YSI TruLine ORP 50 - Manual (Page 7)

T 814241 04/2014 7
TruLine Commissioning, measuring, testing
 Make sure the immersion depth is correct. The junction must be complete-
ly submersed in the solution. The junction is in the area of the bottom end
of the shaft (see arrow).
The level of the reference electrolyte must be at least 2 cm above the level
of the solution.
Conversion to the
standard hydrogen
electrode potential
U
H
= U
Meas
+ U
Ref
where: U
H
= ORP voltage, relative to the
standard hydrogen electrode
U
Meas
= measured ORP voltage
U
Ref
= voltage of the reference system relative to the
standard hydrogen electrode
U
Ref
is temperature dependent and can be taken from the following table
(also refer to DIN 38404-6):
T (°C) U
Ref
[mV]
TruLine ORP 50
T (°C) U
Ref
[mV]
TruLine ORP 50
0 +224 35 +200
5 +221 40 +196
10 +217 45 +192
15 +214 50 +188
20 +211 55 +184
25 +207 60 +180
30 +203