LaMotte P-54 User Manual

MODEL DA-1

CODE 1929

MULTI-RANGE
CONDUCTIVITY METER

OPERATOR’S MANUAL

LaMOTTE COM PANY

Helping People Solve Analytical 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

61918 · 9/03

INTRODUCTION

The DA-1 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 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 3½" 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 0-100,000 micromhos/cm. A single conductivity probe
on a three foot cable is used to measure all four ranges.

REPLACING THE BATTERY

When 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, Chestertown, Maryland 21620).

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

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 of our products against normal hazards encountered during
shipment. After the product leaves the manufacturer, all responsiblity for
its safe delivery is assured by the transportation company. Damage claims
must be filed immediately with the transportation company to receive
compensation for damaged goods.

Should it be necessary to return the instrument for repair or servicing, pack
instrument carefully in suitable container with adequate packing material.
Contact the Technical Services Department for a Return Authorization
Number Attach a letter to the shipping carton describing the kind of
trouble experienced. This valuable information will enable the service
department to make the required repairs more efficiently.

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PRO CE DURE

1. Follow steps 1-3 in General Operating Procedure.

2. Set the range selector at “X100" and switch the control knob to the

”ON" position. Measure the temperature of the 6,668 micromhos/cm
solution (Solution #1) and set the “TEMP” knob accordingly.
Sufficiently immerse the probe in the solution to at least cover the
vent holes. 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 “X1000.” The “TEMP,” “STD,” and internal calibration pot should
not be changed for the X1000 range. Sufficiently immerse the probe
in the 58,640 micromhos/cm solution (Solution #2) to cover the vent
holes. Adjust the trim pot labeled “X1000" located on the meter PC
board until the meter reading corresponds to the solution value.

6. The instrument is now calibrated for all ranges.

The following prepared conductivity solutions are available from LaMotte
Company. Use the specified code number to order.

STAN DARD CON DUC TIV ITY SO LU TIONS

DESCRIPTION SIZE CODE

0.0005M KCl, 74 micromhos/cm 500 mL 6416-L

0.005M KCl, 718 micromhos/cm 500 mL 6417-L

0.01M KCl, 1413 micromhos/cm 500 mL 6354-L

0.05M KCl, 6668 micromhos 500 mL 6418-L

0.5M KCl, 58640 micromhos 500 mL 6419-L

SPECIFICATIONS FOR CONDUCTIVITY METER

METER

Range: Multi-Range

Ac cu racy:
Pre ci sion:
Power:
Di men sions:
Weight:

FUNC TION CON TROLS

Op er a tion Switch:

Stan dard ize:
Tem per a ture Com pen sa tor:

Range Se lec tor:

CON DUC TIV ITY PROBE

Range:
Size:
Weight:
Ca ble Length:
Probe Con stant:
El e ments:

CARRYING CASE

Di men sions:
Weight:

Low: 0-100 in 2 micromhos/cm in cre ments
Me dium: 0-1000 in 20 micromhos/cm in cre ments
Stan dard: 0-10,000 in 200 micromhos/cm in cre ments
High: 0-100,000 in 2000 micromhos/cm in cre ments
± 2% full scale read ing (all ranges)
± 0.5% full scale read ing (all ranges)
Bat tery - sin gle 9 volt tran sis tor
3 ¾”W x 2 5/8”D x 6 ¼”H

1.7 lbs.

ON - Turns in stru ment on for read ing
OFF - Cuts off en ergy sup ply
BAT. CK. - To check bat tery re serve
CAL. (Cal i bra tion) - To cal i brate in stru ment
Cal i brates in stru ment by reg u lat ing volt age po ten tial
0° to 100°C in 5°C in cre ments - ad justs in stru ment

to tem per a ture of sam ple be ing tested
X1 - con duc tiv ity read ing times 1
X10 - con duc tiv ity read ing times 10
X100 - con duc tiv ity read ing times 100
X1000 - con duc tiv ity read ing times 1000

0-100,000 micromhos/cm
6" x ½"
2 oz.
3 ft.

5.0/cm
Car bon

10”W x 6”D x 6 ¼”H
With me ter, 3.5 lbs.

