40
Closed loop
In all other control modes, except proportional differential
pressure, the actual setpoint can be set externally within the
range from the lower value of the sensor measuring range
(sensor min.) to the setpoint set via the CUE menu. See fig. 57.
Fig. 57
Relation between the actual setpoint and the external
setpoint signal in control mode Controlled
Example:
At a sensor min. value of 0 bar, a setpoint set via the
CUE menu of 3 bar and an external setpoint of 80 %, the actual
setpoint will be as follows:
Proportional differential pressure
In control mode
Proportional differential pressure,
the actual
setpoint can be set externally within the range from 25 % of
maximum head to the setpoint set via the CUE menu. See fig. 58.
Fig. 58
Relation between the actual setpoint and the external
setpoint signal in control mode Proportional differential
pressure
Example:
At a maximum head of 12 metres, a setpoint of
6 metres set via the CUE menu and an external setpoint of 40 %,
the actual setpoint will be as follows:
20.3 GENIbus signal
The CUE supports serial communication via an RS-485 input.
The communication is carried out according to the Grundfos
GENIbus protocol and enables connection to a building
management system or another external control system.
Operating parameters, such as setpoint and operating mode can
be remote-set via the bus signal. At the same time, the pump can
provide status information about important parameters, such as
actual value of control parameter, input power and fault
indications.
Contact Grundfos for further details.
20.4 Other bus standards
Grundfos offers various bus solutions with communication
according to other standards.
Contact Grundfos for further details.
21. Maintenance and service
21.1 Cleaning the CUE
Keep the cooling fins and fan blades clean to ensure sufficient
cooling of the CUE.
21.2 Service parts and service kits
For further information on service parts and service kits, visit
www.grundfos.com > International website > WebCAPS.
T
M
03 88
56 26
07
Actual setpoint =
(setpoint set via the CUE menu – sensor min.)
x % external setpoint sensor min.
= (3 – 0) x 80 % + 0
= 2.4 bar.
T
M
03
8856
2
60
7
Actual setpoint =
(setpoint, CUE menu – 25 % of maximum
head) x % external setpoint 25 % of
maximum head
= (6 – 12 x 25 %) x 40 % + 12/4
= 4.2 m.
Setpoint
Sensor max.
Setpoint, CUE menu
Sensor min.
Ext. setpoint signal
Actual setpoint
0
10 V
Actual
setpoint
range
Setpoint
90 % of max. head
Setpoint, CUE menu
25 % of max. head
Ext. setpoint signal
Actual setpoint
0
10 V
Actual
setpoint
range
Note
If a bus signal is used, the number of settings
available via the CUE will be reduced.
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