In control modules with an internal state, the output signal might be limited, for example,
when a succeeding control module is in Backtracking mode or has reached a maximum or minimum value.
Information on this situation is passed backwards in the control loop chain in the ControlConnection data structure.
The preceding control module with an internal state then stops further increase or decrease of the signal value.
Invensys Foxboro: I/A Series system, FBM (field input/output module) sequence control, trapezoidal logic control, accident recall processing, DAC, input/output signal processing, data communication and processing. Invensys Triconex: Redundant fault-tolerant control system, the most modern fault-tolerant controller based on triple modular redundancy (TMR) structure. Westinghouse (Westinghouse): OVATION system, WDPF system, MAX1000 system spare parts. Rockwell Allen-Bradley: Reliance Ryan, SLC 500/1747/1746, MicroLogix/1761/1763/1762/1766/1764, CompactLogix/1769/1768, Logix 5000/1756/1789/1794/1760/1788, PLC-5/1771/1785, etc.
