Siemens SIMATIC S7-1500R/H Getting Started page 40

Flow diagram for traffic light and cabinet control FB20
FB20 calls FB21. Depending on the status of the air pollution level (FB13) in the tunnel
sections, both traffic lights are set to green, yellow or red and the barriers are opened or
closed.
Figure 3-3
S7-1500R/H redundant system
Getting Started, 10/2018, A5E44910930-AA
Flow diagram for traffic light and cabinet control FB20
Programming
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