Myron L ARH1 - Manual (Page 6)

N O T E : After sampling high concentration solutions or temperature
extremes, more rinsing may be required. When sampling low conductivity
solutions, be sure the pH cap is well seated so no solution washes into
the conductivity cell from around the pH cap.
A. Measuring Conductivity/Total Dissolved Solids (TDS)
1. Rinse cell cup 3 times with sample to be measured. (This
conditions the temperature compensation network and prepares
the cell).
2. Refill cell cup with sample.
3. Press .
4. Take reading. A display of [- - - -] indicates an overrange
condition.
B. Measuring pH
1. Remove protective cap by squeezing its sides and pulling up.
2. Rinse sensor well 3 times with sample to be measured. Shake
out each sample to remove any residual liquid.
3. Refill sensor well with sample.
4. Press .
5. Take reading.
6. IMPORTANT: After use, fill pH sensor well with Myron L
Storage Solution, a strong KCl solution or pH 4 buffer, and
replace protective cap. Do not allow pH sensor to dry out.
N O T E : If a storage solution, KCl or pH 4 solution is unavailable, use a
saturated solution of table salt and water (ref. pH, pg. 15).
V. SOLUTION SELECTION
A. Why Solution Selection is Available
Conductivity and TDS require temperature correction to 25°C values (ref.
Standardized to 25°C, pg. 1
9 ). Selection determines the temperature
correction of conductivity and calculation of TDS from compensated
conductivity (ref. Conductivity Conversion to TDS, pg. 21).
B. The 3 Solution Types
On the left side of the display is the salt solution characteristic used to
model temperature compensation of conductivity and its TDS
conversion. Generally, using KCl for conductivity and 442 (Natural Water
characteristic) for TDS will reflect present industry practice for
standardization. Your instrument as shipped from the factory is set for
conductivity with the KCl tempco. If you are measuring natural waters and
wish to have maximum accuracy, it may be better to change it to the 442
setting. However, selecting NaCl for either conductivity or TDS may best
reflect your specific specialized needs (ref. Solution Characteristics, pg.
21).
NOTE: Before opening instrument, Dry THOROUGHLY.
C. Procedure to Select a Solution
N O T E : Check display to see if solution displayed (KCl, NaCl or 442) is
already the type desired. If not:
1. Remove the 4 bottom screws and carefully open Instrument.
2. Locate dip switch labeled “TEMP COMP” on the right side of the
circuit board. Switch positions are 1-4 (left to right).
3. Set switch numbers 1 and 2 to the desired position.
Note: Factory setting is for KCl - both switches UP or ON.
4. Carefully turn instrument over and press the key. The
correct icon “KCl”, NaCl” or “442” should be shown on the left
side of the display.
5. Replace bottom, ensuring the sealing gasket is installed in the groove
of the top half of case. Tighten screws securely. (Do NOT overtighten)
6. Recalibrate as necessary. See Calibration, pg. 10.
D. Procedure to Select the Units of Measurement
i.e. µS to ppm
1. Remove the 4 bottom screws and open Instrument.
2. Locate dip switch labeled “TEMP COMP” located on the right
side of the circuit board. Switch positions are 1-4 (left to right).
3. Set switch number 3 to the desired position - COND or TDS.
Note: Factory setting is for COND - DOWN or OFF.
4. Carefully turn instrument over and press the key. The
8 9
COND
TDS
COND
TDS
pH
COND
TDS