Extech Instruments 407303 User manual

User's Guide
Heavy Duty Conductivity / Temperature
Model 407303
Introduction
Congratulations on your purchase of Extech’s Conductivity/ Temperature Meter. This
meter offers a dual display for Conductivity and Temperature, a Conductivity Cell
calibration adjustment, temperature compensation, and a RS-232 PC Interface. This meter
is shipped fully tested and calibrated and with proper use will provide years of reliable
service.
99 Washington Street
Melrose, MA 02176
Phone [phone]
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
Back to the Extech 407303 Product Page

407303 V3.1 01/062
Specifications
Circuit Custom LSI microprocessor circuit
Display Dual function 2000 count LCD with contrast adjust
Measurement units Conductivity in Siemens (µS and mS); Temperature in oC/oF
Data hold Freezes displayed value
Sensor Structure Remote Conductivity Sensor: 1K Carbon rod type
Temperature sensor: Precision thermistor
Temperature
compensation adjust 0 to 5% per °C over the range of 32 to 140°F (0 to 60°C)
Record/Recall Record the Min/Max/Avg readings for later recall
Auto Power OFF Automatic power off after 10 minutes
PC Interface RS 232 serial data output
Operating conditions Temperature: 32°F to 122°F (0°C to 50°C); < 80% R.H.
Power Supply 9V battery
Power Consumption Approx. 10 mA DC
Weight 17 oz. (482 g) including batteries & probe
Dimensions Main instrument: 7.1 x 2.8 x 1.3" (180 x 72 x 32 mm)
Probe: 0.87" (22 mm) diameter
Measurement Range Resolution Accuracy
0.1 to 199.9 µS 0.1 µS
0.2 to 1.999 mS 0.001 mS
Conductivity
2 to 19.99 mS 0.01 mS
±(3% + 1d)
FULL SCALE
Temperature 32 to 140°F (0 to 60 °C) 0.1°F (0.1°C) ±1.5 °F (0.8 °C)
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

407303 V3.1 01/063
Meter Description
1. Sensor input plug – The plug is keyed so that it can only be inserted one way into the
sensor jack at top of meter
2. RS-232 PC Interface jack – For use with Model 407001 Data acquisition software and
interface cable kit
3. LCD Display indicates Conductivity and Temperature, unit of measure, and other user
alert symbols discussed in this manual
4. Push-buttons:
•POWER – Press to turn the meter ON or OFF
•HOLD – Press to freeze the displayed reading
•C/F – Press to select the temperature unit of measure
•RECORD – Press to begin tracking the MIN/MAX readings
•RECALL – Press to retrieve the MIN/MAX readings
•FACTOR ADJUST – Used with the TEMP button for temperature compensation
•RANGE – Slide switch to manually select the measurement range
•TEMP – Temperature coefficient compensation button
5. Battery compartment (rear) – Remove protective holster to access the compartment
6. LCD contrast adjustment dial – Adjust to desired view setting
7. Sensor top – Conductivity and Temperature sensor reside in sensor top
8. Rubber protective holster – Remove holster to access rear battery compartment
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407303 V3.1 01/064
Operation
Connecting the Sensor
1. Remove the protective sheath from the sensor tip before use. Retain the sheath for
sensor storage.
2. The sensor connects to the input jack at the top of the meter. The sensor jack is keyed,
thereby allowing the sensor plug to be inserted from only one direction. Line up the
plug with the jack before firmly inserting the sensor. Avoid undue force; forcing the
sensor into the jack may bend the pins in the sensor plug.
Powering the meter
1. Press the POWER button to turn the meter ON or OFF. If the meter does not switch on
when the POWER button is pressed, check the battery. Refer to the battery installation
and replacement section later in this manual.
2. This meter is equipped with an Automatic Power OFF feature. To conserve battery
energy, the meter shuts off after 10 minutes. To defeat this feature, press the
RECORD button to access the Record/Recall mode. In the Record/Recall mode, the
meter will remain on until the user turns it off or until the battery weakens.
LCD Contrast Adjustment
It may be necessary to adjust the display contrast due to a change in viewing angle or
voltage drift. Use the LCD Contrast adjustment wheel located on the right side of the meter
to set the preferred contrast.
Taking Measurements and using the RANGE select slide switch
1. Insert the sensor tip into the solution under test.
2. The conductivity and temperature readings will appear on the LCD. Conductivity
measurements appear at the center of the LCD. Temperature readings appear on the
bottom of the LCD in smaller digits.
3. Allow time for the measurements to stabilize. The LCD display digits will settle after a
short stabilization period.
4. If dashes appear on the top of the LCD measurement area, the reading is over range.
Slide the RANGE select switch to a higher range. If dashes appear on the bottom of
the measurement display area, the reading is under range. Slide the RANGE switch to
a lower range.
Selecting oC/oF units of measure
Press the oC/oF button to select the Temperature unit of measure. The display will reflect
the currently selected unit of measure.
Temperature Compensation using the FACTOR ADJ and TEMP buttons
This meter has a user adjustable temperature compensation feature that accommodates a
change in conductivity due to a change in solution temperature. The default compensation
is 2% and applies to most common standard salt solutions. Other solutions have known
temperature coefficients and the temperature adjustment allows the user to set it to match
the solution. To change the coefficient:
1. Set the meter to the 200µS range via the RANGE slide switch
2. Press the TEMP button
3. Press the Factor Adjust button to select the desired compensation factor (in increments
of 0.1% per degree C). The display will show the factor as it is adjusted.
4. Once the desired factor is set, press the TEMP button.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

