Grundfos Control MPC Montage- Und Betriebsanleitung Seite 69

8.6.65 Pumps outside duty range (4.4.7)
Pumps outside duty range
Description
The function gives a warning if the duty point of the pumps
moves outside the defined range. For instance, if the inlet pressure
becomes lower than a minimum permissible value, thus causing a
risk of cavitation for some pump types.
The warning is given with a set time delay. You can set whether
the warning is to be reset automatically or manually when the duty
point comes within the defined duty range. You can also set a
relay output to be activated when the warning is given, and to be
deactivated when the warning is reset.
This function requires that the outlet pressure and the inlet pressure
(either measured or configured) or the differential pressure of the
pumps is monitored, and that CU 352 contains valid pump data
from either a GSC file or from manual input. See section Pump
curve data (4.3.19).
Setting range
• Setting of manual or automatic resetting.
• Setting of warning delay.
Setting via the operating panel
• Settings > Monitoring functions > Pumps outside duty
range > Manual / Auto > Set warning delay.
Factory settings
The function is disabled.
Related information
8.6.43 Pump curve data (4.3.19)
8.6.66 Pressure relief (4.4.8)
Pressure relief
Description
The purpose of the function is to reduce the pressure in the pipes
by opening a solenoid valve if it exceeds a set limit. If the pressure
is not reduced within a given time, the solenoid valve will be closed,
and a warning can be given.
Y
1 2
A
B
Pressure relief
Pos. Description
A Valve opening pressure
B Valve opening pressure minus band
C Warning delay
D Band
X Time [sec]
Y P [bar]
1 Solenoid valve opens.
2 Solenoid valve closes.
3 Solenoid valve opens.
4 Warning is activated.
5 Solenoid valve closes, and warning is reset.
Setting range
• Setting of digital output.
• Setting of pressure to be monitored.
• Setting of valve opening pressure.
• Setting of band for valve opening pressure.
• Setting of warning or alarm.
4 5
3
D
X
C
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