14
7+Series Version 2.0
ORP
ORP measurement does not require calibration. When the user is not sure about ORP electrode quality or measuring
value, use ORP standard solution to test mV value and see whether ORP electrode or meter works properly.
Clean and activate ORP electrode
After the electrode has been used over long period of time, the platinum surface will get polluted which causes
inaccurate measurement and slow response. Please refer to the following methods to clean and activate ORP
electrode:
•
For inorganic pollutant, submerge the electrode in 0.1mol/L dilute hydrochloric acid for 30 minutes, then
wash it in pure water, then submerge it in the soaking solution for 6 hours.
•
For organic or lipid pollutant, clean the platinum surface with detergent, then wash it in pure water, then
submerge it in the soaking solution for 6 hours.
•
For heavily polluted platinum surface on which there is oxidation film, polish the platinum surface with
toothpaste, then wash it in pure water, then submerge it in the soaking solution for 6 hours.
Conductivity
Conductivity cell
Two-ring cells with built-in temperature sensor can be used on this instrument. The conductivity cell uses a BNC
connector while the temperature probe uses an RCA connector. When submerge the conductivity electrode in
solution, stir the solution briefly to eliminate the air bubbles and improve response and stability.
Conductivity cell constant
The meter matches conductivity electrodes of three constants: K=0.1, K=1.0 and K=10.0. Please refer to chart below
for measuring range. Set constant per parameter P2.1.
Range
＜
20 μS/cm
0.5 μS/cm~100 mS/cm
＞
100mS/cm
Conductivity electrode
constant
K=0.1 cm
-1
K=1.0 cm
-1
K=10 cm
-1
Standard solution
84μS/cm
84 μS/cm
1413 μS/cm
12.88 mS/cm
111.9 mS/cm
Conductivity calibration solutions
The meter uses conductivity standard solution of USA series. The meter can recognize the standard solution
automatically, can perform one-point or multi-point calibration (the maximum is four-point calibration). The calibration
guide icons at the bottom left of LCD correspond to the four standard values.
Calibration guide icons
Calibration solution series
Range
84
μS/cm
0-200
μS/cm
1413
μS/cm
200-2,000
μS/cm
12.88 mS/cm
2-20 mS/cm
111.9 mS/cm
20-200 mS/cm
