Martek Instruments Mark 25 Instruction Manual

Martek Instruments, Inc.

Mark 25

Ultrapure Water
Conductivity Analyzer

Instruction Manual

WARRANTY POLICY

Unless otherwise stated, MARTEK INSTRUMENTS, INC. warrants this equipment
to be free from defects in material and workmanship and to perform in
accordance with applicable specifications for five years (one year for portable
equipment) from date of shipment. All conductivity sensors are guaranteed for
life.

MARTEK will provide free service at the factory, including parts, labor and
transportation back to the customer, for any malfunction of its products which
are returned transportation charges prepaid.

Customers desiring to return a product to MARTEK for repair should contact the
Service Department by telephone at [phone] or fax [phone] or via
our website at www.martekinstruments.com to obtain return authorization. The
information required at this time will be the complete model number and serial
number of the product and a brief description of the problem.

All shipments to MARTEK must be freight prepaid and addressed as follows:
MARTEK INSTRUMENTS, INC.

2609 Discovery Drive
Raleigh, NC 27616
Attn: Repair Department

A complete and detailed statement of the reason for return must accompany the
unit. If possible, include a copy of sample reading or a printout.

Returned units must be packed as well as they were when first shipped. If
possible, use the original packing. Do not return detachable cords or manuals
with the unit.

MARTEK reserves the right to void this warranty if the product has been
subjected to misuse, neglect, accident, improper installation or application, and
for consumable items such as batteries, membranes, or solutions.

This warranty is expressly in lieu of all other obligations or liabilities on the part
of MARTEK. MARTEK neither assumes nor authorizes any other person or
organization to assume on behalf of Martek any other liability in connection with
the sales or use of MARTEK instrumentation.

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MARK 25 TABLE OF CONTENTS

1. Introduction Page

1.1 Description ……………………………………………………………………………….3

1.2 Specifications ……………………………………………………………………………4

2. Installation

2.1 Panel Cutout for Monitor ..………………………………………………………………5

2.2 Sensor Dimensions …………….……………………………………………………….5

2.3 Electrical connections to the monitor ……………………………………………….…6

3. Operation

3.1 Keyboard & display ……………………………………………………………………….7

3.2 The CALIB Key...…….….…………………………………………………………………7

3.3 Calibrating Temperature.…………………………………………………………………8

3.4 Calibrating Conductivity.….……………………………………………………………….9

3.5 Setting Alarms…………….. …….………………………………………………………..9

3.6 Setting Recorder Outputs….……………………………………………………………10

3.7 Setting the Password..…….…………………………………………………….……….11

3.8 Setting the ID Number…………………….……………………………………………..11

3.9 Changing the Serial Output……………………………………………………….……..11

3.10 Setting the Auto-Ranging Function….…………………………………………….….12

3.11 Troubleshooting……………………….…………………………….…………………..12

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1. Introduction

1.1 Description

The Mark 25 Conductivity Analyzer is a simple, low cost, 4 channel, microprocessor­based 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 µS/cm, 0-10 µS/cm, and 0­100 µS/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 & NIST­traceable 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.

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1.2 Specifications

Parameter Range Accuracy Resolution

Conductivity

Temperature 0-100o C +0.1o C 0.01o C

0-1.000 µS/cm +0.01 µS/cm 0.001 µS/cm
0-10.00 µS/cm +0.1 µS/cm 0.01 µS/cm
0-100 µS/cm +1.0 µS/cm 0.1 µS/cm

Power: 97-240 VAC, 50/60 Hz, 24Vdc, fuse protected
Recorder Output: Four isolated, scaleable 0-20 mA DC analog & RS232C serial ASCII digital output
Alarm Output: Four solid-state relays, 5 amp, 250 V
Weight: 2 lbs (0.9 kg) including one sensor with 10 feet (3 meters)
Construction: Readout Module Case: ABS plastic, NEMA 12 (IP65)

Sensor: Type 316 Stainless Steel and Teflon

Cabling: 8-conductor, 24 gauge, PVC jacket, shielded, 0.25 inch (0.63 cm)
Dimensions: ¼ DIN case, 6.51 x 3.78 x 3.78 (165.5 x 96 x 96 mm) LWH

Installation: Panel mount (mounting hardware included). Recommend mounting sensor

vertically with inlet at the bottom. Position of sensor cabling not a factor in
mounting.

