Pi Controller; Pi Controller Settings For Pressure Boosting; Pi Controller Settings For Heating And Cooling - Grundfos Control MPC Installation And Operating Instructions Manual

8.7.2 PI controller (4.1.1)

Fig. 38 PI controller
Description
The system includes a standard PI controller which ensures that
the pressure is stable and corresponds to the setpoint.
It is possible to adjust the PI controller if a faster or slower
reaction to changes of consumption is required.
A faster reaction is obtained if K
A slower reaction is obtained if K
Setting range
• Gain Kp: -30 to 30.
Note: For inverse control, set K
• Integral time Ti: 0.1 to 3600 seconds.
Setting via control panel
• Settings
• Primary controller
• PI controller.
1. Set the gain (K ) and integral time (T
p
Note: Usually it is not necessary to adjust K
Factory setting
The setting of K and T depends on the system and application.
p i

PI controller settings for pressure boosting

If the application has been set to pressure boosting in the start-up
wizard, the following values of K
• K : 0.5
p
• T : 1 second.
i
is increased and T is reduced.
p i
is reduced and T is increased.
p i
to a negative value.
p
).
i
.
p
and T will be set automatically:
p i

PI controller settings for heating and cooling

If another application than pressure boosting has been selected
in the start-up wizard, the values of K
automatically according to the table below. As the system does
not know the pipe length, the default parameters will be set
according to the table to a pipe length (L
System/application
Heating
system
L [m]
1
Q
0.5
t
L [m]
L [m]
0.5
L [m]
t
1)
Heating systems are systems in which an increase in pump
performance will result in a temperature rise at the sensor.
2)
Cooling systems are systems in which an increase in pump
performance will result in a temperature drop at the sensor.
L : Distance [m] between pump and sensor.
1
L : Distance [m] between heat exchanger and sensor.
2
ΔP: Measurement of differential pressure.
Q: Measurement of flow rate.
t: Measurement of temperature.
Δ t:
Measurement of differential temperature.
and T will be set
p i
or L ) of 5 metres.
1 2
K
p
T
i
Cooling
[seconds]
1) 2)
system
0.5 1
L < 5 m: 1
1
0.5 L > 5 m: 3
1
L > 10 m: 5
1
0.5 1
-0.5 10 + 5L
2
0.5 10 + 5L
2
-0.5 30 + 5L
2
27