The DTIME function block can be used for example to model a process delay, which can be configured to measure flow rates or the number of revolutions of drive systems.
In the following example two products, A and B, are poured into a container one after the other and mixed. First, the container is placed under the dosing device for product A, to give the amount P1. Then it is moved on a conveyor belt to the dosing device for product B to give the amount P2. The time interval between the two dosing devices is 20 s.
Measuring flow rates
The product amount P2 is regulated, but the weight in the container is P1+P2. P1 should be removed. The amount P2 corresponds to the amount measured minus the amount P1 dosed 20 s beforehand.
Measuring the servo loop at P2 corresponds to the following illustration:
Values of the data structure elements of the SUM_PARA variables:
|
Element of SUM_PARA
|
Value
|
|
SUM_PARA.K1
|
1
|
|
SUM_PARA.K2
|
1
|
