Menu Installation; Control Mode - Grundfos CRE Instrucciones De Instalación Y Funcionamiento

4.4 Menu INSTALLATION

4.4.1 Control mode

Without sensor
(uncontrolled)
Select one of the following
control modes (see fig. 14):
• Controlled
• Uncontrolled.
If the pump is connected to a bus, the control mode
cannot be selected via the R100. See section
4.9 Bus signal.
4.4.2 Controller
E-pumps have a factory default setting of gain (K
time (T ). However, if the factory setting is not the optimum
i
setting, the gain and the integral time can be changed in the
display below.
• The gain (K ) can be set within the range from 0.1 to 20.
p
• The integral time (Ti) can be set within the range from 0.1 to
3600 s. If 3600 s is selected, the controller will function as a P
controller.
• Furthermore, it is possible to set the controller to inverse
control, meaning that if the setpoint is increased, the speed
will be reduced. In the case of inverse control, the gain (Kp)
must be set within the range from -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.
With pressure sensor
(controlled)
Select one of the following
control modes (see fig. 14):
• Controlled
• Uncontrolled.
) 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
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.
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
General rules of thumb
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.
K
p
T
Cooling i
1) 2)
system
-0.5 10 + 5L2
-0.5 30 + 5L2
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
15