407303 V3.1 01/065
Data Hold
To freeze the LCD display, press the HOLD button. The 'DH' display icon will appear on
the LCD when the meter is in the Data Hold mode. Press HOLD again to return to normal
operation (the 'DH' icon will switch off).
MIN/MAX/AVG Record/Recall Mode
1. To begin capturing the Minimum (MIN), Maximum (MAX), and Average (AVG)
Conductivity and Temperature values, press the RECORD button (REC will appear on
the LCD).
2. To recall the MAX reading press the RECALL button. The MAX display icon will appear
and the measurement display areas will indicate the highest reading encountered since
the RECORD button was pressed.
3. Press the RECALL button again to view the MIN reading.
4. Press the RECALL button again to view the AVG reading.
5. Press the RECORD button to exit and return to normal operation. The REC, MAX,
MIN, and AVG icons should be off when the meter has exited the MIN/MAX/AVG
Record/Recall mode.
Conductivity Calibration
1. Keep the battery connected to the meter, but remove it
from the battery compartment..
2. Prepare a standard conductivity solution of one or all of
the following: 200uS, 2.000mS and 20.00mS.
3. Place the probe into the calibration solution and adjust
the corresponding potentiometer in the battery
compartment until the meter reads the value of the
standard solution. Other VR potentiometers located in
the battery compartment should not be adjusted.
VR3 200uS
VR4 2.000mS
VR6 20.00mS
Sensor Care
Sensor Storage
On sheathed cells, replace the sheath when storing. For non-sheathed versions, soak the
sensor tip in de-ionized water in storage.
Sensor Cleaning
After each use, the sensor tip should be rinsed with de-ionized water. If solids build up
inside the sensor, carefully remove them with a cotton swab soaked in solvent. However,
do not touch the metal parts inside the sensor.

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Support line [phone]
Technical support: Extension 200; E-mail: [email protected]
Repair & Returns: Extension 210; E-mail: [e-mail]
Product specifications subject to change without notice
For the latest version of this User’s Guide, Software updates, and other
up-to-the-minute product information, visit our website: www.extech.com
Extech Instruments Corporation, 285 Bear Hill Rd., Waltham, MA 02451
RS-232 PC Interface
This meter is equipped with an RS-232 PC Interface jack. The jack is located at the top of
the meter next to the sensor input jack. The interface is intended for use with the data
acquisition software and hardware kit. For more information contact Extech or refer to the
Software User Manual.
Battery Replacement
The low battery indicator LBT appears on the LCD when the battery runs low. To replace
the battery:
1. Remove the meter's rubber protective cover to access the rear battery compartment.
2. Pry open the battery compartment cover using a small coin or screwdriver.
3. Replace the 9V battery and attach the compartment cover and protective holster.
Warranty
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com