Calibration; Equipment Required; Preparation - ABB AX416 User Manual

7 CALIBRATION

Notes.
• The analyzer is calibrated by the Company prior to dispatch and the Factory Settings pages are protected by an access
code.
• Routine recalibration is not necessary – high stability components are used in the analyzer's input circuitry and, once
calibrated, the Analog-to-Digital converter chip self-compensates for zero and span drift. It is therefore unlikely that the
calibration will change over time.
• attempt recalibration without first contacting ABB.
Do Not
• attempt recalibration unless the input board has been replaced or the Factory Calibration tampered with.
Do Not
• Before attempting recalibration, test the analyzer's accuracy using suitably calibrated test equipment – see Sections 7.1
and 7.2.

7.1 Equipment Required

a) Millivolt source (pH or Redox input simulator): –1000 to 1000 mV.
b) Decade resistance box (Pt100/Pt1000 temperature input simulator): 0 to 10k (in increments of 0.01), accuracy 0.1%.
c) Digital milliammeter (current output measurement): 0 to 20mA.
Note. Resistance boxes have an inherent residual resistance that may range from a few m up to 1. This value must be
taken into account when simulating input levels, as should the overall tolerance of the resistors within the boxes.

7.2 Preparation

a) Switch off the supply and disconnect the electrode system, temperature compensator(s) and current output(s) from the analyzer's
terminal blocks.
b) Sensor A – Fig. 7.1:
1) Link terminals B9 and B10.
2) Connect the millivolt source to terminals B14 (–ve) and B16 (+ve) to simulate the pH or Redox input. Connect the millivolt
source earth to the Case Earth (Ground) Stud – see Fig. 6.8 (wall-/pipe-mount analyzer) or Fig. 6.10 (panel-mount analyzer).
3) Connect the 0 to 10k decade resistance box to terminals B9 and B11 to simulate the Pt100/Pt1000/Balco 3K.
Sensor B (dual input analyzers only) – Fig. 7.1:
1) Link terminals B1 and B2.
2) Connect the millivolt source to terminals B6 (–ve) and B8 (+ve) to simulate the pH or Redox input. Connect the millivolt source
earth to the Case Earth (Ground) Stud – see Fig. 6.8 or (wall-/pipe-mount analyzer) or Fig. 6.10 (panel-mount analyzer).
3) Connect the 0 to 10k decade resistance box to terminals B1 and B3 to simulate the Pt100/Pt1000/Balco 3K.
c) Connect the milliammeter to the analog output terminals.
d) Switch on the supply and allow ten minutes for the circuits to stabilize.
d) Select the
FACTORY SETTINGS
Sensor A Terminal Numbers
Sensor B Terminal Numbers
Temperature
Simulator
Fig. 7.1 Analyzer Terminal Links and Decade Resistance Box Connections
56
page and carry out Section 7.3.
Terminal link
B9
B10 B11
B1 B2
B3
B12 B13 B14 B15
B4 B5 B6
–ve
B16
B7 B8
+ve
pH/Redox
Input Simulator