instructions Manual page 22

Description
2.4 Method of operation
The sample gas is drawn into the FIDAMAT 6-E by means of 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 fused silica restrictor. The hydrocarbons contained
in the sample gas are combusted in an oxyhydrogen gas flame in the 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. The balanced system of
pump, capillary tubes and pressure regulator for combustion air ensures that the sample gas
pressure is kept constant.
After the analyzer is switched on, the flame is ignited as soon as a temperature of 150 °C
(300 °F) is reached in the FID. You can use function 2 "Diagnostic values" to retrieve the
current temperature of the FID under "Flame". 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:
– Sample gas flow (filter/pump)
– Fan failure (preliminary warning for measuring accuracy)
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 with
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.
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pump, faults in the electronics (temperature).
Operating Instructions, 03/2018, A5E00222135-03
FIDAMAT 6