External Setpoint; Genibus Signal; Other Bus Standards; Maintenance And Service - Grundfos CUE Series Installation And Operating Instructions Manual

13.2 External setpoint

Terminal Type Function
53 AI 1 • External setpoint (0-10 V)
The setpoint can be remote-set by connecting an analog signal
transmitter to the setpoint input (terminal 53).
Open loop
In control mode Open loop (constant curve), the actual setpoint
can be set externally within the range from the min. curve to the
setpoint set via the CUE menu. See fig. 44.
Setpoint
Max. curve
Setpoint, CUE menu
Actual setpoint
Min. curve
0
Ext. setpoint signal
Fig. 44 Relation between the actual setpoint and the external
setpoint signal in control mode Open loop
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. 45.
Setpoint
Sensor max.
Setpoint, CUE menu
Actual setpoint
Sensor min.
0
Fig. 45 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:
(setpoint set via the CUE menu – sensor min.)
Actual setpoint =
x % external setpoint signal + sensor min.
= (3 – 0) x 80 % + 0
= 2.4 bar
Actual
setpoint
range
10 V
Actual
setpoint
range
10 V
Ext. setpoint signal
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. 46.
Setpoint
90 % of max. head
Setpoint, CUE menu
Actual setpoint
25 % of max. head
0
Ext. setpoint signal
Fig. 46 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:
(setpoint, CUE menu – 25 % of maximum
Actual setpoint = head) x % external setpoint signal + 25 % of
maximum head
= (6 – 12 x 25 %) x 40 % + 12/4
= 4.2 m

13.3 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.
If a bus signal is used, the number of settings
Note
available via the CUE will be reduced.

13.4 Other bus standards

Grundfos offers various bus solutions with communication
according to other standards.
Contact Grundfos for further details.

14. Maintenance and service

14.1 Cleaning the CUE

Keep the cooling fins and fan blades clean to ensure sufficient
cooling of the CUE.

14.2 Service parts and service kits

For further information on service parts and service kits, visit
www.grundfos.com > International website > WebCAPS.
Actual
setpoint
range
10 V
31