Omega CDTX-90 User Manual

Conductivity/Resistivity

62.50 uS/cm

25.0°C

User’s Guide

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CDTX-90 Series

Conductivity/Resistivity Transmitters

OMEGAnet

®

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page 2

It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that
apply. OMEGA is constantly pursuing certification of its products to the European New Approach
Directives. OMEGA will add the CE mark to every appropriate device upon certification.

The information contained in this document is believed to be correct, but OMEGA Engineering, Inc. accepts
no liability for any errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, patient-connected applications.

Omega CDTX-90 Series Conductivity/Resistivity Transmitter

CAUTION!

• Remove power to unit before wiring
input and output connections.

• Follow instructions carefully to avoid
personal injury.

1. Installation

CDTX-90 Series transmitters are available in two styles: panel mount and field mount. The panel mount is supplied with the
necessary hardware to install the transmitter. This manual includes complete panel mounting instructions.
Field mounting requires a separate mounting kit. The FP90UM Universal kit enables the transmitter to be installed virtually
anywhere. Detailed instructions for field installation options are included with the FP90UM Universal kit.

1.1 Panel Installation

1. The panel mount transmitter is designed for installation using a 1/4 DIN Punch. For manual panel cutout, an adhesive
template is provided as an installation guide. Recommended clearance on all sides between instruments is 1 inch.

2. Place gasket on instrument, and install in panel.

3. Slide mounting bracket over back of instrument until quick-clips snap into latches on side of instrument.

4. To remove, secure instrument temporarily with tape from front or grip from rear of instrument. DO NOT RELEASE.
Press quick-clips outward and remove.

82 mm
(3.23 in.)

96 mm

(3.8 in.)

FRONT VIEW

Field Mount &

Panel Mount

96 mm
(3.8 in.)

106 mm
(4.18 in.)

SIDE VIEW

Field Mount

Contents

1. Installation

2. Specifications

3. Electrical Connections

4. Menu Functions

41 mm

)

(1.6 in.

SIDE VIEW

Panel Mount

Optional
Rear
Cover

56 mm
(2.2 in.)

97 mm

(3.8 in.)

92 mm
(3.6 in.)

gasket

latch

Panel Mount
Installation Detail

panel

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3

terminals

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A
L

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5

+

t
u
p

t
u

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quick-clips

Conductivity/Resistivity

62.50 uS/cm

25.0°C

mounting

bracket

ENTER

2. Specifications

General

Compatible electrodes: Omega CDCE-90 Series Standard and

Certified Series Conductivity/Resistivity Electrodes
Accuracy: ±2% of reading
Enclosure:

• Rating: NEMA 4X/IP65 front

• Case: PBT

• Panel case gasket: Neoprene

• Window: Polyurethane coated polycarbonate

• Keypad: Sealed 4-key silicone rubber

• Weight: Approx. 325g (12 oz.)
Display:

• Alphanumeric 2 x 16 LCD

• Contrast: User selected, 5 levels

• Update rate: 1.8 seconds

Electrical

• Power: 12 to 24 VDC ±10%, regulated, 80 mA max.

Sensor input range:

• Conductivity: 0.055 to 400,000 µS

• Resistivity: 10 KΩ to 18.2 MΩ
( Measurements from 10 MΩ to 18 MΩ (0.055 µS to 0.1 µS) must
be performed in solution temperatures from 20 °C to 100 °C. )

• TDS: 0.023 to 200,000 ppm

• Temperature: PT 1000, -25 to 120°C (-13 to 248°F)
Current output:

•4 to 20 mA, isolated, fully adjustable and reversible

• Max loop impedance: 50 Ω max. @ 12 V

325 Ω max. @ 18 V
600 Ω max. @ 24 V

• Update rate: 200 mS

• Accuracy: ±0.03 mA @ 25°C, 24 V
Relay outputs
(CDTX-90-2 includes 2 mechanical SPDT contacts):

• Maximum voltage rating:
5 A @ 30 VDC, or 5 A @ 250 VAC, resistive load

• Programmable for:

• High or Low setpoint with adjustable hysteresis

• Pulse operation (max. rate 400 pulses/min)

Open-collector output, optically isolated:

• 50 mA max. sink, 30 VDC maximum pull-up voltage.

• Programmable for:

• High or Low setpoint with adjustable hysteresis

• Pulse operation (max. rate 400 pulses/min)

Environmental

• Operating temperature: -10 to 70°C (14 to 158°F)

• Storage temperature: -15 to 80°C (5 to 176°F)

• Relative humidity: 0 to 95%, non-condensing

• Maximum altitude: 2000 m (6562 ft)

• Insulation category: II

• Pollution degree: 2

Standards and Approvals

• CSA, CE, UL listed

• Immunity: EN50082-2

• Emissions: EN55011

• Safety: EN61010

• Manufactured under ISO 9001 and ISO 14001

• U.S.A. Patent # 5,708,363

page 3

3. Electrical Connections

Sensor Selection

Select the sensor with a range closest to your process minimum and
maximum values.

