CEMB USA T-NC-API-ATEX - Manual (Page 2)

2
PRINCIPLE OF OPERATION
The T-NC system generates a radio frequency field, which is radiated by the sensor
surface.
When the reference surface facing the sensor is impinged by such RF field, an eddy
current is generated on this surface. The energy required to generate this eddy current
(which is proportional to the distance between the reference surface and the surface of
the sensor), is reduced in proportion to that involved in the sensor; such difference
is picked up by the converter.
The converter amplifies and processes such signal by supplying, for the processing, a
d.c. output voltage proportional to the distance under examination.
COMPOSITION
Each transducer basically consists of a field sensor, an extension cable which can be
integral with the sensor or unpluggable from it through an intermediate connector, and
a demodulator, likewise unpluggable from the extension cable or sensor cable, which
transforms the picked up signal in a voltage suitable for processing.
TECHNICAL CHARACTERISTICS OF EACH SENSOR-DEMODULATOR CHAIN
Basic composition
: sensor, extension cable, demodulator
Type of measurement : differential
Dynamic range : frequency 0 to 10,000 Hz
amplitude max 2 mm (from 0.5 mm to 2.50 mm)
Linearity over the entire
range of measurement,
within the operating temp-
erature limits indicated : ± 1%
Rated scale factor
: 200 mV/mil (7,87 mV/µm)
Sensitivity to temperature : according to API 670
Power supply : -18 -24 Vdc; GND
Operating range
: . temperature (sensor) = -35 to +175° C
. temperature (convert) = -20 to +80°C
. humidity (sensor) = max 100%
. humidity (converter) = max 95% not condensing
. ambient (sensor) = IP67 EN 60529/10.91
. ambient (converter) = IP65 EN 60529/10.91
Connection : . miniaturized coaxial connector
(sensor / converter)
. screw terminal board model 476-CS/AL/3
(converter / instrument)
Weight of converter : approx. 0.30 Kg
Weight of one sensor : approx. 0.10 Kg
Maintenance : None
Drawings enclosed
: 52330-C = Dimensions-mounting-connections