Electrical Calibration; Equipment Required; Preparation - ABB 4670 Series User Manual

6.5 Electrical Calibration

Caution. The instrument is calibrated by the company prior to despatch and an electrical calibration should not be necessary. If
an electrical calibration is carried out, suitably calibrated and verifiable test equipment must be used.

6.5.1 Equipment Required

a) Millivolt source 0 to +4000 mV.
b) Digital milliammeter (current output measurement): 0 to 20 mA.

6.6 Preparation

a) Switch off the supply and disconnect the turbidity cell and current output from the electronics unit terminal block – see Fig. 3.4
or Fig. 3.5.
b) Wall Mounted Instruments
1) Connect the millivolt source '+' and '–' to terminals 4 and 7 respectively.
2) Connect the milliammeter to the retransmission output terminals.
3) Ensure the earth on the millivolt source is connected to the earth stud.
Panel Mounted Instruments
1) Connect the millivolt source '+' and '–' to terminals 9 and 6 respectively.
2) Connect the milliammeter to the retransmission output terminals.
3) Ensure the earth on the millivolt source is connected to the earth stud.
c) Switch on the supply and allow ten minutes for the circuits to stabilize.
d) Select
ELECTRICAL CAL Page
and proceed as in Section 6.7, following.
6 PROGRAMMING & ELECTRICAL CALIBRATION
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