Controller - Grundfos Hydro Multi-E Series Installation And Operating Instructions Manual

12.6 Controller

The pumps have a factory default setting of gain (K
time (T ).
i
However, if the factory setting is not the optimum setting, you can
change the gain and the integral time:
• Set the gain within the range of 0.1 to 20.
• Set the integral-action time within the range of 0.1 to 3600
seconds.
If you select 3600 seconds, the controller functions as a P
controller.
Furthermore, you can set the controller to inverse control.
This means that if you increase the setpoint, the speed is
reduced. In the case of inverse control, you must set the gain
within the range of - 0.1 to - 20.
Guidelines for setting of PI controller
The tables below show the recommended controller settings:
Constant differential pressure
p
p
p p
L1
L1
L1: Distance in meters between pump and sensor.
Constant
Heating
temperature
system
0.5
t
L2
L2
0.5
t
1)
In heating systems, an increase in pump performance results
in a rise in temperature at the sensor.
2)
In cooling systems, an increase in pump performance results
in a drop in temperature at the sensor.
L2: distance in meters between heat exchanger and sensor.
20
) and integral
p
K T
p i
0.5 0.5
L1 < 5 m: 0.5
0.5 L1 > 5 m: 3
L1 > 10 m: 5
K
p
T
Cooling i
1) 2)
system
-0.5 10 + 5L2
-0.5 30 + 5L2
Constant differential
temperature
t
L2
t
t
t
L2
L2: Distance [m] between heat exchanger and sensor.
Constant flow rate
Q
Constant pressure
p
p
Constant level
L
L
Note: If the controller is too slow-reacting, increase the gain.
If the controller is hunting or unstable, dampen the system by
reducing the gain or increasing the integral time.
Factory setting
See section 29. Factory settings.
K T
p i
- 0.5 10 + 5L2
K T
p i
0.5 0.5
K T
p i
0.5 0.5
0.5 0.5
K T
p i
- 20 0
20 0