LaMotte DA-1-1929 User Manual

Multi-Range

Conductivity

Meter

CODE 1704

MODEL DA-LR

EPA

COMPLIANTCOMPLIANT

LaMOTTE COM PANY

Helping Peo ple Solve An a lyt i cal Challenges

PO Box 329 • Chestertown • Mary land • 21620 • USA

800-344-3100 • 410-778-3100 (Out side U.S.A.) • Fax [phone]

Visit us on the web at www.lamotte.com

SM

4/97

INTRODUCTION

The LaMotte Multi-Range Conductivity Meter is a portable, battery-operated
instrument with solid state circuitry. The meter accurately measures a wide
range of conductivity with a single probe. A conductivity reading measures the
capacity of a solution to conduct an electric current and is directly related to
the total ionic concentration of dissolved substances in the solution.

The instrument’s extensive capabilities range from checking the purity of
distilled water to use as a salinometer for monitoring the conductivity of sea
water. Other applications include checking air and water pollution, evaluating
electroplating baths, measuring soluble salts in soils, and monitoring industrial
and municipal water treatment operations.

This easy-to-use instrument has a rugged 3a” taut-band meter movement with
a mirrored scale that eliminates reading errors due to parallax. Other features
include a battery check circuit and manual temperature compensation from 0°C
to 100°C.

The conductivity meter is equipped with a range selector which monitors
conductivities from 0-10,000 micromhos/cm in four different ranges: 0-10;
0-100; 0-1000; and 0-10,000 micromhos/cm. A single conductivity probe on a
twelve foot cable is used to measure all four ranges. An optional
interchangeable probe is available with fifty feet of cable for measuring
conductivity profiles in deep water.

Should it be necessary to return the instrument for repair or servicing, pack the
instrument carefully in suitable container with adequate packing material. A
return authorization number must be obtained from LaMotte Company by
calling 1-800-344-3100. Attach a letter with the authorization number to the
shipping carton which describes the reason for the return. This valuable
information will enable the service department to make the required repairs
more efficiently.

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STANDARD CONDUCTIVITY SOLUTIONS

SIZE DESCRIPTION CODE

500 mL 74 micromhos/cm, 0.0005M KCl 6416-L
500 mL 718 micromhos/cm, 0.005M KCl 6417-L
500 mL 1413 micromhos/cm, 0.01M KCl 6354-L
500 mL 6668 micromhos/cm, 0.05M KCl 6418-L
500 mL 58640 micromhos/cm, 0.5M KCl 6419-L

REPLACING THE BATTERY

When the meter does not indicate greater than 80 micromhos in the “BAT.
CK.” position, replace the battery. The battery is located under the meter panel
of the instrument. Carefully remove the panel by unscrewing the four screws on
the front of the unit and lift the unit out. Make sure battery terminal contacts
are aligned with the correct terminals. Replace meter panel to instrument
housing.

INSTRUMENT GUARANTEE

This instrument and probe, except for the battery, are guaranteed to be free
from defects in material and workmanship for six months from original
purchase date. If within that time the instrument is found to be defective, it
will be repaired without charge (except for transportation expense to LaMotte
Company, PO Box 329, Chestertown, Maryland 21620).

This guarantee is void under the following circumstances: operator’s negligence,
improper application, and unauthorized servicing.

GENERAL PRECAUTIONS

Read the instruction manual before attempting to set up or operate this
instrument. Failure to do so could result in personal injury or damage to the
instrument.

LIMITS OF LIABILITY

Under no circumstances shall LaMotte Company be liable for loss of life,
property, profits or other damages incurred through the use or misuse of their
products.

PACKAGING AND DELIVERY

Experienced packaging personnel at LaMotte Company assure the adequate
protection against normal hazards encountered in transportation of shipment.
After the product leaves the manufacturer, all responsiblity for safe delivery is
assured by the transportation company. Damage claims must be filed
immediately with the transportation company to receive compensation for
damaged goods.

TABLE OF CONTENTS

SPECIFICATIONS

Conductivity Meter ....................................................................................... 3

Conductivity Probe........................................................................................ 4

General Operating Procedure .................................................................. 5 - 6

SPECIAL PROCEDURES

Boiler Water................................................................................................... 6

Total Dissolved Salts - Soil ...................................................................... 6 - 7

Soluble Salts - Greenhouse Soil.................................................................... 7

Salinity........................................................................................................... 8

Calibration Procedure.................................................................................... 9

Battery Replacement.................................................................................... 10

Instrument Guarantee.................................................................................. 10

Limits of Liability......................................................................................... 10

Packaging and Delivery ............................................................................... 10

