‘4 - 20 mA’
At 4 mA the pump is stationary –
At 20 mA the pump works at maximum stroke rate.
With current signals of less than 3.8 mA, an error message appears and
the pump stops (e.g. if a cable has broken).
‘Linear curve’
The symbol "Linear curve" appears on the LCD screen. You can enter any
pump stroke rate behaviour proportional to the current signal. For this pur‐
pose, enter any two points P1 (I1, F1) and P2 (I2, F2) (F1 is the stroke rate
at which the pump is to operate at current I1, F2 is the stroke rate at which
the pump is to operate at current I2...); this defines a straight line and thus
the behaviour is specified:
I [mA]
I 1
I 2
F1
F2
F
max
0
20
P1
P2
B0088
Fig. 31: Frequency-current diagram for "Linear curve"
Plot a diagram similar to the one above – with values for (I1,
F1) and (I2, F2) – so that you can set the pump as desired!
The smallest processable difference between I1 and I2 is 4
mA (ll I1-I2 ll ≥4 mA).
In the
‘Error message’
menu item, you can activate an error process for
these types of processing.
‘Lower side band’
Using this type of processing, you can control a metering pump using the
current signal as shown in the diagram below.
However, you can also control two metering pumps for different feed
chemicals via a current signal (e.g. one acid pump and one alkali pump
using the signal of a pH sensor). To do this, connect the pumps electrically
in series.
In the
‘Error message’
menu item, you can activate an error process for
these types of processing.
Error processing
Error processing
Set Up /
‘Menu’
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