11
The TDS value in aqueous solutions is directly proportional to the con-
ductivity. The ratio between the two parameters depends on the solution.
HI9811-5
model has a fixed conversion factor set to 0.5. This means
that 1
µ
S/cm is equal to 0.5 mg/L of TDS.
Accessories needed:
• Use
HI70031
(1413
µ
S/cm) EC calibration solution or
HI70032
(1382 ppm, or mg/L) TDS calibration solution.
Note:
The conversion between EC and TDS is made by a built-in circuit,
hence it is requested to calibrate the meter only in EC or TDS
range. The other range is thus automatically calibrated.
PROCEDURE
• Pour approximately 4 cm (1½”) of a conductivity calibration solution
(e.g.
HI70031
) into a beaker. If possible, use plastic beaker to
minimize any EMC interference.
• Immerse the probe in the solution.
• Wait for a couple of minutes for thermal equilibrium to be reached.
• Tap the probe on the bottom, then shake it lightly while rotating
to make sure no air bubbles remain trapped inside the probe.
• Press the
µ
S/cm
(or
mg/L
) key.
• Turn the EC/TDS calibration knob until the display shows the EC or
TDS reading at 25 °C.
EC/TDS CALIBRATION
EC/TDS CONVERSION FACTOR