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NOTES ON THE USE OF THE
CONDUCTIVITY PROBE

The sensing elements of the conductivity probe consist 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 at least ½" of solution. The probe may be completely
immersed within the sample without adversely affecting the results.

2. There is a tendency for the conductivity probe to entrap air bubbles
which may result in erroneous readings. After the probe is immersed
in the test solution, tap or “jiggle” the probe until air bubbles are
removed.

3. 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.

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

GENERAL OPERATING PROCEDURE

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

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

balance at zero. To adjust the zero position, use meter-zero adjusting
screw (“X” slot screw on front of meter face). The mirror-faced scale
insures accurate readings by 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. Meter should
indicate greater than 80 micromhos/cm. If not, replace battery.
(See instructions for battery replacement, page 8.)

4. Set the “TEMP” knob at 25°C, the Range Selector at “X100,” 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.

Con duc tiv ity Sa lin ity

0°C 5°C 10°C 15°C 20°C 25°C 30°C

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

Data derived from the equation of P.K. Weyl, Limnology and Oceanography; 9,75 (1964).

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CALIBRATION

Although each conductivity meter is precalibrated before it leaves the
manufacturer, it may become necessary to check the calibration to
determine if the instrument is responding to the specifications, especially if
the conductivity probe is different from the original one 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: 0.05M KCl: In a 1.0 liter volumetric flask, dissolve 3.725g
anhydrous KCl in deionized/distilled water and dilute to 1.0 liter mark. At
25°C this solution has a conductivity of 6,668 micromhos/cm.

Solution #2: 0.5M KCl: In a 1.0 liter volumetric flask dissolve 37.25g
anhydrous KCl in deionized-distilled water and dilute to 1.0 liter mark. At
25°C this solution has a conductivity of 58,640 micromhos/cm.

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CONVERSION TABLE FOR
CHANGING CONDUCTIVITY* INTO SALINITY

If the temperature compensation knob was set to the sample temperature
when the conductivity reading was recorded, use the 25°C column to
receive the results as ppt salinity.

If temperature compensation was not used when you recorded the
conductivity reading (the temperature knob was set to 25°C), use the
column that reflects the actual sample temperature to receive results as ppt
salinity.

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 14,200 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

*Conductivity values are given in micromhos/cm.

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5. Measure the temperature of the sample solution, set the “TEMP”
knob at the mark indicating the temperature. (Note the markings are
in centigrade.) Temperature has a pronounced effect upon
conductivity, and must be monitored accurately.

6. Immerse the probe into at least ½" 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 being tested.

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

9. 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 high conductivities 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.

EX AM PLE:

Conductivity reading is 3500 micromhos/cm

3500 x 0.7 = 2450 ppm TDS

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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 page 7.

PRO CE DURE

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

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. Most other plants will grow
well in soils containing less than 1000 ppm chlorides.

DETERMINATION OF SOLUBLE SALTS
FOR GREENHOUSE SOILS

The meter is specially designed 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. 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

PRO CE DURE

1. With control knob in the “OFF” position, meter pointer must
balance at zero. To adjust the zero position, use meter-zero adjusting
screw (“X” slot screw on front of meter face). The mirror-faced scale
insures accurate readings by 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.

2. Switch the control knob to the “BAT CK” position. Meter should
indicate greater than 80 micromhos/cm, if not then replace the
battery. (See instructions for battery replacement.)

3. Set the “TEMP” knob at 25°C, the Range Selector at “X100,” and
switch the control knob to the “CAL” position. The meter should
indicate exactly 100 micromhos/cm, if not then carefully adjust by
using the “STD” knob.

4. Measure the temperature of the sample solution, then set the
“TEMP” knob at the mark indicating the temperature. (Note the
markings are in centigrade.) Temperature has a pronounced effect
upon conductivity, and must be monitored accurately.

5. Immerse the probe into soil extract (in special reading chamber) to at
least cover the slots at bottom of the probe. Make sure all bubbles are
removed from the probe.

6. 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.

7. After completing the conductivity measurement, switch control knob
to the “OFF” position. Rinse probe thoroughly with water, preferably
distilled water, and drain.

8. Do not discard soil extract if it is to be used for other chemical tests.

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