Flow rate: 45-250 ml/min

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2. Installation

2.1 Panel Cutout for Monitor

3.60”

3.60”

Panel Cut-out

2.2 Sensor Dimensions

2.75”

(6.98 cm)

1.75”

(4.44 cm)

Side View

8.00” (20.32 cm)

1.12”
(2.84 cm)

Top View

.125” (.31 cm) .196” (.49 cm)
2 places

4.125” (10.47 cm)

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2.3 Electrical connections to the monitor

Alarm Outputs Recorder Outputs

ON/OFF
Switch

AC Cord

RS232
Digital Output
RS232 1 2 3 4

Sensors

To set up the Mark 25 for operation, simply plug the sensor connector in, then plug the
AC power cord into a properly grounded outlet. If recorder, digital or alarm outputs are
to be used, make certain the Mark 25 is unplugged before connecting the cable to the
appropriate recorder or computer. Follow the wiring diagram below for hooking up the
Mark 25 alarm and analog recorder outputs:

ALARM RECORDER

Channel 1 NO/NC Channel 1 4-20 mA
COMMON

Channel 2 NO/NC Channel 2 4-20 mA
COMMON

Channel 3 NO/NC Channel 3 4-20 mA
COMMON

Channel 4 NO/NC Channel 4 4-20 mA
COMMON

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3. Operation

3.1 Keyboard and display

The Mark 25 front panel consists of a
4 digit red LED display, 3 parameter and
channel LED’s, an alarm LED, and an 8­key keypad. The display is used to
present all parameter measurements,
operator prompts and system errors.

The keys are arranged in two rows, four
keys in each row.

The top row of keys consist of three
color-outlined function keys and are
used to perform instrument operations
such as selecting which parameter to
view, what range the parameter is to be
viewed in, parameter calibration and
system set up.

The bottom row of keys are multi­colored, multi-legend keys and are used
in conjunction with the function keys.
The same colored legends correspond
to the same colored function key.

The arrow keys are used to view
channels, select functions during setup
and calibration, and increment or
decrement a displayed value.

READ Range CALIB

LOW

MED
RAW

SPAN

HIGH

TC

RUN

o

C

ZERO

READ key - When the <READ> key is

pressed, the Mark 25 will display rd. If
one of the bottom keys is selected, the
parameter high-lighted in red will be
displayed and its corresponding LED lit.

RANGE key - Range changes can be
made manually for raw conductivity and
temperature-corrected conductivity only.
To change the range, press the
<RANGE> key, then select
either LOW, MED, or HIGH to display
the desired range. If the Mark 25 is
setup for auto-ranging, the Mark 25 will
display AUrg as long as the <RANGE>
key is pressed.

NOTE: Manually changing the range for
temperature-corrected conductivity
changes the analog recorder output
scaling. See Section 3.7 for details.

Viewing a different channel is easily
done by pressing the <UP> or <DOWN>
arrow key. The parameter LED’s to the
left of the Mark 25 display also indicate
which channel is being viewed. Channel
ID’s are as follows:

Red LED - Channel 1
Green LED - Channel 2
Red/Green LED - Channel 3
Flashing Red LED - Channel 4

3.2 The CALIB key

All setup and calibration functions are
conducted via the <CALIB> key. The
<CALIB> allows you to set the following:

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• Calibrate temperature and
conductivity

• Assign and set alarm points

• Assign and set recorder outputs

• Set a password

• Set up an analyzer ID, serial

output, and auto-ranging
functions

Once the sensors have been connected
to the Mark 25, the power cord can be
plugged into any outlet supplying 97-240
V AC 50/60 Hz power. When the Mark
25 is switched on, it will immediately
start monitoring temperature.

