Pressure control
15
Application examples
15.2
L
15.2-1
EDS82EV903-1.0-11/2002
15.2 Pressure control
A centrifugal pump (square load characteristic) is to hold the pressure in a pipe
system at a constant level (e.g. water supply of households or industrial
premises).
)
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) Note!
l With this example, the controller must be equipped with an
application-I/O, because it required two analog inputs.
l If the pressure setpoint is selected via PC, keypad or JOG
value instead of PLC, a standard I/O will be enough.
Conditions
l
Operation with a PLC (pressure setpoint selection, night reduction).
l Setting up operation at site possible.
l The pressure is lowered during the night. The pump works in an
uncontrolled mode at low and constant speed.
l The output frequency must never fall below 10 kHz (dry running).
l Avoid pressure peaks in the system.
l Avoid mechanical resonances at approx. 30 Hz output frequency.
l Overheat motor protection.
l Error message to PLC.
l At site display of operating status and actual pressure value.
l At site pump stop.