7. Adjustment of zero point and span
7. Adjustment of zero point and span
Only adjust the span-setting potentiometer if calibration equipment is avail-
able which has at least three times the accuracy of the pressure sensor.
GB
7.1
Preparation (figure A)
To gain access to the potentiometers, open the instru-
ment as follows:
■
Disconnect the electrical connection from the
instrument.
■
Remove the clamping nut .
■
Carefully pull the instrument connector from the
instrument.
■
Connect the instrument connector to the power
supply and a display unit (e.g. ammeter, voltmeter)
according to the connection diagram.
7.2
Adjustment of zero point (figure B)
■
Go to the start of the measuring range.
■
Using potentiometer "Z", adjust the minimum output
signal (e.g. 4 mA).
7.3
Setting the span (figure B)
■
Go to the end of the measuring range.
■
Using potentiometer "S", adjust the maximum output
signal (e.g. 20 mA).
■
Check the zero point and if there is any deviation,
re-adjust it.
■
Repeat the procedure until the zero point and the span
are set correctly.
7.4
Finish the adjustment (figure A)
■
Disconnect the instrument connector from the power supply and the display unit.
■
Carefully push the instrument connector onto the instrument, without damaging
the wires or the seals. The seals must be clean and undamaged in order to guarantee
the given ingress protection.
■
Tighten the clamping nut .
After the adjustment, check that the system is functioning correctly.
Recommended recalibration cycle: Half-yearly
28
A
B
Operating instructions Pressure sensor, P3298