Pressing the <CALIB> key will cause
the Mark 25 to display a flashing oC.

If you continue pressing the <DOWN
ARROW> key the display will flash the
following prompts: CON, ALA, rEC,
PAS, uSr. After uSr, the Mark 25
returns to monitoring temperature.

Here are two basic rules to remember
when using the <CALIB> key:

1. Pressing the <UP ARROW> key will
select any flashing prompt.

2. Pressing the <RUN> key will return
the Mark 25 to the monitoring mode.

3.3 Calibrating Temperature

The Mark 25 can be calibrated
automatically or manually for
temperature.

NOTE: Automatic, electronic calibration
is a less accurate method of calibration.
For best results, the Mark 25 should be
calibrated to ASTM or NIST- traceable
standards.

To calibrate temperature, press the
<CALIB> key. The display will flash oC.

To select temperature, press the <UP
ARROW> key. The flashing will stop.
Next, press the <ZERO> key. The Mark
25 will display three calibration bars and
automatically zero the temperature
before returning to the monitoring mode.

To span temperature, press the
<CALIB> key, then the <UP ARROW>
key when the temperature prompt is
displayed. Next, select the <SPAN> key.
The Mark 25 will display Aut which is
short for Automatic.

To automatically calibrate temperature,
press the <UP ARROW> key. After the
calibration bars appear, the Mark 25 will
briefly display a span temperature of

50.0 before returning to monitor mode.
The Mark 25 has now been calibrated

for temperature.
To manually span calibrate temperature,

simply press the <DOWN ARROW> key
when Aut is displayed. The Mark 25 will
momentarily display three lines, then a
number indicating the input voltage will
appear in the display. Once this number
has stabilized, press the <CALIB> key
and select the appropriate span value
using the up or down arrow keys (the
display defaults to 25 deg. C). When
complete, press the <CALIB> key to
enter the data into the Mark 25’s
memory.

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3.4 Calibrating Conductivity

Calibrating conductivity follows the
same procedure as the temperature
calibration. However, if the Mark 25 is
not set up for auto-ranging prior to
conductivity calibration, the desired
range must be selected (for information
on auto-ranging, see section 3.10 Auto-
ranging).

Press the <CALIB> key, then the
<DOWN ARROW> key until CON is
flashing. Follow the same procedure for
zero calibration for conductivity that was
used for temperature.

To span conductivity, press the
<CALIB> key and select the conductivity
prompt. Next, press the <UP ARROW>
key when the Aut prompt is displayed.
The Mark 25 will display the calibration
bars then briefly display 1.000 (or 10.0
or 100.0 depending on the range
previously selected) before returning to
the monitor mode.

NOTE: If the auto-ranging function is
OFF and the Mark 25 is monitoring raw
or temperature-corrected conductivity
and the measurement exceeds the
current selected range, the Mark 25 will
display Err. The decimal point will
indicate the range previously selected. If
an error message occurs, you must
select a higher range.

3.5 Setting Alarms

The Mark 25 has four alarm set points
that can be assigned to any parameter
on any channel.

Press the <CALIB> until the display
indicates the alarm prompt, ALA. Next,
press the <UP ARROW> key. The
display will prompt with AL 1 and all

parameter LED’s will be lit. The <UP
ARROW> key can be used to change
the alarm set point to 2, 3, or 4.

To assign a particular alarm set point,
press the <CALIB> key. The Mark 25
will display three bars. The bars indicate
no alarm set point. Use the <UP> or
<DOWN ARROW> keys to select
temperature (t), raw conductivity (rc), or
temperature-corrected conductivity (tc).
Press the <CALIB> key to select the
desired parameter.

