3
1.
Introduction
1.1 Description
The Mark 25 Conductivity Analyzer is a simple, low cost,
4 channel
, microprocessor-
based monitoring system designed for ultrapure water applications. The system
consists of a readout module that can be used with up to four sensors; each sensor
being incorporated into a flow-through style flow chamber.
A large 4 digit LED display indicates either
temperature
,
raw conductivity
, or
temperature-corrected conductivity
while an 8-key membrane keypad allows the
operator to quickly setup and calibrate the analyzer.
The Mark 25 measures conductivity in
three ranges
; 0-1
µ
S/cm, 0-10
µ
S/cm, and 0-
100
µ
S/cm. Calibration is accomplished quickly via automatic calibration within the Mark
25 or by comparison to a referee system (please refer to Martek’s ASTM & NIST-
traceable
Mark 22 In Situ Calibrator
for further information).
Four alarm set points with relay contacts are standard in addition to four isolated analog
recorder outputs (0-20 mA)
and
a serial RS232 digital output for hookup to external
recording equipment. For maximum flexibility,
alarm set points and analog outputs
can be assigned to any range on any parameter on any channel.
Housed in a ¼ DIN corrosion-resistant plastic case, the readout module can be panel
mounted with a minimum of tools. The analyzer accepts power inputs from 97 to 240
VAC 50/60 Hz or 24 Vdc and comes with an
ON/OFF switch
located on the rear panel.
Alarm and recorder wires are easily installed in removable terminal strips.
Sensors connect via a DB-9 connector located on the rear panel of the Mark 25 and the
sensors mount easily to any flat surface. In addition, Martek offers
adapter plates
specifically designed to cover the space occupied by other brands of conductivity
analyzers.
Sensors come standard with 10 feet (3 meters) of cable. However, longer cable lengths
may be special-ordered from the factory up to lengths of 150 feet.
NOTE: If the Mark 25 is purchased as a part of the Dissolved Carbon Dioxide
Analyzer, the auto-ranging function is standard and cannot be changed. For
additional information, contact the factory.