SPECIFICATIONS FOR CONDUCTIVITY METER

METER IN FOR MA TION

Range: Multi-Range

Low: 0-10 in 0.2 micromhos/cm increments
Medium: 0-100 in 2 micromhos/cm increments
Standard: 0-1,000 in 20 micromhos/cm increments
High: 0-10,000 in 200 micromhos/cm increments

Accuracy:
Precision:

± 1% full scale reading (all ranges)
± 0.5% full scale reading (all ranges)

FUNC TION CON TROLS

Operation Switch:

BAT.CK.- To check battery reserve
OFF - Cuts off energy supply
CAL (Calibration) - To calibrate instrument
ON - Turns instrument on for reading

Calibration: Calibrates instrument by regulating voltage potential
Temperature Compensator:

0° to 100°C in 5°C increments - adjusts instrument to
temperature of sample being tested

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Range Selector:

X.1 - conductivity reading multiplied by 0.1
X1 - conductivity reading multiplied by 1
X10 - conductivity reading multiplied by 10
X100 - conductivity reading multiplied by 100

Other Specifications

Connector: Standard BNC for conductivity probe
Power: Battery - single 9 volt transistor

(Replacement types - Eveready 216, Burgess 2U6, RCA
V5323, RAY-O-VAC 1604).

Dimensions: 3 n” width x 2 r” depth x 6 c” height
Weight: 1.7 lbs.

CARRYING CASE

Dimensions: 10” width x 6” depth x 6 c” height
Weight: With meter, 3.5 lbs.

SPECIFICATIONS FOR CONDUCTIVITY PROBE

Range: 0-10,000 micromhos/cm
Size: 3” x t”
Weight: 2 oz.
Cable Length: 3 ft.
Probe Constant: 2.0/cm
Elements: Carbon

NOTES ON THE USE OF CON DUC TIV ITY PROBE

The sensing elements of the conductivity probe consists of two carbon elements
rigidly supported in a rugged plastic material. These elements have a very
precise parallel spacing which determines the probe cell constant. To keep this
spacing and to assure accurate results, it is essential that the probe is properly
maintained and kept clean.

1. When conductivity measurements are made, the probe must be immersed in
sufficient solution to cover the bottom groove. The probe may be
completely immersed within the sample without adversely affecting the
results.

2. The conductivity probe must be kept from contacting the bottom or sides of
the container which holds the sample. Contact with surfaces other than the
solution might result in inaccurate readings since the current flow may be
altered between the probe elements.

3. After the completion of the conductivity measurement, rinse inside and
outside of probe thoroughly with water, preferably deionized water. Allow
probe to air dry completely before storing. The probe may be stored dry
indefinitely without any damage.

CALIBRATION PROCEDURE

Although each conductivity meter is precalibrated before it leaves the
manufacturer, it may become necessary to check the calibration, especially if
the conductivity probe is different from the one originally supplied with the
unit. This procedure should only be attempted by qualified personnel. Please
read the instructions thoroughly before starting.

Two accurately-prepared standard conductivity solutions are required for the
calibration procedure*. These solutions may be prepared with reagent grade
potassium chloride (KCl) in the following manner:

Solution #1: 0.005M KCl: In a 1.0 liter volumetric flask, dissolve 0.3725g
anhydrous KCl in deionized or distilled water and dilute to 1.0 liter mark.
At 25°C this solution has a conductivity of 718 micromhos/cm.

Solution #2: 0.05 M KCl: In a 1.0 liter volumetric flask dissolve 3.725g
anhydrous KCl in deionized or distilled water and dilute to 1.0 liter mark.
At 25°C this solution has a conductivity of 6,668 micromhos/cm.

*Prepared standard conductivity solutions may be ordered from LaMotte Company (see page 10).

PRO CE DURE

1. Follow steps 1-3 in General Operating Procedure, page 4.

2. Set the range selector at “X10” and switch the control knob to the “ON”

position. Measure the temperature of the 718 micromhos/cm solution
(Solution #1) and set the “TEMP” knob accordingly. Sufficiently immerse
the probe in the solution to at least cover the end slots. Adjust the “STD”
knob until the meter reading corresponds to the solution value.

3. Remove the 4 screws from the meter panel and lift unit from the base
thereby exposing the internal circuitry.

4. Switch the control knob to the “CAL.” position and adjust to a full scale
reading of 100 micromhos/cm by using the internal trim pot labeled “full
scale” located on the PC board where the switches are mounted.

5. Switch the control knob to the “ON” position and the range selector to
“X100". The ”TEMP", “STD”, and internal calibration pot should not be
changed for the X100 range. Sufficiently immerse the probe in the 6,668
micromhos/cm solution (Solution #2) to cover the end slots. Adjust the
trim pot labeled “X100" located on the meter PC board until the meter
reading corresponds to the solution value.

