Grundfos Control MPC 2000 Series, Инструкция по установке и эксплуатации

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English (GB)
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8.5.3 Control mode (2.1.2)
Fig. 19 Control mode
Description
There are two control modes, namely closed and open loop.
Closed loop
The typical control mode is "Closed loop" where the built-in PI
controller ensures that the system reaches and maintains the
selected setpoint. The performance is based on the setpoint set
for closed loop. See figs
20 and 21 .
Fig. 20 Booster system controlled by built-in PI controller
(closed loop)
Fig. 21 Regulation curve for closed loop
Setting via the operating panel
• Operation > Further settings > Control mode > Closed loop.
Set the setpoint. See sections
8.5.4 Alternative setpoints (2.1.3)
and 8.5.1 Operation (2) .
Open loop
In open-loop control mode, the pumps run at a fixed speed. The
pump speed is calculated from the performance set by the user
(0-100 %). The pump performance in percentage is proportional
with the flow rate.
Open-loop control mode is usually used when the system is
controlled by an external controller which controls the
performance via an external signal. The external controller could
for instance be a building management system connected to the
MPC system. In such cases MPC is like an actuator. See figs
22
and 23 .
Fig. 22 Booster system with external controller (open loop)
Fig. 23 Regulation curve for open loop
Fig. 24 Regulation curve for MPC-E system in open loop
TM
03
223
1
390
5
TM
03
23
9
0
41
05
P [bar]
Time [s]
Setpoint
T
M
03
2
2
3
2
39
05
T
M
03
2
3
9
1
36
07
T
M
03
9
9
7
7
48
07
0
5
Input [%] from external
controller
Flow rate [m
3
/h]
100 50 70.7 5
25
50
75
100
86.6
Flow rate [m
3
/h]
Input [%] from
external controller
Pump 1
Pump 4
Pump 3
Flow rate
Pump 2