Management of a PEM Electrolyzer in Hybrid Renewable Energy Systems - Fuzzy Modeling and Control: Theory and Applications - page 218

Fig. 12.8 Addressing of variables of the PLC memory in WinCC flexible runtime
The sampling time chosen for the OPC blocks is 10 s. The conditioning and
un-scaling of the value Vfuzzy is carried out by the PLC cyclic interruption block
OB35 every 10 s. This value is sent to the voltage analogue output of the module
SM334. The PLC programming software STEP7, the supervision WinCC software
and Matlab software are installed in the same computer. So, the OPC Server and the
OPC Client are both local machines.
Figure 12.9 illustrates the OPC Server, the Simulink scheme and the rule viewer
running concurrently in the PC connected to the PLC.
12.5 Experimental Results
The FLC has been tested under real conditions in the test-bed for several days. The
membership functions and rules were adjusted during trials with different climatic
conditions in order to avoid fluctuations of the output signal and deviations from the
expected behavior of the electrolyzer.