• CDCE-90-001 (0.01 cell): 0.055 to 100 µS (10 kΩ to 18 MΩ)
Use the CDCE-90-001 for all resistivity requirements

• CDCE-90-01 (0.1 cell): 1 to 1000 µS

• CDCE-90-1 (1.0 cell): 10 to 10,000 µS

• CDCE-90-10 (10.0 cell): 100 to 200,000 µS

• CDCE-90-20 (20.0 cell): 200 to 400,000 µS

Ultra-

Pure

CDCE-90-001

Sensor Models

0.055 1 10 100 200 1,000 10,000 200,000 400,000

(18 MΩ)

Rinse

Pure

CDCE-90-01

CDCE-90-10

CDCE-90-1

(10 kΩ)

CDCE-90 Series Sensor Ranges

CDCE-90-20

Conductivity Range (µS)

Wiring Tips:

• Do not route sensor cable in conduit containing AC power
wiring. Electrical noise may interfere with sensor signal.

CDTX-90

Conductivity/Resistivity

62.50 uS/cm

25.0°C

≤ 100 ft. (30 m)

• Routing sensor cable in grounded metal conduit will help
prevent electrical noise and mechanical damage.

ENTER

• Seal cable entry points to prevent moisture damage.

• Only one wire should be inserted into a terminal. Splice
double wires outside the terminal.

• Sensor cable may not be extended over 100 ft.

Caution: Failure to fully open terminal jaws before removing wire may permanently damage instrument.

Wiring Procedure

1. Remove 0.5 - 0.625 in. (13-16 mm) of insulation from wire end.

2. Press the orange terminal lever downward with a small screwdriver to open terminal jaws.

3. Insert exposed (non-insulated) wire end in terminal hole until it bottoms out.

4. Release orange terminal lever to secure wire in place. Gently pull on each wire to ensure a good connection.

Wiring Removal Procedure

1. Press the orange terminal lever downward with a small screwdriver to open terminal jaws.

2. When fully open, remove wire from terminal.

3.1 Sensor Connections

CDTX-90-1 Terminals

2
1

Shield (Sensor Gnd)

10

Black (Iso Gnd)

9

White (Temp In)

8

Red (Signal In)

7

CDTX-90-2 Terminals

Shield (Sensor Gnd)

14

Black (Iso Gnd)

13

White (Temp In)

12

Red (Signal In)

11

CDTX-90-3 Terminals

Shield (Sensor Gnd)

14

Black (Iso Gnd)

13

White (Temp In)

12

Red (Signal In)

11

CDCE-90 Series Standard and Certified Cells

page 4

CDTX-90-1 Terminal connections

Terminals 3 and 4: Loop Power

12-24 VDC ±10% system power
and current loop output.
Max. loop impedance:
50 Ω max. @ 12 V
325 Ω max. @ 18 V
600 Ω max. @ 24 V

Terminals 7-10: Sensor input
7 is conductivity input
8 is temperature input
9 is the isolated signal ground
10 is the sensor earth ground

System Pwr

4

Loop -

System Pwr

3

Loop +

AUX

2

Power -

AUX
Power +

1

Internal open-collector

Terminals 1-2: Auxiliary power

output circuit

Provides DC power to measurement
circuit. Required for all CDTX-90
systems.

Isolation

Terminals 5-6: Open-collector Output

•A transistor output, programmable (see CALIBRATE menu) as High or Low setpoint with
adjustable hysteresis and proportional pulse (to 400 pulses per minute maximum).

• May be disabled (Off) if not used.

CDTX-90-1 System Power/Loop Connections

6

5

Output -

Output +

S

D

15Ω

10

9

8

7

Output --

Output +

Sensr Gnd
(SHIELD)

Iso. Gnd
(BLACK)

Temp. IN
(WHITE)

Signal IN
(RED)

Stand-alone application, no current loop used

Transmitter

Ter minals

Sys. Pwr.
Loop -

Sys. Pwr.
Loop +

AUX
Power -

AUX
Power +

4
3
2
1

Power Supply
DC 12 - 24 V

Power

-

Supply
Power

Supply

+

Connection to a PLC/Recorder, separate supply

Transmitter

Ter minals

Sys. Pwr.
Loop -

Sys. Pwr.
Loop +

AUX
Power -

AUX
Power +

4
3
2
1

DC 12 - 24 V

Power

-

Supply
Power

Supply

+

PLC or Recorder

Loop Input

-

4-20 mA in
Loop Input

+

4-20 mA in

AUX power required for all CDTX-90 systems.

Connection to a PLC with built-in power supply

Transmitter

Ter minals

Sys. Pwr.
Loop -

Sys. Pwr.
Loop +

AUX
Power -

AUX
Power +

4
3
2
1

Internal PLC
Connection

PLC

-

+

-

+

Ter minals

Power Supply
Ground

Power
Supply

Loop Input
4-20 mA

Loop Input
4-20 mA

Example: Two transmitters connected to PLC/Recorder

Transmitter 1

Sys. Pwr.
Loop -

Sys. Pwr.
Loop +

AUX
Power -

AUX
Power +

Transmitter 2

Sys. Pwr.
Loop -

Sys. Pwr.
Loop +

AUX
Power -

AUX
Power +

4
3
2
1

4
3
2
1

with separate power supply

DC 12 - 24 V

Power
Supply

Power
Supply

PLC or Recorder

Channel 1
4-20 mA in

-

Channel 1

+

4-20 mA in
Channel 2

-

4-20 mA in
Channel 2

+

4-20 mA in

page 5

CDTX-90-2 Terminal Connections

Terminals 3 and 4: Loop Power

12-24 VDC ±10% system power
and current loop output.
Max. loop impedance:
50 Ω max. @ 12 V
325 Ω max. @ 18 V
600 Ω max. @ 24 V