The Mark 25 will then display Lo. To
select a low set point, press the
<CALIB> key. If a high alarm set point is
desired, use the <UP> or <DOWN
ARROW> key to change the display to
hi then press the <CALIB> key to
select.

The Mark 25 will display .000 (if raw or
temperature-corrected conductivity is
selected) though the decimal point may
vary depending on the range previously
selected.

Use the <UP> or <DOWN ARROW>
key to change the value to the desired
alarm set point. When the desired set
point is reached, press the <CALIB> key
to set and activate alarm.

NOTE: For convenience, pressing the
<RANGE> key will advance the digit left
of the decimal point.

To disable alarm, return the set point
value to .000.

Once an alarm set point has been
assigned to a particular parameter on a
channel, it cannot be assigned to
another parameter or channel until it
has been disabled.

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When the Mark 25 reaches an alarm
state, the Alarm LED will light and the
alarm relay activate. The factory-set
position for the alarm relays is
NORMALLY OPEN. To change to a
NORMALLY CLOSED position, contact
Martek Instruments.

NOTE: The Alarm LED will blink if there
are active alarms that are not being
viewed and will remain steady if the
channel viewed is in an alarm state.

3.6 Setting Recorder Outputs

The Mark 25 comes standard with four
4-20 mA analog recorder outputs and
one RS232 digital output. Like the alarm
set points, the four analog recorder
outputs can be assigned to any range of
any parameter on any channel.
Press the <CALIB> until the display
indicates the recorder prompt, rEC.
Next, press the <UP ARROW> key. The
display will prompt with ou 1 and all
parameter LED’s will be lit. The <UP
ARROW> key can be used to change
the recorder output to 2, 3, or 4.

To assign a particular analog output,
press the <CALIB> key. The Mark 25
will display three bars. The bars indicate
no analog output assigned. Use the
<UP> or <DOWN ARROW> keys to
select temperature (t), raw conductivity
(rc), or temperature-corrected
conductivity (tc).

NOTE: A decimal point will be present
for rc and tc which indicates what range
these parameters are currently using. If
the auto-ranging function is ON, the
decimal point can be moved by pressing
the <RANGE> key.

Press the <CALIB> key to select the
desired parameter.

At this point, the standard 4-20 mA
output range can be changed to any
value desired. In addition, a “balance” is
provided to “fine-tune” each end of the
recorder range.

To change the lower end of the recorder
range, press the <ZERO> key. The
Mark 25 will display 4.00. Use the <UP>
or <DOWN ARROW> key to change the
number to the desired value. When the
desired value is reached, press the
<CALIB> key to set the value in
memory.

At this point, the Mark 25 will then
display 000. This is the “balance”. Use
the <UP> or <DOWN ARROW> key to
change the value in order to make the
lower end of the recorder range to agree
with the external recorder. When the
desired balance is reached, press the
<CALIB> key to set the value in
memory.

The same procedure is used to change
and “balance” the upper range of the
recorder output.

To disable any assigned analog
recorder output, select the particular
output and press the <CALIB> key.
Once the parameter is displayed, use
the <UP> or <DOWN ARROW> keys
until three bars are displayed. Press the
<CALIB> key to disable the output.

Once a recorder output has been
assigned to a particular parameter on a
channel, it cannot be assigned to
another parameter or channel until it
has been disabled.

NOTE: When the auto-ranging function
is OFF, changing a conductivity range
with an assigned analog output
automatically changes the scaling of the

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recorder output to the new range.
When the auto-ranging function is ON,
the assigned analog output will remain
in the range it was assigned to.

When the RS232 digital output is used,
calibration is not necessary. However,
the receiving computer must be set up
to accommodate the Mark 25’s digital
output configuration:

Baud Rate - 9600
Parity - Even
Word length - 7
Stop Bit - 1

A communication program such as
PROCOMM or Microsoft HYPERLINK
can be used to write data from the Mark
25 to a computer file which can then be
imported into a spreadsheet program
such as EXCEL or LOTUS NOTES.
The data will be displayed in the
following format:

ID, Chan, Temp. Raw Cond., TC Cond.

