- 15 -
7.2
Notes about ORP
ORP measurement does not require calibration. When the user is not sure about ORP electrode quality
or measuring value, use ORP 222 mV standard solution to test mV value and see whether ORP electrode
or meter works properly. Table-9 is the data of standard ORP solution for 222 mV.
Table-9
°C
10
15
20
25
30
35
38
40
mV
242
235
227
222
215
209
205
201
7.3
Clean and activate ORP electrode
After the electrode has been used over a 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:
•
In general, soaking the ORP electrode in 222 mV for 30 minutes will help activate the ORP sensor
and restore its accuracy.
•
For inorganic pollutant, submerge the electrode in 0.1mol/L dilute hydrochloric acid for 30 minutes,
then wash it in distilled 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 distilled
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 distilled water, then submerge it in the 3M soaking solution for 6
hours.
7.4
ORP Parameter Setting
mV and ORP measurement parameter setting Table (Table (5-2))
Table (5-2)
Prompt mark
Parameter Setting Items
Code
Parameters
P1
Back light display time setting
bl
0-1-3-6 min
P2
Auto power off time setting
ac
0-10-20 min
7.4.1 Backlight display time setting (P1)
Press , the meter enters P1, see details in section 6.6.5
7.4.2 Auto power off time setting (P2)
Short press in P1 mode, the meter enters P2, see details in section 6.6.6