Dwyer EC - Manual

Before You Begin:
Remove plastic strips between batteries and contacts if
present. Soak electrodes for three (3) minutes in alcohol to
remove oily residues.
Calibration:
Even though these testers are factory calibrated, it is still
necessary to check the calibration against an appropriate
standard solution and recalibrate.
Selecting Standard Calibration Solutions:
EC Conductivity Tester
When choosing a conductivity standard calibration solution,
it is possible to use any conductivity standard calibration
solution no matter what slats are used to formulate it. This
because conductivity measurements are not dependent on
chemical formulation. Thus, a conductivity calibration in one
type of conductivity standard calibration solution is
transferrable to any type of test solution, even if they
contain very different chemicals.
When choosing a conductivity standard calibration solution,
refer to the following rule:
1. Whenever possible, calibrate the instrument with a
conductivity standard calibration solution that has a
conductivity value close to the expected values of the test
solution. This will result in the best accuracy. If this is not
possible, or the conductivity values of the test solutions vary
greatly, it is recommended that the instrument be calibrated
Series TDS and EC Conductivity Testers
Specifications - Operating Instructions
Bulletin G-21-TDS/EC
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000 www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: 219/872-9057 e-mail: [email protected]
SPECIFICATIONS
Range: TDS2: 0 to 1990 ppm; TDS3: 0 to 10.00 ppt; EC1: 0 to
1990 µS; EC2: 0 to 19.90 ms.
Accuracy: ±2% FS.
Resolution: TDS2: 10 ppm; TDS3: 0.10 ppt; EC1: 10 µS; EC2:
0.10 ms.
Calibration: 1-point push button.
Calibration Standard Range: TDS2: 300 to 1990 ppm; TDS3:
3 to 10.00 ppt; EC1: 300 to 1990 µS; EC2: 3 to 19.90 ms.
Operating Temperature: 32 to 122°F (0 to 50°C).
Temperature Compensation: 32 to 122°F (0 to 50°C).
ATC Coefficient: Beta=2% per °C, 1.11% per °F, 25°C
Reference Temperature.
Display: 3-1/2 digit LCD.
Power: Four 1.5V Alkaline batteries.
Battery Life: 140 hrs continuous use.
Wetted Materials: 316 Stainless Steel and glass reinforce
thermoplastic polyester.
Weight: 4.5 oz (125 g).
to a standard that has a conductivity value in the upper one-
third of the instruments measurement range.
TDS Total Dissolved Solids Tester
A total dissolved solids (TDS) standard calibration solution
should contain the same types of dissolved solids known to
be in the test solution. Failure to do so will result in
significant discrepancies between the ppm or ppt readings
and the actual ppm or ppt of TDS in the test solution.
The easiest way to obtain a total dissolved solids standard
calibration solution is to use a ready-made standard
solution that has the same types of dissolved solids as the
solution to be tested. These ready-made solutions offer
convenience and accuracy. They are commonly formulated
with either KCl, NaCl, CaCO
3,
or442 natural water
formulation (40% sodium bicarbonate and 20% sodium
chloride) to meet the majority of applications.
Choose a ready-made calibration solution according to the
following guidelines:
1. Choose a TDS standard calibration solution that contains
the same types of dissolved solids to be tested.
2. Choose a TDS standard calibration solution that has a
ppm or ppt value as close as possible to the value of the
solution to be tested. If this is not reasonable because of the
variations in the test solutions, it is best to calibrate the TDS
indicator with a TDS standard that has a ppm or ppt value