50-604 Kotron Model 804 Sentinel II RF Level Transmitter
1
1.0
Description
The Sentinel II is a unique, powerful level transmitter.
The leading-edge microprocessor-based circuitry has
non-volatile memory that requires no battery backup. To
simplify troubleshooting, powerful diagnostics not only
check all aspects of the system, but will actually indicate
the faulty section of the system. MagneCal™ offers the
user the greatest improvement in RF Capacitance—
one
small level change (2% of span) is needed to calibrate.
1.1
Principle of Operation
The amount of capacitance developed in any vessel is
determined by the size (surface area) of the probe, the
distance from the probe to its ground reference, and the
dielectric constant of the medium being measured.
Assuming that the probe's mounting position and the
dielectric of the medium are fixed, the amount of capaci-
tance developed in any vessel becomes dependent upon
the probe's diameter and length. Adjusting the combina-
tion of the probe's diameter and length (and its proximity
to a ground reference) can generate the necessary capaci-
tance required by the electronic circuitry.
As the media rises and falls in the tank, the amount of
capacitance developed between the probe and the ground
reference also rises and falls. The capacitance-controlled
oscillator circuit mounted on the probe changes the
capacitance signal to a a digital wave form—proportional
to the change in level. The Series 804 amplifier then
converts this digital pulse signal into an isolated 4–20 mA
analog output signal.
1.2
Unpacking
Unpack the instrument carefully making sure all compo-
nents have been removed from the packing material.
Inspect all components for damage and report any con-
cealed damage to the carrier within 24 hours.
Check the contents of the carton making sure it agrees
with the packing slip and the purchase order. Verify that
the model number imprinted on the nameplate matches
the number on the packing slip and the purchase order.
Report any discrepancies to the factory. Check and record
the serial number for future reference when ordering parts.
