18
7.2 Digital input
By means of the R100, one of the following functions can be
selected for the digital input:
• Min. curve.
• Max. curve.
• External fault.
• Flow switch.
Functional diagram: Input for digital function:
8. External setpoint signal
By connecting an analog signal transmitter to the input for the
setpoint signal (terminal 4), it is possible to remote-set the
setpoint.
The actual external signal (
0-5 V (t
hree-phase pumps, 11-22 kW,
only), 0-10 V, 0-20 mA, 4-20 mA)
must be selected via the R100,
see section
6.3.3 Selection of external setpoint signal.
If uncontrolled operation is selected by means of the R100, the
pump can be controlled by any controller.
In
controlled-operation mode
, 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,
fig. 29.
Fig. 29
Relation between the actual setpoint and the external
setpoint signal in controlled-operation mode
Example:
At a lower pressure-sensor value of 0 bar, a setpoint
set of 3 bar and an external setpoint of 80 %, the actual setpoint
will be as follows:
H
actual
= (H
set
- H
lower
) x %
external setpoint
+ H
lower
= (3 - 0) x 80 % + 0
= 2.4 bar
In
uncontrolled-operation mode
, 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, fig. 30.
Fig. 30
Relation between the actual setpoint and the external
setpoint signal in uncontrolled-operation mode
Digital function
(terminals 1 and 9 – single-phase pumps)
(terminals 1 and 9 – three-phase pumps, 0.75-7.5 kW)
(terminals 1 and 3 – three-phase pumps, 11-22 kW)
Normal duty
Min. curve
Max. curve
External fault
Flow switch
Q
H
Q
H
Q
H
Q
H
5 s
Q
H
5 s
TM
02
95
96
34
04
T
M
02
95
96
34
0
4
0
10 V
0
20 mA
4
20 mA
0
5 V
Actual setpoint
Upper value of
sensor measuring range
Setpoint set on pump
or with the R100
Lower value of
sensor measuring range
External setpoint signal
Actual
setpoint
0
10 V
0
20 mA
4
20 mA
0
5 V
Actual setpoint
Max. curve
Setpoint set on pump
or with the R100
Min. curve
External setpoint signal
Actual
setpoint
Grundfos.bk Page 18 Tuesday, April 17, 2007 8:54 AM
