External Setpoint Function - Grundfos CRE Series Installation And Operating Instructions Manual

2. Set the maximum speed within the range from
user-set minimum speed (4) to fixed maximum
speed (1).
The range between the user-set minimum and
maximum speed is the operating range (3).
100 %
67 %
24 %
10 %
0 %
Pos. Description
1 Fixed maximum speed
2 User-set maximum speed
3 Operating range
4 User-set minimum speed
5 Fixed minimum speed

9.18 External setpoint function

Use this function to influence the setpoint by an
external signal via one of the analog inputs.
If the FM310 or FM311 functional module is fitted, you
can also influence the setpoint via one of the
Pt100/1000 inputs.
To enable the function, set one of the
analog inputs or Pt100/1000 inputs to
Setpoint influence with Grundfos GO or
to Ext. setpoint infl. with the HMI 300 or
301 operating panel.
Example of setpoint influence in control mode
Const. pressure
Actual setpoint: actual input signal × setpoint.
At a setpoint of 2 bar and an external setpoint of 60
%, the actual setpoint is 0.60 × 2 = 1.2 bar.
[bar]
1
Y1
2
Y2
2
1.2
Y3
0
Y4
3
4
Pos. Description
X: External input signal from 0 to 100 %
Y: Setpoint influence from 0 to 100 %
5
X1: Actual input signal, 60 %
Y1: Sensor maximum
Y2: Setpoint
Y3: Actual setpoint
Y4: Sensor minimum
Example of a constant curve with linear influence
function
Actual setpoint: actual input signal × (setpoint - user-
set minimum speed) + user-set minimum speed.
At a user-set minimum speed of 25 %, a setpoint of
85 % and an external setpoint of 60 %, the actual
setpoint is 0.60 × (85 - 25) + 25 = 61 %.
Y
100
0
0 100 %
X1
0.5 3.5 V
0 5 V
0 10 V
0 20 mA
4 20 mA
-50 204 °C
X
63