Grundfos CRE Serie Instrucciones De Instalación Y Funcionamiento página 24

12. External forced-control signals
The pump has inputs for external signals for these forced-control
functions:
• Start/stop of pump
• Digital function.
12.1 Start/stop input
Functional diagram: Start/stop input:
Start/stop (terminals 2 and 3)
H
H
12.2 Digital input
By means of the R100, one of the following functions can be
selected for the digital input:
• Normal duty
• Min. curve
• Max. curve
• External fault
• Flow switch
• Dry running.
Functional diagram: Input for digital function
Digital function
(terminals 1 and 9)
H
H
H
H
5 s
H
5 s
H
24
Normal duty
Q
Stop
Q
Normal duty
Q
Min. curve
Q
Max. curve
Q
External fault
Q
Flow switch
Q
Dry running
Q
13. External setpoint signal
The setpoint can be remote-set by connecting an analogue signal
transmitter to the input for the setpoint signal (terminal 4).
Setpoint
External setpoint
Fig. 29 Actual setpoint as a product (multiplied value) of
setpoint and external setpoint
Select the actual external signal, 0-10 V, 0-20 mA, 4-20 mA, via
the R100. See section 9.3.3 External
If control mode uncontrolled is selected by means of the R100,
the pump can be controlled by any controller.
In control mode controlled, the setpoint can be set externally
within the range from the lower value of the sensor measuring
range to the setpoint set on the pump or by means of the R100.
Actual setpoint
Sensor
Setpoint set by means of
control panel, R100 or PC Tool
E-products
Actual
setpoint
Sensor
0 10 V
0 20 mA
4 20 mA
Fig. 30 Relation between the actual setpoint and the external
setpoint signal in control mode controlled
Example: At a sensor value of 0 bar, a setpoint set of 3 bar
min
and an external setpoint of 80 %, the actual setpoint will be as
follows:
Actual setpoint = (setpoint - sensor
sensor
min
= (3 - 0) x 80 % + 0
= 2.4 bar
In control mode uncontrolled, the setpoint can be set externally
within the range from the min. curve to the setpoint set on the
pump or by means of the R100.
Actual setpoint
Max
Setpoint set by means of
control panel, R100 or PC Tool
E-products
Actual
setpoint
Min
0 10 V
0 20 mA
4 20 mA
Fig. 31 Relation between the actual setpoint and the external
setpoint signal in control mode uncontrolled
Actual setpoint
setpoint.
max
min
External setpoint signal
) x % +
min external setpoint
curve
curve
External setpoint signal