System Pwr

4

Loop ­System Pwr

3

Loop +
AUX

2

Power ­AUX

Power +

1

10

9
8
7
6
5

Relay 2
(NO)

Relay 2
(COM)

Relay 2
(NC)

Relay 1
(NO)

Relay 1
(COM)

Relay 1
(NC)

Terminals 11-14: Sensor input
11 is conductivity input
12 is temperature input
13 is the isolated signal ground
14 is the sensor earth ground

Sensr Gnd

14

(SHIELD)
Iso. Gnd

13

(BLACK)
Temp. IN

12

(WHITE)
Signal IN

(RED)

11

Terminals 1-2: Auxiliary power

Provides DC power to sensor.

Terminals 5-10: Relay Outputs

• Two SPDT mechanical relays, programmable as:

Required for all CDTX-90 systems.

CDTX-90-2 System Power/Loop Connections

Stand-alone application, no current loop used

Transmitter

Power Supply

Terminals

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

4
3
2
1

DC 12 - 24 V

Power

-

Supply
Power

+

Supply

Connection to a PLC/Recorder, separate supply

Transmitter

Terminals

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

4
3
2
1

DC 12 - 24 V

Power

-

Supply
Power

+

Supply

PLC or Recorder

Loop Input

-

4-20 mA in
Loop Input

+

4-20 mA in

AUX required for all CDTX-90 systems.

• High or Low setpoint with adjustable hysteresis.

• proportional Pulse (400 pulses per minute maximum).

• May be disabled (Off) if not used.

Connection to a PLC with built-in power supply

Transmitter

-

Terminals

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

4
3
2
1

Internal PLC
Connection

Example: Two transmitters connected to PLC/Recorder

Transmitter 1

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

4
3
2
1

with separate power supply

Transmitter 2

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

4
3
2
1

+

-

+

DC 12 - 24 V

-

+

PLC or Recorder

-

+

-

+

PLC

Te rm inals

Power Supply
Ground
Power
Supply
Loop Input
4-20 mA
Loop Input
4-20 mA

Power
Supply
Power
Supply

Channel 1
4-20 mA in
Channel 1
4-20 mA in

Channel 2
4-20 mA in
Channel 2
4-20 mA in

page 6

CDTX-90-3 Terminal Connections

Terminals 3-6: Loop Power

12-24 VDC ±10% system power and current loop output.
Max. loop impedance:
50 Ω max. @ 12 V
325 Ω max. @ 18 V
600 Ω max. @ 24 V

Loop 2-

6

Loop 2+

5

10

Output 2-

Terminals 11-14: Sensor input
11 is conductivity input
12 is temperature input
13 is the isolated signal ground
14 is the sensor earth ground

System Pwr

4

Loop ­System Pwr

3

Loop +
AUX

2

Power ­AUX

1

Power +

9
8

7

Terminals 7-10: Open-collector Outputs

•Two transistor outputs, programmable

Terminals 1-2: Auxiliary power

Provides DC power to measurement
circuit. Required for all CDTX-90
systems.

as:

• High or Low setpoint with adjustable
hysteresis

• proportional pulse (to 400 pulses per
minute maximum)

• May be disabled (Off) if not used

CDTX-90-3 System Power/Loop Connections

Stand-alone application, no current loop used

Transmitter

Terminals

Loop2-

Loop2+

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

6

NC
NC

5
4
3
2
1

Connection to a PLC/Recorder, separate supply

Transmitter

Terminals

Loop2-

Loop2+

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

6
5
4
3
2
1

Power Supply
DC 12 - 24 V

Power

-

Supply
Power

+

Supply

DC 12 - 24 V

Power

-

Supply
Power

+

Supply

PLC or Recorder

Channel 2

-

4-20 mA in
Channel 2

+

4-20 mA in
Channel 1

-

4-20 mA in
Channel 1

+

4-20 mA in

AUX power required for all CDTX-90 systems.

Output 2+

Output 1-

Output 1+

Sensr Gnd

14

(SHIELD)
Iso. Gnd

13

(BLACK)
Temp. IN

12

(WHITE)
Signal IN

(RED)

11

Internal open-collector

output circuit

S

Isolation

D

15Ω

Outputs

1

Connection to a PLC with built-in power supply

Transmitter

Terminals

Loop2-

Loop2+

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

6
5
4
3
2
1

Internal PLC
Connection

PLC

Terminals

-

+

-

+

-

+

Power Supply
Ground
Power
Supply
Channel 2
4-20 mA in
Channel 2
4-20 mA in
Channel 1
4-20 mA in
Channel 1
4-20 mA in

Example: Two transmitters connected to PLC/Recorder

Loop2-

Loop2+

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +
AUX
Power ­AUX
Power +

Loop2-

Loop2+

Sys. Pwr.
Loop ­Sys. Pwr.
Loop +

Transmitter 1 Transmitter 2

AUX
Power ­AUX
Power +

6
5
4
3
2
1

6
5
4
3
2
1

with separate power supply

DC 12 - 24 V

Power

-

Supply
Power

+

Supply

PLC or Recorder

- Channel 4
+ Channel 4

- Channel 3
+ Channel 3

- Channel 2
+ Channel 2

- Channel 1
+ Channel 1

2

_

+

page 7

3.3 Relay and Open Collector Outputs

The Relay and Open Collector outputs can be used as a switch
that responds when the process value moves above or below a
setpoint, or they can be used to generate a pulsing signal with a
rate proportional to the process value.

