The probe is immersed directly into the medium to be monitored via a probe port. Alcohol from the measuring solution (methanol or ethanol) diffuses via a special membrane system into a measuring chamber through which carrier gas flows. Via the carrier gas the alcohol is transported to a semiconductor gas sensor. The changing resistance of the sensor is evaluated by a measuring amplifier under consideration of a temperature compensation.
The «Transmitter S7» used as measuring amplifier is designed for the connection of one to four probes but can also be extended to any number of probes. The calibration of the probes is done on a touch panel. The alcohol concentration and the temperature are displayed online. The output of the measured values to your process control system is done via an analog module as 4 – 20 mA signal or via a digital interface via OPC.
The transmitter S7 as well as all necessary electrical connections including the carrier gas supply are installed in a switch cabinet (protection class IP 65) made of stainless steel. All lines are led out of the switch cabinet via PG screwed connections.