Using a safety PLC to Implement the Safety Function

Rástočný, Karol; Ždánsky, Juraj; Hrbček, Jozef

doi:10.25046/aj0601119

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…This topic is dealt with in more detail, e.g. [4], [5]. HW-SI is affected by random hardware failures, and for SF, which is implemented by electronic SRCS, the proof must be provided by the quantitative analysis.…”

Section: Introductionmentioning

confidence: 99%

The Output Circuit Solution of the Safety PLC for a Larger Number of Output Points

Zdanskv

Rástočný

Hrbček

2021

2021 International Conference on Applied Electronics (AE)

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Safety PLCs (Programmable Logic Controllers) are commonly a part of the Safety Related Control System (SRCS), especially in industrial applications. In most cases, the controlled devices cannot be connected directly to the safety PLC outputs, but they require an output circuit consisting of relays or contactors. The paper deals with the solution of the output circuit for a larger number of controlled devices and analyzes the influence of selected factors (especially the switching frequency of the used relays) on the Safety Integrity Level (SIL) of the output circuit.

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Section: Introductionmentioning

confidence: 99%

The Output Circuit Solution of the Safety PLC for a Larger Number of Output Points

Zdanskv

Rástočný

Hrbček

2021

2021 International Conference on Applied Electronics (AE)

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“…• Tolerable range (TR) of difference of values from physical sensors; • A method of selecting a signal value at the output of the virtual redundant sensor if the physical sensors provide signals of different values; in general, depending on the application, either the smallest value or the largest value can be considered safer; in the case of a logic signal, it is usually a signal with a log. level 0 [21][22][23]; in the next part of the article, we assumed that the safest value is considered to be the smallest The amount of hardware and software redundancy depends on requirements for the availability and the safety integrity of such a virtual redundant sensor. In this article, we consider the processing of values in the virtual redundant sensor from a maximum of three physical sensors.…”

mentioning

confidence: 99%

“…In case of communication with VS12 is not possible, VS11 sets p = 1 indicating that results from VS12 to be ignored (possible malfunction). Both virtual sensors can send their results together (Event 4) with R id , p in slightly different times based on network conditions (T VS11 , T VS12 ), according to Formulas (20) and (21). In the case of parameter p = 0, the application can use any of the results.…”

mentioning

confidence: 99%

Simulation of Virtual Redundant Sensor Models for Safety-Related Applications

Peniak

Rástočný

Kanalikova

et al. 2022

Sensors

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Applications of safety-related control systems demand reliable and credible inputs from physical sensors, therefore there is a need to extend their capabilities to provide a validated input with high availability. Our main idea is to insert virtual sensors between physical sensors and the control system’s logic. The created solution can validate the values of real sensors and with the use of multiple virtual sensors we can achieve high availability in addition, therefore our solution is entitled as a virtual redundant sensor. It works by the digital twin’s concept and uses fusion function to calculate validated results. The fusion function is used to transform the measured values from the physical sensors according to designed numerical models. The selection of a numerical model with assigned fusion functions can be performed via the WEB-based graphical user interface. Proposal of the numerical model is created and validated on the experimental workplace with emulation of physical sensors and MQTT integration (smart IoT sensors). The results of testing have shown that our solution can be applied to validate the values of physical sensors. Proposed fusion functions calculated results according to the selected model in all cases, while non-standard cases were handled according to our definition. In addition, the high availability concept with a group of two virtual sensors has proven fast recovery and availability of results for safety-related applications as well.

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Using a safety PLC to Implement the Safety Function

Cited by 2 publications

References 6 publications

The Output Circuit Solution of the Safety PLC for a Larger Number of Output Points

The Output Circuit Solution of the Safety PLC for a Larger Number of Output Points

Simulation of Virtual Redundant Sensor Models for Safety-Related Applications

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