• Low setpoint:
Output triggers when process is less than the setpoint.
The output will relax when the process moves above the setpoint
plus the hysteresis value.

• High setpoint:
Output triggers when process is greater than the setpoint.
The output will relax when the process moves below the setpoint
plus the hysteresis value.

Process

Hysteresis

Low Setpoint

Time

Relay energized

Relay relaxed

• Proportional Pulsing
The output will generate a 100 mS pulse at the rate defined by
settings in the CALIBRATE menu.

In the example below:

• The output will be 0 pulses/min. when value is less than 5 µ S.

• The output will be 50 pulses/min. when value is 7.5 µS.

• The output will be 100 when value is greater than 10 µS.

The starting point, endpoint and maximum pulse rate are
selectable in the CALIBRATE menu.

100 pulses

0 to 100 Pulses/min.

Open Collector Output Rate:

Pulse rate

0 pulses

Process

5

Starting point

High Setpoint

Hysteresis

Time

VIEW menu

• During normal operation, the transmitter displays the VIEW menu.

• When editing the CALIBRATE or OPTIONS menus, the transmitter will return to the VIEW menu
if no activity occurs for 10 minutes.

• To select a VIEW display, press the UP or DOWN arrow keys. The selections will scroll in a
continuous loop.

• Changing the VIEW display does not interrupt system operations.

• No key code is necessary to change display selection.

• Output settings cannot be edited from the VIEW menu.

CDTX-90 Series View Menu

Display Description

10

endpoint

Conductivity/Resistivity

62.50 uS/cm

25.0°C

ENTER

page 8

123.45 µS/cm
+67.89 ºC

Monitor the Conductivity and Temperature values from the sensor.
This is the permanent display.

The VIEW displays below are temporary. The permanent display will return after 10 minutes

Loop Output:

13.75 mA

Last CAL:

06-30-01

Monitor the Loop Current output.

Check the Last Calibration date.

CDTX-90 Series Editing Procedure:

Step 1. Press and hold ENTER key:

• 2 seconds to select the CALIBRATE menu.

• 5 seconds to select the OPTIONS menu.

Step 2. The Key Code is UP-UP-UP-DOWN keys in sequence.

• After entering the Key Code, the display will show the first item in the selected menu.

Step 3. Scroll menu with UP or DOWN arrow keys.
Step 4. Press RIGHT ARROW key to select menu item to be edited.

• The first display element will begin flashing.

Step 5. Press UP or DOWN keys to edit the flashing element.

• RIGHT ARROW key advances the flashing element.

Step 6. Press ENTER key to save the new setting and return to Step 3.

Notes on Step 1:

• The View Menu is normally displayed.

• The CALIBRATE and OPTIONS menus require a KEY CODE.

Press &
hold for
access:

VIEW

ENTER

Notes on Step 2:

If no key is pressed for 5 minutes while display is showing "Enter
Key Code", the display will return to the VIEW menu.

2s 5s

CALIBRATE

OPTIONS

Notes on Steps 3 and 4:

• Refer to pages 8-13 for complete listing of menu items and their use.

• From the Step 3 display, pressing the UP and DOWN keys simultaneously will
return the display to the VIEW menu.

• If no key is pressed for 10 minutes, display will also return to the VIEW menu.

Step 3: Finished Editing?

Press the UP and DOWN keys simultaneously after
saving the last setting to return to normal operation.

CALIBRATE: ----

Enter Key Code

CALIBRATE: *---

Enter Key Code

CALIBRATE: **--

Enter Key Code

CALIBRATE: ***-

Enter Key Code

Cell Constant:

Standard >

Cell Constant:

Output Setpnt:

20.0 uS >

First item in
CALIBRATE menu

Standard >

Step 3

Step 4

Notes on Steps 5 and 6:

• All output functions remain active during editing.

• Only the flashing element can be edited.

• RIGHT ARROW key advances the flashing element in a continuous loop.

• Edited value is effective immediately after pressing ENTER key.

• If no key is pressed for 10 minutes unit will restore the last saved value and return to step 3.

• Step 6 (pressing ENTER key) always returns you to Step 3.

• Repeat steps 3-6 until all editing is completed.

Output Setpnt:

Step 5: Made an Error?

Press the UP and DOWN keys simultaneously
while any element is flashing. This will recall the
last saved value of the item being edited and
return you to Step 3.

2

0.00 uS

Output Setpnt:

1

0.00 uS

Output Setpnt:

10

Step 6

Output Setpnt:

19.00 uS >

Step 5

.00 uS

Output Setpnt:

9

1

.00 uS

ENTER

Output Setpnt:

Saving

page 9

CDTX-90-1 Calibrate Menu

Display

(Factory settings shown)

Description

Cell Constant:

Standard >

Cell: Standard

1>

Cell: Custom

1.0000 >

Cond Units:

uS >

PPM Factor:

2.00 >

Set:

Temperature >

Set:

Conductivity >

Select CUSTOM only if you are connecting a certified conductivity sensor. Select
STANDARD for all other systems.

