SENSOR FEATURES
The sensor housings are constructed of
PEEK, a high performance thermoplastic
that provides outstanding mechanical
strength and chemical resistance. Multiple
sealing materials are used to preserve
sensor integrity over a wide range of
applications.
The four electrodes used in the cell are
made of titanium for greater chemical
resistance. Two of these electrodes are
used to establish the sensor drive
potential. The other two electrodes sense
the flow of current between the drive
electrodes and maintain the proper drive
potential. The current that flows between
the two drive electrodes is directly
proportional to solution conductivity.
With conventional two-electrode sensors,
as the process solution begins to coat the
electrode surfaces, the sensor output
signal begins to decrease. This produces
an artificially low conductivity
measurement.
The CDTX-45 four-electrode system uses
electrode diagnostics to compensate for
the effects of fouling. As the two drive
electrodes become coated by the process
solution, a feedback mechanism involving
the two sensing electrodes detects the
decrease in drive potential and
automatically re-establishes the proper
drive potential. When the degree of coating
reaches a limit where compensation is no
longer possible, the diagnostic actuates an
alarm to signal that the sensor requires
cleaning.
The unique drive/control scheme of
this system allows a single sensor
configuration to be used reliably over a
wide conductivity range. This system
eliminates the requirement for multiple
sensors with varying cell constants that
are restricted to narrow operating ranges.
TRANSMITTER FEATURES
The microprocessor-based transmitter
is loop-powered and fully isolated for high
service reliability. The transmitter includes devices to protect
the system from power
surge and brownout events.
The large, high contrast, super-twist
display provides excellent readability over
a wide operating temperature range, even
in low light conditions. The main display
line consists of large, segmented
characters with measurement units. The
secondary display line utilizes easily
readable dot matrix characters for clear display of calibration and diagnostic
messages. Two of four measured
parameters may be displayed
simultaneously.
Four-button programming provides intuitive
navigation through the menu-driven user
interface. The 4 to 20 mA transmitter
output can be configured to represent any
portion of the measurement range. Output
HOLD, ALARM and SIMULATION features
provide the user with complete control of
the system output under any condition.
Diagnostic messages provide a clear
description of system condition, which
eliminates confusing error codes that must
be looked up in the operator’s manual.
The flexible calibration method includes
stability monitors that check temperature
and main parameter stability before
accepting data.
