En
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is
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G
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56
15.2.12 Continuous controller with disturbance variable feedforward
Application
•
Open-loop control of dosed chlorine proportional
to the flow and closed-loop control dependent on
the measured value.
•
Control of dosing pump or gas dosing unit via the
current input.
Description
A varying flow of water is to be chlorinated by a
uniform amount. The electromagnetic flowmeter
measures the flow quantity and passes it on to the
controller. The result (the chlorine concentration) is
also measured and the dosed quantity controlled
accordingly.
•
When the flow of water increases:
– The current signal increases.
•
When the flow of water decreases:
– The current signal decreases.
•
The closed-loop control is dependent on the
measured value:
– When the chlorine concentration decreases,
the current signal is additionally increased.
– When the chlorine concentration increases, the
current signal is additionally decreased.
Parameter settings
SP 1
Required chlorine concentration, e.g. 38 %.
Pulse frequency for SP 1
0
SP 2
-
*)
Pulse frequency for SP 2
-
X
p
e.g. 100 % (transmission ratio 1:1)
• > 100 % (transmission ratio 1: > 1)
• < 100 % (transmission ratio 1: < 1)
T
n
e.g. 300 sec
• Higher setting results in slower control.
• Lower setting results in faster control.
T
v
0
Hysteresis
-
Interpulse period
-
Actuating time
0
Minimum pulse width
1 sec - so that the relays required here do not activate
unnecessarily.
Required code functions
1, 3, 4, 10, 11, 14
Other code functions
As required
*)
"-": without function (no setting required)
