User Manual & Datasheet V 2.1
and equi-phase relation between the sense and shield waveforms a high degree of immunity to probe coating and
build-up achieved. The probe head is of cast aluminium construction and is fitted on the probe extension, away from
heat. It is provided with a suitable mounting arrangement of the screwed or flanged type (as per order).
ELECTRONIC INSERT:
The electronic insert can either be directly mounted in probe housing or remotely in-
stalled in a separate housing. The electronic insert comprises of an RF Oscillator, Detector and Coat Immunizing
circuitry all encased in a plastic housing and potted with epoxy resin. Built-in terminals on electronic insert facilitate
interconnections. The Insert is further housed in a cast aluminium housing provided with a suitable entry and houses a
high voltage discharge device (Optional).
EVALUATION UNIT:
The evaluation unit consists of a step down transformer, rectifier, voltage regulator, os-
cillator, probe immunizing circuitry, set point adjusting capacitor, relay driving circuitry, fail-safe selection LED Indicator
and Relay. In case of time delay model, a separate timing mode selection switch and pot is provided for delay setting.
The electronics along with interconnecting terminals is assembled on a glass epoxy PCB heavily lacquered for rendering
it immune to moisture, dust and fungus.
The card in turn is mounted in a cast aluminium weather proof housing, stoved enamel painted & provided with 3 nos.
of cable entries. The measuring electrode and shield are connected to a radio frequency source. Due to the geometry of
construction and immuno coat circuitry, RF current does not flow between the measuring electrode and shield. Current
can, however, flow between the shield and mounting (ground) which being out of the measuring circuit does not effect
indication. The only path left for the current to flow through is the admittance path via the material to the vessel wall
(ground). This being the only path of interest, the system gives a reliable indication of level.
Figure 3: System Diagram
Sapcon Instruments Pvt.Ltd.
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