6. The instrument is now calibrated for all ranges.

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FOR CHANGING CONDUCTIVITY* INTO SALINITY

CONVERSION TABLE

CONDUCTIVITY SALINITY

0°C 5°C 10°C 15°C 20°C 25°C 30°C

1,200 1,400 1,500 1,700 2,000 2,200 2,400 1
2,220 2,500 2,900 3,300 3,700 4,100 4,500 2
3,200 3,700 4,200 4,700 5,300 5,900 6,500 3
4,100 4,700 5,400 6,100 6,900 7,600 8,400 4
5,000 5,800 6,600 7,500 8,400 9,300 10,300 5
5,900 6,800 7,900 8,800 9,900 11,000 12,100 6
6,700 7,800 8,900 10,100 11,300 12,600 13,900 7
7,600 8,800 10,100 11,400 12,800 14,200 15,700 8
8,500 9,800 11,200 12,700 14,200 15,800 17,400 9

9,300 10,800 12,300 13,900 15,600 17,300 19,100 10
10,200 11,800 13,400 15,200 17,000 18,900 20,800 11
11,000 12,800 14,500 16,400 18,900 20,400 22,500 12
11,900 13,700 15,600 17,600 19,700 21,900 24,100 13
12,600 14,600 16,700 18,900 21,100 23,400 25,800 14
13,400 15,600 17,800 20,100 22,400 24,900 27,400 15
14,200 16,400 18,800 21,200 23,800 26,400 29,100 16
15,000 17,400 19,800 22,400 25,100 27,800 30,700 17
15,800 18,300 20,900 23,600 26,400 29,300 32,300 18
16,600 19,200 21,900 24,800 27,700 30,700 33,900 19
17,400 20,100 23,000 25,900 29,000 32,200 35,500 20
18,200 21,100 24,000 27,100 30,300 33,600 37,000 21
19,000 22,000 25,100 28,300 31,600 35,000 38,600 22
19,800 22,900 26,100 29,400 32,900 36,500 40,100 23
20,600 23,800 27,100 30,600 34,200 37,900 41,700 24
21,400 24,700 28,100 31,700 35,400 39,300 43,200 25
22,100 25,500 29,100 32,800 36,700 40,700 44,800 26
22,800 26,400 30,100 33,900 37,900 42,100 46,300 27
23,600 27,300 31,100 35,100 39,200 43,500 47,800 28
24,400 28,100 32,100 36,200 40,400 44,800 49,400 29
25,200 29,000 33,100 37,300 41,700 46,200 50,900 30
26,000 30,000 34,100 38,500 43,000 47,600 52,400 31
26,800 30,900 35,100 39,600 44,200 49,000 53,900 32
27,500 31,700 36,100 40,700 45,400 50,300 55,400 33
28,300 32,600 37,100 41,800 46,700 51,700 56,800 34
29,100 33,500 38,100 42,900 47,900 53,000 58,300 35
29,700 34,200 39,000 44,000 49,100 54,400 59,800 36
30,500 35,100 40,000 45,100 50,300 55,700 61,300 37
31,200 36,000 41,000 46,200 51,500 57,100 62,800 38
32,000 36,800 41,900 47,200 52,700 58,400 64,200 39
32,700 37,700 42,900 48,300 53,900 59,700 65,700 40

*Conductivity values are given in micromhos/cm.
Data derived from the equation of P.K. Weyl, Limnology and Oceanography; 9,75 (1964).

GENERAL OPERATING PROCEDURE

1. Plug the probe into the BNC receptacle (top right corner of panel).

2. With the control knob in the “OFF” position, the meter pointer must

balance at zero. The mirror-faced scale insures accurate readings by

0/

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eliminating errors due to parallax problems which would otherwise occur
when the indicating needle and the scale are not properly aligned by the
reader’s eye.

3. Switch the control knob to the “BAT. CK.” position. The meter should
indicate greater than 80 micromhos/cm. If not, replace the battery (see
instructions for battery replacement, page 8).

4. Set the “TEMP” knob at 25°C, the Range Selector at “X10”, and switch
the control knob to the “CAL” position. The meter should indicate exactly
100 micromhos/cm. If not, carefully adjust by using the “STD” knob.

SAM PLE MEA SURE MENT - METHOD A
NOR MAL AC CU RACY WITH TEM PER A TURE COM PEN SA TION

5. Use the thermometer (1066) to measure the sample water temperature in
degrees centigrade. Set the “TEMP” knob at this figure.

6. Immerse the probe in at least a” of solution. Make sure all bubbles are
removed from the probe.

7. Switch the control knob to the “ON” position and the range selector to
either “X1”, “X10”, “X100”, or “X1000”. Read the conductivity directly
from the meter face. For the best accuracy, select the range which gives
readings as close to mid-range of the scale as possible. Multiply the reading
from the meter face by the appropriate factor. The probe should not be in
contact with any surface other than the solution under test.