For STANDARD sensors: Select from these options: 0.01, 0.1, 1.0, 10.0 or 20.0.

For CUSTOM sensors: Enter the precise cell constant from the certificate provided with your
sensor, or from the information label on the sensor.

Select from the following options: µS, mS, kΩ, MΩ, PPM

If the Units selection is PPM, you can set the ratio of Total Dissolved Solids to µS. See page
15 for additional information. The TDS factor can only be set in PPM.

Adjust the temperature of the system based on an accurate external reference.

For use with STANDARD sensors: Perform this single-point wet calibration for most accurate
results. Not required for CUSTOM sensors except for periodic system accuracy confirmation.
Enter all zeroes to restore factory calibration to TEMP and COND settings.

Loop Source:

Cond >

Loop Range: uS

0.0000

→→

→ 100.000 >

→→

Output Source:

Cond >

Output Mode:

Low >

Output Setpnt:

10.0000 uS >

Output Hys:

0.5000 uS >

Output Rng: uS

10.0000

→→

→ 40.0000 >

→→

Select the input source to be associated with the current loop output: Conductivity or
Temperature.

Select the minimum and maximum values for the current loop output.
Be sure to modify this setting if you change the Cond. Units.

Select the source for the Open Collector output: Conductivity or Temperature

Select the mode of operation for the Open Collector output.
Options available are High, Low or proportional Pulse.
The signal may be disabled (Off) if not in use.

In Low or High Mode, this Open Collector output will be activated when the process reaches
this value. Be sure to modify this setting if you change the Cond. Units.

The Open Collector output will be deactivated at Setpoint ± Hysteresis, depending on High or
Low Setpoint selection. (See details in section 3.3.)

In Pulse mode, set the process values where the proportional pulse will start and where it will
reach the maximum rate. Be sure to modify this setting if you change the Cond. Units.

Output PlsRate:

120 Pulses/Min >

Last CAL:

06-30-01 >

page 10

In Pulse mode, set the maximum rate for the proportional Pulse output. The CDTX-90 will
accept any value from 0 to 400.

Use this “note pad” to record important dates, such as annual recertification or scheduled
maintenance.

CDTX-90-1 Options Menu

Display

(Factory settings shown)

Contrast:

3>

Cond Decimal:

****.* >

Averaging

Off >

Loop Adjust:

4.00 mA >

Loop Adjust:

20.00 mA >

Temp Display:

ºC>

Temperature
Comp %: 2.00 >

Description

Adjust the LCD contrast for best viewing. A setting of 1 is lower contrast, 5 is higher.
In general, select lower contrast if the display is in warmer ambient surroundings.

Set the decimal to the best resolution for your application. The display will auto­matically scale down to this restriction. Select *****., ****.*, ***.** **.*** or *.****

OFF provides the most instantaneous response to process changes. Select
LOW (4 sec) or HIGH (8 sec) averaging if your process experiences frequent or
extreme fluctuations.

Adjust the minimum and maximum current output. The display value represents
the precise current output. Adjustment limits:

• 3.80 mA < 4.00 mA > 5.00 mA

• 19.00 mA < 20.00 mA > 21.00 ma
Use this setting to match the system output to any external device.

Select ºC or ºF

Set the percent change in Conductivity caused by a 1ºC change in temperature.
May be from 0.00 to 10.00.

Output Active:

Low >

Test Loop:

Test Output:

Active HIGH: This setting is used to turn a device (pump, valve) ON at the
setpoint.
Active LOW: This setting is used to turn a device OFF at the setpoint.

Press UP and DOWN keys to manually order any output current value from 3.6
mA to 21.00 mA to test the output loop.

>

Press UP and DOWN keys to manually toggle the Open Collector output state.

>

page 11

CDTX-90-2 Calibrate Menu

Display

(Factory settings shown)

Cell Constant:

Standard >

Description

Select CUSTOM only if you are connecting a certified conductivity sensor. Select
STANDARD for all other systems.

Cell: Standard

1>

Cell: Custom

1.0000 >

Cond Units:

µS>

PPM Factor:

2.00 >

Set:

Temperature >

Set:

Conductivity >

Loop Source:

Cond >

For STANDARD sensors: Select from these options: 0.01, 0.1, 1.0, 10.0 or 20.0.

For CUSTOM sensors: Enter the precise cell constant from the certificate provided with
your sensor, or from the information label on the sensor.

Select from these options: µS, mS, kΩ, MΩ, PPM

If the Units selection is PPM, set the ratio of Total Dissolved Solids to µS. The maximum
allowable is 3 µS = 1 PPM. The TDS factor can only be set in PPM.

Adjust the temperature of the system based on an accurate external reference.

When using a h STANDARD sensor perform this single-point wet calibration for best
accuracy. Not required for CUSTOM sensors except for periodic calibration checks.

