Fig 1.
Block diagram of setting and testing parameters of Frequency Converter PI.
Fig 2.
Scheme of the reference milking equipment.
Fig 3.
System model in Matlab / Simulink 2014a.
Fig 4.
The transient characteristic of the proportional non-oscillating controlled system.
Table 1.
PID controllers Zigler-Nichols transition characteristic method.
Fig 5.
Starting of the vacuum system of the reference device with different suction.
Table 2.
Volumes of approximate functions and times constants.
Fig 6.
Dependence of time constant on volume.
Fig 7.
Work desktop of PI controller the software Starter.
Fig 8.
Comparison of simulation with real system (optimal setting).
Fig 9.
Graphical representations of vacuum stability.
Table 3.
The accuracy of the test was verified using basic descriptive statistics.
Fig 10.
Adjustment of proportional component (P) in dependence on piping volume (V) and flow rate (QV).
Table 4.
Change of the proportional component P in relation to the air flow.
Fig 11.
The values of the relative energy savings during the VFD.