Formalization and Verification of PLC Timers in Coq

Wan, Hai; Chen, Gang; Song, Xiaoyu; Gao, Ming

doi:10.1109/compsac.2009.49

Cited by 18 publications

(19 citation statements)

References 8 publications

(11 reference statements)

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“…Theorem TransQ2Q3 describes that the system's current state is q2, if guard timeout is true and opened is false, then the next system's state will be q3. Proving such a theorem in the framework described in [4] takes tens of lines, while in this framework it only takes one single tactic. To summer up, a component is modeled by a Record type in Coq, accompanied with a set of additional properties and a set of help proof tactics.…”

Section: ) Compound Componentsmentioning

confidence: 99%

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Parameterized Specification and Verification of PLC Systems in Coq

Wan

Song

Gao

2010

2010 4th IEEE International Symposium on Theoretical Aspects of Software Engineering

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Abstract-Programmable logic controllers (PLCs) represent a typical class of embedded software systems. They are widely used in safety-critical industrial applications, such as railways, automotive applications, etc. The paper presents a novel method to specify and verify PLC software systems with the theorem proving system Coq. Dependent inductive data types are harnessed to represent the component specifications. Modular and parameterized specification and verification are proposed. An illustrative example demonstrates the effectiveness of the method.

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Section: ) Compound Componentsmentioning

confidence: 99%

“…Hence a TON-timer is modeled by a Record type with a parameter of type nat. Three specifications are deployed to describe the behaviors of a TON-timer (for detailed description of these specifications, please refer to [4]). By applying TONTimer to 3000 we obtain a TON-timer whose PT is 2 In PLCs, P T of a TON-timer is a constant.…”

Section: ) Atomic Componentsmentioning

confidence: 99%

Parameterized Specification and Verification of PLC Systems in Coq

Wan

Song

Gao

2010

2010 4th IEEE International Symposium on Theoretical Aspects of Software Engineering

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“…Additionally, the use of timing functions play an important role in PLC for real time applications. The formalization of timers application for PLC control programs at abstract level is explained thoroughly by Hai Wan et al (5) . In this paper, they have formally proved the correctness of PLC programs by using Coq theorem prover, in which the timer control is applied.…”

Section: Related Studiesmentioning

confidence: 99%

“…( 1 ) arm moves backward to the rear-top position from the front-top (home) position ( 2 ) 4 grip u 5 to pick u 6 to place u 7 grip fall next execution…”

Section: Arm Pick-and-place Operationmentioning

confidence: 99%

Formal Verification of Logic Control Systems with Nondeterministic Behaviors

Alwi

Fujimoto

2013

IEEJ Journal IA

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This paper describes a formal modeling and verification of an arm pick-and-place system, in which nondeterministic behaviors of the arm state condition and timer function blocks are applied. We design an appropriate PLC program using a ladder diagram (LD) for the arm pick-and-place operation and apply in it a situation where the arm may drop the product or material being gripped because of an external force. In addition, the timer function blocks are used with formalization of their finite-state logical properties. We use an actual model of the arm to verify that safe operations are established for normal product pick-and-place, as well as when the product has fallen. In addition, we perform arm model verifications for five important temporal properties using the NuSMV model checker. We present two types of experiments to validate the safety of the designed LD program. We also verify that the nondeterminism that appears as a result of the system behaviors can be formalized and used to represent logical assumptions for the properties that need to be verified.

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“…A common solution is to use model checking, e. g. with the SPIN model checker; other approaches include abstract interpretation [17] or manually created, computer based proofs [18].…”

Section: Introductionmentioning

confidence: 99%

Model Checking Industrial Robot Systems

Weibmann

Bedenk

Buckl

et al. 2011

Lecture Notes in Computer Science

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Abstract. Modern production plants are highly automated complex systems consisting of several robots and other working machines. Errors leading to damage and stop of production are extremely expensive and must be avoided by all means. Hence, the state of practice is to test control programs in advance which implies high effort and comes with high costs. To increase the confidence into the control systems and to reduce the necessary effort, this paper proposes to use model checking to verify certain properties. It presents a compiler that can transform industrial robot programs into PROMELA models. Since the statements of the robot programming language can not be mapped directly into PROMELA statements, we apply compiler optimization techniques to close the semantic gap. In case of a specification violation the trace is mapped to the original context so that the robot programmer can reconstruct the problem. As a case study we applied the tool to verify the absence of collisions and deadlocks. We were able to detect one deadlock in a car-body welding station with 9 robots, correct the program and verify the correctness of the resulting system.

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Formalization and Verification of PLC Timers in Coq

Cited by 18 publications

References 8 publications

Parameterized Specification and Verification of PLC Systems in Coq

Parameterized Specification and Verification of PLC Systems in Coq

Formal Verification of Logic Control Systems with Nondeterministic Behaviors

Model Checking Industrial Robot Systems

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