Select the input (Conductivity or Temperature) source to be associated with the current
loop output:

Loop Range: µS

0.0000

→→

→ 100.000 >

→→

Relay1 Source:

Cond >

Relay1 Mode:

Low >

Relay1 Setpnt:

10.0000 µS>

Relay1 Hys: µS

0.5000 >

Relay1 Rng: µS

10.0000

→→

→ 40.0000 >

→→

Relay1 PlsRate:
120 Pulses/Min >

Select the minimum and maximum values for the current loop output.
Be sure to modify this setting if you change the Cond. Units.

Select the source (Conductivity or Temperature) for this relay output:

Select the mode of operation for the relay.
Options available are High, Low or proportional Pulse.
The relay may be disabled (Off) if not in use.

In Low or High Mode, the relay will be activated when the process reaches this value. Be
sure to modify this setting if you change the Cond. Units.

The relay will be deactivated at Setpoint ± Hysteresis, depending on High or Low Setpoint
selection.

In Pulse mode, set the process values where the proportional pulse will start and where it
will reach the maximum rate. Be sure to modify this setting if you change the Cond. Units.

In Pulse mode, set the maximum rate for the proportional Pulse. The transmitter will
accept any value from 0 to 400.

page 12

Last CAL:

06-30-01 >

Use this “note pad” to record important dates, such as annual recertification or scheduled
maintenance.

CDTX-90-2 Options Menu

Display

(Factory settings shown)

Contrast:

3>

Cond Decimal:

****.* >

Averaging:

Off >

Loop Adjust:

4.00 mA >

Loop Adjust:

20.00 mA >

Temp Display:

ºC>

Temperature
Comp %: 2.00 >

Description

Adjust the LCD contrast for best viewing. A setting of 1 is lower contrast, 5 is higher. In
general, select lower contrast if the display is in warmer ambient surroundings.

Set the decimal to the best resolution for your application. The display will automatically
scale down to this restriction. Select *****., ****.*, ***.** **.*** or *.****

OFF provides the most instantaneous response to process changes. Select LOW (4 sec)
or HIGH (8 sec) averaging if your process experiences frequent or extreme fluctuations.

Adjust the minimum and maximum current output. The display value represents the
precise current output. Adjustment limits:

• 3.80 mA < 4.00 mA > 5.00 mA

• 19.00 mA < 20.00 mA > 21.00 ma
Use this setting to match the system output to any external device.

Select ºC or ºF.

Set the percent change in Conductivity caused by a 1ºC change in temperature. May be
from 0.00 to 10.00.

Test Loop:

Test Relay1:

Press UP and DOWN keys to manually order any output current value from 3.6 mA to

21.00 mA to test the output loop.

>

Press UP and DOWN keys to manually toggle the relay state.

>

page 13

CDTX-90-3 Calibrate Menu

Display

(Factory settings shown)

Description

Cell Constant:

Standard >

Cell: Standard

1>

Cell: Custom

1.0000 >

Cond Units:

uS >

PPM Factor:

2.00 >

Set:

Temperature >

Set:

Conductivity >

Select CUSTOM only if you are connecting a certified conductivity sensor. Select
STANDARD for all other systems.

For STANDARD sensors: Select from these options: 0.01, 0.1, 1.0, 10.0 or 20.0.

For CUSTOM sensors: Enter the precise cell constant from the certificate provided with your
sensor, or from the information label on the sensor.

Select from the following options: µS, mS, kΩ, MΩ, PPM

If the Units selection is PPM, you can set the ratio of Total Dissolved Solids to µS. See
section 3 of this manual for additional information. The TDS factor can only be set in PPM.

Adjust the temperature of the system based on an accurate external reference.

For use with STANDARD sensors: Perform this single-point wet calibration for most accurate
results. Not required for CUSTOM sensors except for periodic system accuracy confirmation.
Enter all zeroes to restore factory calibration to TEMP and COND settings.

Loop1 Source:

Cond >

Loop1 Range: uS

0.0000

→→

→ 100.000 >

→→

Output Source:

Cond >

Output1 Mode:

Low >

Output1 Setpnt:

10.0000 uS >

Output1 Hys:

0.5000 uS >

Output1 Rng: uS

10.0000

→→

→ 40.0000 >

→→

Select the input source to be associated with the current loop output: Conductivity or
Temperature

Select the minimum and maximum values for the current loop output.
Be sure to modify this setting if you change the Cond. Units.

Select the source for the Open Collector output: Conductivity or Temperature

Select the mode of operation for the Open Collector output.
Options available are High, Low or proportional Pulse.
The signal may be disabled (Off) if not in use.

In Low or High Mode, this Open Collector output will be activated when the process reaches
this value. Be sure to modify this setting if you change the Cond. Units.

The Open Collector output will be deactivated at Setpoint ± Hysteresis, depending on High or
Low Setpoint selection. (See details on page 4.)

In Pulse mode, set the process values where the proportional pulse will start and where it will
reach the maximum rate. Be sure to modify this setting if you change the Cond. Units.

Output1 PlsRate:

120 Pulses/Min >

Last CAL:

06-30-01 >

Settings will repeat for Loop 2 and Output 2.

page 14

In Pulse mode, set the maximum rate for the proportional Pulse output. The transmitter will
accept any value from 0 to 400.

Use this “note pad” to record important dates, such as annual recertification or scheduled
maintenance.