3.7 Setting the Password

The Mark 25 can be assigned a numeric
password to prevent unauthorized
personnel from changing any of the
settings.

Press the <CALIB> until the display
indicates the password prompt, PAS.
Next, press the <UP ARROW> key. The
display will prompt with 1999 and all
parameter LED’s will be lit and flashing.
Use the <UP> or <DOWN ARROW>
keys to change the displayed value to
any number other than 0. When the
desired value has been reached, press
the <CALIB> key to set and activate the
password.

Once the password is enabled, the
display will default to 1999 whenever the
password prompt is selected. To gain
access to any other function, you must
use the arrow keys to scroll to the
correct value password then press the
<CALIB> key.

To disable the password, use the <UP
ARROW> key to move the value to 0
then press the <CALIB> key. The
password function will then be disabled.

3.8 Setting the ID Number
The Mark 25 can be assigned a three

digit numeric ID number that will be
displayed on the digital output.

Press the <CALIB> until the display
indicates the user prompt, uSr. Next,
press the <UP ARROW> key. The
display will prompt with id and all
parameter LED’s will be lit and flashing.
When the <CALIB> is pressed, the Mark
25 will display 000. To assign an ID
number, use the <UP> or <DOWN
ARROW> keys to change the displayed
value to any number other than 000.
When the desired value has been
reached, press the <CALIB> key to set
the ID number.

To disable the ID number, use the <UP
ARROW> key to move the value to 000
then press the <CALIB> key. The ID
function will then be disabled.

3.9 Changing the Serial Output
The Mark 25 provides a standard

RS232 digital output. This output can be
configured in one of two ways:

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1. Polling - The Mark 25 will provide the
digital output only when polled by the
host computer.

2. Periodic - The Mark 25 will
automatically provide a digital output
at a 30 second interval.

Press the <CALIB> until the display
indicates the user prompt, uSr. Next,
press the <UP ARROW> key. The
display will prompt with id and all
parameter LED’s will be lit and flashing.
Use the <UP> or <DOWN ARROW>
key to advance to the serial prompt,
SEr. When the <CALIB> is pressed, the
Mark 25 will display PoL. To change the
output to periodic interval, press either
the <UP> or <DOWN ARROW> key
until the Mark 25 displays PEr.

To return to the monitor mode, press the
<RUN> key.

3.10 Setting the Auto-Ranging

Function

The Mark 25 can be set up to
automatically range between the low,
medium, and high ranges for raw and
temperature-corrected conductivity.

Press the <CALIB> key until the display
indicates the user prompt, uSr. Next,
press the <UP ARROW> key. The
display will prompt with id and all
parameter LED’s will be lit and flashing.
Use the <UP> or <DOWN ARROW>
key to advance to the auto-ranging
prompt, AUrG. When the <CALIB> key
is pressed, the Mark 25 will display
OFF. To activate the auto-ranging
function, press either the <UP> or
<DOWN ARROW> key until the Mark
25 displays On. Press the <CALIB> key

to activate the selection in the Mark 25’s
memory.

Pressing the <RUN> key returns the
Mark 25 to monitor mode.

3.11 Troubleshooting

The Martek Mark 25 represents over
thirty years of experience in conductivity
measurements and, as such, has been
designed to provide simple, reliable
operation for many years.

To obtain optimum performance from
the Mark 25, care should be taken to
ensure the sensor has adequate flow
and is free of obstructions. In addition, it
is important to maintain correct
calibration on a regular basis.

Comparison of the Mark 25 to a referee
system is the preferred method of
validation, however, calibration using
the Mark 25’s internal circuitry is also
acceptable.

In the event a problem develops with
the Mark 25 that cannot be resolved
through calibration, contact Martek
Instruments directly via telephone, fax,
or e-mail located at our website,
www.martekinstruments.com.

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