Rievtech PR-6DC-DA-R - Page 172

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 If the updated value PV > SP, then the special function reduces the value of AQ.
 If the updated value PV < SP, then the special function increases the value of
AQ.
Dir = downwards/- (timing diagram number 2)
 If the updated value PV > SP, then the special function increases the value of
AQ.
 If the updated value PV < SP, then the special function reduces the value of AQ.
With a disturbance, AQ continues to increase / decrease until the updated value PV
again corresponds to SP. The speed with which AQ changes depends on the
parameters KC and TI. If the input PV exceeds the parameter Max., then the updated
value PV is set to the value of Max.. If the PV falls short of the parameter Min., then
the updated value PV is set to the value of Min.
If the input R is set to 1, then the AQ output is reset. As long as R is set, the input A/M
is disabled.
Sampling Time
The sampling time is fixed at 500 ms.
Parameter sets
In order to simplify the use of the PI controller, the parameters for KC, TI and Dir are
already given as sets for the following applications:
Parameter set
Application example
Parameter KC
Parameter TI
(s)
Parameter
Dir
Temperature fast
Temperature, cooling control of
small spaces; small volumes
0,5
30
+
Temperature slow
Heating, ventilation, temperature,
cooling control of large spaces;
large volumes
1,0
120
+
Pressure 1
Quick pressure change,
compressor control
3,0
5
+
Pressure 2
Slow pressure change, differential
pressure control (flow controller)
1,2
12
+
Full level 1
Vat and/or reservoir filling without
drain
1,0
1
+
Full level 2
Vat and/or reservoir filling with
drain
0,7
20
+