8. After completing the conductivity measurement, switch the control knob to
the “OFF” position. Rinse the probe thoroughly with water, preferably
deionized water, and air dry.

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SAM PLE MEA SURE MENT - METHOD B
MAX I MUM AC CU RACY WITH TEM PER A TURE COR REC TION

5. Use the thermometer (1066) to measure the sample water temperature.
Record this temperature. The “TEMP” knob should be still set at 25°C.

6. Immerse the probe into sufficient solution to at least cover the end slots of
the probe. Make sure all bubbles are removed from the probe.

7. Switch the control knob to the “ON” position and the range selector to
either “X.1", ”X1", “X10", or ”X100". Select the range which gives readings
as close to the middle of the scale as possible. Record the reading. During
this test the probe should not touch any surface of the sample container.

8. Calculate result:

Conductivity, micromhos/cm at 25°C =

Meter Reading x Range Factor x [1.0 + 0.02 (T-25)]

T = Temperature of Sample in °C

9. After the measurement, switch the meter to “OFF”. Rinse probe thoroughly
with water, preferably deionized water, and air dry.

NOTE: Reference solutions which have known conductivities may be
prepared by consulting the latest edition of Standard Methods for the
Examination of Water and Wastewater, American Public Health Association,
1015 East Eighteenth Street, NW, Washington, DC 20036. A series of
accurately prepared reference solutions in both the high range and low
range allow the operator to check on the manipulative procedure as well as
the verification of results.

DETERMINATION OF
CONDUCTIVITY & TDS IN BOILER WATER

In boiler water where high concentrations of hydroxides may be evident, it is
necessary to neutralize the sample solution with gallic acid or lactic acid.
Otherwise false high conductivity readings will be noted. For a 100 mL sample
add 0.4 grams of gallic acid or lactic acid. This will neutralize approximately
1300 ppm hydroxide alkalinity. If a small amount of gallic acid or lactic acid
does not dissolve within the sample solution, the conductivity reading will not
be affected. On some highly alkaline waters higher concentrations of gallic acid
or lactic acid may be required.

The determination of conductivity for boiler water is made by following the
General Operating Procedure given on Page 4. To convert the conductivity
reading to Parts Per Million Total Dissolved Solids (ppm TDS), multiply the
reading by 0.7.

EXAMPLE: Conductivity reading is 3500 micromhos/cm.

3500 x 0.7 = 2450 ppm TDS

DETERMINATION OF SOIL
CONDUCTIVITY & TOTAL DISSOLVED SALTS

An approximation of the Total Dissolved Salts in soil is obtained by making a
soil extraction with distilled water and measuring the conductivity of the soil
extract. For purposes of comparison, all conductivity values are recorded at
25°C.

NOTE: For determination of Soluble Salts in greenhouse soils, see below.

PRO CE DURE

1. Fill a 50 mL beaker full with the soil to be tested. Tap it lightly to eliminate
any air trapped. Strike the excess soil off the surface.

2. Empty the contents of the beaker into a 250 mL widemouth flask and add
100 mL of distilled water.

3. Stopper and shake vigorously. Allow to stand for thirty minutes. During the
thirty minutes waiting period the sample should be shaken vigorously three
or four times.

4. Filter the contents of the flask and collect filtrate in suitable conductivity
chamber.

5. Take conductivity reading according to method given for General
Operating Procedure on page 4.

6. To convert to Total Dissolved Salts use the following formula:

micromhos/cm @ 25°C x 0.7 = ppm Total Dissolved Salts

If the Soluble Salts as determined above are greater than 1000 ppm, the
chlorides and sulfates should be determined in order to learn whether the
Soluble Salts are chlorides or sulfates.

Usually in calcareous soils, the sulfates represent gypsum and cause little injury
to plants, while high concentrations of chlorides might result in damage to the
plants. Greenhouse and sensitive plants may be damaged if the Souble Salts are
over 500 ppm of chlorides.

DETERMINATION OF SOLUBLE SALTS FOR GREENHOUSE SOILS

The LaMotte Multi-Range Conductivity Meter may be used to read
conductivity in the limited volume of soil extract obtained through the soil
extraction procedure employed in the LaMotte Model GS-01 Greenhouse
Outfit. Follow the extraction procedure in the GS-01 manual. Take
conductivity reading according to method given for General Operating
Procedure on Page 5. Use the following formula to convert the conductivity
reading to parts per million Soluble Salts:

Conductivity Reading (micromhos/cm) x 0.7 = ppm Soluble Salts

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