User guide

Thank you for selecting the TechPro™ Series, Model AR1, one of the
Myron L Company’s latest in a new line of digital instruments utilizing
advanced circuitry. This circuitry makes it very accurate and easy to use
(see pages 2 & 3 for Features and Specifications on this and other
models). For your convenience, on the bottom side of your AR1 is a brief
set of instructions.
Special note ...... Conductivity/TDS require mathematical correction to
25°C values (ref. Temperature Compensation, pg. 15).
On the left side of the AR1 liquid crystal display is shown an indicator of
the salt solution characteristic used to model temperature compensation
(tempco) of conductivity or its TDS conversion. The indicator can be KCl,
NaCl or 442. Internal selection affects the temperature correction of
conductivity, and the calculation of TDS from compensated conductivity
(ref. Conductivity Conversion to TDS, pg. 17).
The selection can affect the reported conductivity of hot or cold
solutions, and will change the reported TDS of a solution. Generally,
using KCl for conductivity and 442™ (Natural Water characteristic) for TDS
will reflect present industry practice for standardization. NaCl may also be
selected for either conductivity or TDS as is needed.
Your instrument, as shipped from the factory, is set for conductivity with
the KCl tempco. However, if you are measuring natural waters and wish to
have maximum accuracy, you may want to change it to the 442 tempco
setting. To change the Tempco or to read in TDS/ppm, see Solution
Selection on pg. 8.
A. Operation
Using the instrument is simple:
Rinse the Conductivity cell with test solution 3 times and Refill.
Pressing COND/TDS key starts a 20 second timer.
Note the value displayed. It’s that simple!
B. Characteristics of the Key
Your AR1 is designed to provide quick, easy, accurate
measurements by simply pressing one key.
C. Operation of the Key (See Instrument Illustration on page 1)
1. Measurement Keys in General
The measurement key turns on the instrument in the mode selected.
The mode is shown at the bottom of the display, and the measurement
units appear at the right.
This key is used with solution in the Conductivity Cell.
While filling cell cup ensure no air bubbles cling on the cell wall.
If the proper solution is not selected (KCl, NaCl or 442) refer to
Why Solution Selection is Available, pg. 8.
Solution to be tested is introduced into the conductivity cell and a press
of displays conductivity or Total Dissolved Solids (TDS) with units
on the right. On the left is shown the solution type selected for
conductivity. An overrange condition will show only [- - - -].
Rinse out the cell cup with clean water. Do not scrub the cell. For oily
films, squirt in a foaming non-abrasive cleaner, and rinse. Even if a very
active chemical discolors the electrodes, this does not affect the
accuracy; leave it alone (ref. Cleaning Cell Cup, pg. 12).
If the proper solution is not selected (KCl, NaCl or 442), see Solution
Selection, Pg. 8.
NOTE: After sampling high concentration solutions or temperature
extremes, more rinsing may be required.
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
6 7