Commissioning, measuring, checking
4210W / 4211
6
ba76138d05
06/2018
2.3
Measuring: General rules
Make sure the refilling opening for the reference electrolyte solution is
open.
Avoid the carryover of sample solution from one measurement to the next
as follows:
– Shortly rinse the sample beakers with the solution the beakers are to
be filled with next.
– Between measurements, rinse the electrode with the solution that fol-
lows. Alternatively, you can also rinse the electrode with deionized
water and then carefully dab it dry.
Immerse the electrode in the solution in a vertical or slightly tilted position.
Make sure the immersion depth is correct. The junction must be com-
pletely submersed in the solution. The junction is in the area of the bottom
end of the shaft (see arrow).
At the same time, the level of the reference electrolyte must be at least 2
cm above the level of the solution.
Conversion to nor-
mal hydrogen elec-
trode
U
H
= U
Meas
+ U
Ref
U
Ref
is temperature dependent and can be taken from the following table (see
also DIN 38404-6):
4210W / 4211
with:
U
H
= ORP, referring to the normal hydrogen electrode
U
Meas
= Measured ORP
U
Ref
= Voltage of the reference system compared to the normal
hydrogen electrode
T (°C)
U
Ref
[mV]
T (°C)
U
Ref
[mV]
4210W / 4211
4210W / 4211
0
+224
35
+200
5
+221
40
+196
10
+217
45
+192
