14
EXT mode
■ Analogue proportional control
ANA. P (analogue preset) programming (see page 42 & 54)
Select a proportional control pattern. 4 - 20mA, 20 - 4mA, 0 - 20mA and 20 - 0mA are available. During opera
-
tion, the display shows the current flow rate. To show the current value, push the key. To return to the flow
rate display, push the key.
The left graph shows the flow rate at each
pattern.
a. 4 - 20mA
b. 20 - 4mA
c. 0 - 20mA
d. 20 - 0mA
*
The flow rate falls to 0mL/H if the pump runs
beneath the minimum rate.
*
The pump does not run over the maximum flow
rate at any current value
.
Example of use: pH control in a water treatment system
Supply tank
pH meter
Electrode
Pump
4-20mA signal
0
4
20
a
d
c
b
Flow rate
[L/H]
4-20mA analogue signal
Max
Min
Operational functions