CDTX-90-3 Options Menu

Display

(Factory settings shown)

Contrast:

3>

Cond Decimal:

****.* >

Averaging

Off >

Loop1 Adjust:

4.00 mA >

Loop1 Adjust:

20.00 mA >

Temp Display:

ºC>

Temperature
Comp %: 2.00 >

Description

Adjust the LCD contrast for best viewing. A setting of 1 is lower contrast, 5 is higher.
In general, select lower contrast if the display is in warmer ambient surroundings.

Set the decimal to the best resolution for your application. The display will
automatically scale down to this restriction. Select *****., ****.*, ***.** **.*** or
*.****

OFF provides the most instantaneous response to process changes. Select
LOW (4 sec) or HIGH (8 sec) averaging if your process experiences frequent or
extreme fluctuations.

Adjust the minimum and maximum current output. The display value represents
the precise current output. Adjustment limits:

• 3.80 mA < 4.00 mA > 5.00 mA

• 19.00 mA < 20.00 mA > 21.00 ma
Use this setting to match the system output to any external device.

Select ºC or ºF

Set the percent change in Conductivity caused by a 1ºC change in temperature.
May be from 0.00 to 10.00.

Output1 Active:

Low >

Test Loop 1:

Test Output 1:

Active HIGH: This setting is used to turn a device (pump, valve) ON at the
setpoint.
Active LOW: This setting is used to turn a device OFF at the setpoint.

Press UP and DOWN keys to manually order any output current value from

3.6 mA to 21.00 mA to test the output loop.

>

Press UP and DOWN keys to manually toggle the Open Collector output state.

>

Settings will repeat for Loop 2 and Output 2.

page 15

Calibration Procedure

1. Requirements

The CDTX-90 Transmitter is factory calibrated using simulated input signals. System calibration will reduce errors caused by
sensor wire lengths longer than the standard 15 ft. length. Wire lengths of 100 feet are acceptable; cable shield must be
maintained through cable splice. Calibration may be done by known solution value (A), or by resistance simulation (B).

A) Calibration with NIST Traceable Solutions:

When using NIST traceable standards, ensure the sensor and test solution are at the solution temperature specified on the test
solution label. Prevent contamination of the calibration solution. Thoroughly rinse the sensor in a small amount of test solution
before placing in any test solution for calibration purposes.

B) Optional Verification with Precision Resistors:

The use of precision resistors (±0.1%) connected to the rear "Temp In", "Signal IN", and "Iso Gnd" terminals in place of the
sensor, yields quick and accurate electronic instrument calibration. Calibration is completed as follows:

1) Select a standard cell constant based on desired range of operation.

2) Place a 1096 Ω (25°C) resistor between "Temp IN" and "Iso. Gnd" terminals as shown.
Note: Temperature simulation errors can adversely effect calibration: 3.85 per °C.

3) Calculate the required simulation resistor that represents a value within the selected
cell range. The formula for determining the required simulation resistance is:

Resistance =

Conductivity =

Sensor Cell

Desired conductivity (Siemens*) 0.000020 (Siemens*)

:

Sensor Cell :

Simulation resistance (Ω) 100,000 (Ω)

0.1 Cell

e.g.

0.1 Cell

e.g.

= 5,000 Ω or 5 KΩ

0.000001 Siemens*

=

or 1µS/cm

9
8
7

Iso. Gnd
(BLACK)

Temp. IN
(WHITE)

Signal IN
(RED)

(*Conversion: 1 µS = 1 X 10-6 Siemens or 0.000001 Siemens)

4) Place the calculated simulation resistance between the "Signal IN" and "Iso Gnd" terminals as shown.

5) Set temperature and set conductivity. (Optional: Reset to factory calibration by entering zero as the "Set Conductivity" value.)

2. Temperature Coefficient

Conductivity measurement is highly dependent on temperature.
Temperature dependence is expressed as the relative change per
°C, commonly known as percent/°C change from 25°C, or slope
of the solution.

3. Cool the sample solution close to the minimum process
temperature. Place sensor in the sample solution allowing
several minutes for stabilization. Record displayed
temperature and conductivity values in the spaces provided:

TC resistor

Simulation resistor

Slopes can very significantly depending on process solution type.
The factory default temperature compensation factor is 2.00%/°C.
Process solutions may require adjustment for maximum accuracy.
To determine the optimum temperature compensation factor for a
process:

1. Disable the temperature compensation % factor by entering

0.00.

2. Heat the sample solution close to the maximum process
temperature. Place sensor in the sample solution allowing
several minutes for stabilization. Access the VIEW menu
and record the displayed temperature and conductivity
values in the spaces provided:

Displayed temperature: T1 = _______ °C
Displayed conductivity: C1 = _______ °C

(Do not use this procedure for solutions from 0.055 µS to 0.1 µS
(10 MΩ to 18 MΩ). An internal pure water curve is used for these
ranges. The factory default setting of 2.00%/°C should be used.)

page 16

Displayed temperature: T2 = _______ °C
Displayed conductivity: C2 = _______ °C

(A 10% change in conductivity between steps 2 and 3 is
recommended.)

