Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manuel (Page 54)

IM 12J6C3-F-E
2-2 Annexe
A-3-6. Overall accuracy test
This test can be performed by the end-user to check
the overall accuracy of the instrument. The data
specified on the Quality Inspection Certificate are
results of the overall accuracy test performed during
production and can be reproduced by performing
similar tests with the following test equipment:
1. A variable resistor box 1 (resistor decade box)
to simulate the temperate element. All tests are
performed simulating 25ºC (77 ºF).
2. A fixed resistor of ��00 ٠to simulate the
µA-output load.
3. A current source ranging from 0 µA to 50 µA,
resolution 0.01 µA with an accuracy of 0.05%
(galvanic).
4. A current source ranging from 0 nA to 1200nA,
resolution 0.01 nA with an accuracy of 0.05%
(polarographic).
5. A stabilised voltage supply unit: nominal 24 Volt
DC
6. A current meter for DC currents up to 25 mA,
resolution 1mA, accuracy 0.1%
7. A multimeter capable of measuring megohm
ranges to check insulation impedance.
8. Screened cable to connect the input signals.
Box 1 (temperature)
Resistor decade
Electrode cable, 2 mtr.
EXA DO202
mA
meter
Load Resistor
DC Power Supply
Galv
Polar
+
-
+
+
-
-
+
-
G
11
12
16
15
13
18
14
17
Galv
Polar
Figure 1. Connection diagram for the overall accuracy test