Rievtech EXM-12DC-DA-R-HMI, Руководство пользователя, Страница: 314 / 443

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Dir = u (timing diagram numbers 1 and 3)

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 +