4. Substitute recorded readings (steps 2 and 3) into the
following formula:

TC Slope =

100 x (C1 - C2)

(C2 x (T1 - 25)) - (C1 x (T2 - 25))

Example: A sample solution has a conductivity of 205 µS
@ 48°C. After cooling the solution, the conductivity was
measured at 150 µS @ 23 °C. (C1 = 205, T1 = 48, C2 =
150, T2 = 23)
The TC is calculated as follows:

TC Slope =

(150 x (48 - 25)) - (205 x (23 - 25)) 3860

100 x (205 - 150) = 5500

=

1.42%/°C

Parts Per Million (PPM) Factor

This feature is only applicable when PPM display units are selected. The programmable PPM Factor is adjustable from 0.01 to

3.00 (factory default = 2.00). Determine the best PPM Factor for a process solution by calculating the solution's conductivity (µS)
and the percent of total dissolved solids (PPM).

PPM Factor =

TDS (PPM) =

Example: • Solution conductivity = 400 µS/cm

PPM Factor =

Troubleshooting

Display Condition Suggested SolutionsPossible Causes

"- - - -"

Value Must be less
than 3

Solution conductivity (µS)/cm
Total dissolved solids (PPM)

Solution conductivity (µS)/cm
PPM Factor

• TDS = 200 PPM (mg/L)

400 µS/cm
200 PPM

Display is over range. This may be a
normal condition if your process operates
at/near the limits of the sensor range.
kΩ or MΩ units selected & sensor is open.

The PPM factor must be a value from

0.00 to 3.00

= 2.00

Check sensor for correct range.
Check Decimal setting in OPTIONS menu.
Check Calibrate menu settings for incompatible
SOURCE and RANGE values.

Set a PPM value less than 3.

Value must be greater than 0

"Value must be
400 or less"

Display erratic, shows "0" or
"------" intermittently

"Too much Error
Check Sensor"

Technical notes

If a Current Loop is locked at 3.6 mA, the problem is related to the temperature circuit:
This occurs only if the CDTX-90 detects a resistance from the temperature sensor that is less than 250Ω or greater than 2800Ω.

• Check the sensor wiring for open/short or poor connections on white (TEMP IN) and black (ISO GND)wires.

• The PT1000 temperature device in the sensor is defective.

• The transmitter is defective.

Auxiliary Power (terminals 1 and 2) must ALWAYS be connected for the CDTX-90 to operate.

Custom cell constant cannot be set to 0

Pulse Rate cannot be greater than 400

Auxiliary Power not connected

Defective or dirty/coated sensor
Wiring error
Fluid conductivity too low
Defective temp element

Set cell constant to a value greater than 0

set a pulse rate value less than 400

Connect Auxiliary power

Clean or replace sensor
Check and correct wiring

Replace sensor

page 17

Notes

page 18

WARRANTY/DISCLAIMER

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a
period of 13 months from date of purchase. OMEGA’s WARRANTY adds an additional one (1) month
grace period to the normal one (1) year product warranty to cover handling and shipping time. This
ensures that OMEGA’s customers receive maximum coverage on each product.

If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service
Department will issue an Authorized Return (AR) number immediately upon phone or written request.
Upon examination by OMEGA, if the unit is found to be defective, it will be repaired or replaced at no
charge. OMEGA’s WARRANTY does not apply to defects resulting from any action of the purchaser,
including but not limited to mishandling, improper interfacing, operation outside of design limits,
improper repair, or unauthorized modification. This WARRANTY is VOID if the unit shows evidence of
having been tampered with or shows evidence of having been damaged as a result of excessive corrosion;
or current, heat, moisture or vibration; improper specification; misapplication; misuse or other operating
conditions outside of OMEGA’s control. Components which wear are not warranted, including but not
limited to contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any
damages that result from the use of its products in accordance with information provided
by OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by it
will be as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR
REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESS OR IMPLIED, EXCEPT THAT OF
TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF
LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of
OMEGA with respect to this order, whether based on contract, warranty, negligence,
indemnification, strict liability or otherwise, shall not exceed the purchase price of the
component upon which liability is based. In no event shall OMEGA be liable for
consequential, incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or
activity, medical application, used on humans, or misused in any way, OMEG A assumes no responsibility
as set forth in our basic WARRANTY / DISCLAIMER language, and, additionally, purchaser will indemnify
OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the
Product(s) in such a manner .

RETURN REQUESTS/INQUIRIES

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE
RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN
(AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID
PROCESSING DELAYS). The assigned AR number should then be marked on the outside of the return
package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent
breakage in transit.

FOR

WARRANTY RETURNS, please have the
following information available BEFORE
contacting OMEGA:

1. Purchase Order number under which the

product was PURCHASED,

2. Model and serial number of the product under

warranty, and

3. Repair instructions and/or specific problems

relative to the product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords
our customers the latest in technology and engineering.

OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2000 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,

reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the
prior written consent of OMEGA ENGINEERING, INC.

FOR NON-WARRANTY REPAIRS,

consult OMEGA
for current repair charges. Have the following
information available BEFORE contacting OMEGA:

1. Purchase Order number to cover the COST of

the repair,

2. Model and serial number of the product, and

3. Repair instructions and/or specific problems

relative to the product.

page 19

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Process Measurement and Control?

OMEGA…Of Course!

Shop online at www.omega.com

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