LaMotte Multi-Range Conductivity Meter 1704 DA-LR - Manual (Page 4)

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.
4
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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