
Hardwired logic equipment set
Hardwired logic equipment set (HL ES) is intended for designing process instrumentation and control systems (I&C) where control function is protected from software errors and cyber-threats. Control function is implemented using non-programmable equipment – hardwired logic.
The advantages typical for programmable equipment are kept. Signal processing, including analog ones, and the decision-making process is implemented entirely on non-programmable equipment, but in digital form.
- This approach provides the same high accuracy as in programmable solutions.
- Complex operations with analog signals (linearization of signals from non-linear sensors, etc.) are performed in advance with high accuracy and stored in non-volatile memory.
- Flexibility in implementation of algorithms: Analog signal processing modules can be reconfigured at site, for example, if the sensor type changed, by overwriting the non-volatile memory.
- Simple switching of connections between modules allows to change algorithms right at site
- Algorithms are designed in graphic form using a computer-aided design (CAD) system.
- The result of design is composition of modules and connections between them (instead of a downloadable code, as in the case of programmable systems).
- A high degree of informatization is implemented due to availability of a built-in redundant information network.
- The network part is programmable, while the influence of programmable equipment on the hardwired logic is eliminated by the hardware in case of any failures of the programmable part, including its physical failure.
- Capability of designing multichannel distributed systems due to transmission of signals via fiber optic networks also implemented on hardwired logic.
- Stage-by-stage self-diagnostics (testing) system also implemented on hardwired logic is integrated into the equipment.
- Compactness of the equipment is achieved by using state-of-the-science electronic components in microminiature design.
Up-to-date I&C systems are mostly implemented using programmable equipment. Programmable (computerized) systems offer flexibility in algorithm implementation, capability of complex calculations, and dimensions of the equipment. However, disadvantages of programmable systems are significant: susceptibility to programmers’ errors and vulnerability to cyber-threats. The hardwired logic equipment set (HL ES) lacks the disadvantages of programmable equipment while maintaining its advantages. Signal processing, decision-making and generation of control commands in the HL ES are fully implemented on non-programmable means — hardwired logic.

Systems based on hardwired logic are credible: they are predictable and verifiable, are not susceptible to programmers’ error and cyber-threats, continue working when programmable systems fail completely