Mode of operation

The FIDAMAT 6 performs substance-specific measurement and not component-specific measurement. It measures the total of all hydrocarbons in a sample gas, although with different weighting of the hydrocarbon molecules. At initial exposure, the display is proportional to the number of C atoms in the molecule in question. There are fluctuations in practice, however. The display deviation for the relevant molecule is expressed by the response factor.

The sample gas is supplied to the FIDAMAT 6 under overpressure or drawn in by the built-in diaphragm pump (optionally via a heated line and an additional filter) and passed into the flame ionization detector via an obstruction-proof fused-silica restrictor.

In the detector, the hydrocarbons in the sample gas are burned in a detonating gas flame. Burning partially ionizes the proportion of organically-bound hydrocarbons. The released ions are converted into a stream by the tension between two electrodes and measured using a highly sensitive amplifier. The current measured is proportional to the quantity of organically-bound C atoms in the sample gas.

A pressure regulator holds the combustion gas pressure constant. The balanced system of pump, capillary tubes, and combustion gas pressure regulators ensures that the sample gas pressure is kept constant.

When the analyzer is switched on, ignition and pump startup are automatic when the setpoint temperature has been reached.

FIDAMAT 6, mode of operation

The FIDAMAT 6 provides various messages in the form of floating contacts:

• Maintenance request
  E.g. sample gas flow (filter/pump)
  Fan failure (advance warning for measuring accuracy).
  The measured value remains unaffected.
• Fault
  E.g. hydrogen, combustion gas, and sample gas pressure, temperature, physical part and pump, fault in the electronics (temperature).
  The measured value can be influenced.
• Failure
  In the event of failure of, for example, the electronics, voltage supply, combustion gas, combustion air and sample gas, the device automatically shuts down (the combustion gas valve is closed).

Note

The sample gas needs to be free of dust. Condensate in the cells must be avoided. That is why the most measuring tasks require an appropriate gas preparation.

Essential characteristics

• Four freely-parameterizable measuring ranges, also with suppressed zero point, all measuring ranges linear
• Galvanically isolated measured value output 0/2/4 bis 20 mA (also inverted)
• Automatic measuring range switchover selectable, remote switchover also possible
• Storage of measured value during calibration possible
• Range identification
• Measuring-point selection for up to 6 measuring points
• Measuring point identification
• Time constants (static/dynamic noise suppression) can be selected within wide limits; this means the response time of the device can be adapted to the respective measuring task
• Simple handling thanks to menu operation
• Low long-term drift
• Two operation levels with separate authorization code to prevent unsupervised and unauthorized use
• Parameterizable automatic measuring range calibration
• Operation based on the NAMUR recommendation
• Customized device versions such as:
  • Customer acceptance
  • TAG labels
  • Drift recording
• Wear-free, corrosion-proof filter housing
• No obstructions in the sample gas restrictors through the use of a quartz restrictor tube
• Purge function in the event of device failure and auxiliary power failure (avoids build-up of toxic and corrosive substances in the device)
• Low combustion air consumption
• Response factors comply with the minimum requirements in accordance with German air purity guidelines and the Working Group of the German Automobile Industry
• Simple operation with the help of a numeric membrane keyboard and operator prompting.

Response factors (examples, mean values)

Cross influences (examples) ¹)

1) With measuring range 0 … 15 mg/m³.