In this paper, a method to divide a large-scale logic program is proposed. The hierarchical structure of the given logic program can be found by using graph theory. An illustrative example of elevator control program is shown as application of the proposed theory.

http://ieeexplore.ieee.org/iel5/9792/30882/01432211.pdf

Structure analysis of logic control programs

Inference method of interior coils for regeneration of control programs

Today, there are many needs to replace or maintain many plants built in the 1960s. However, it is difficult to replace or maintain them, because the documents of installed sequential control logic are seldom remain.

Therefore, we propose an automatic regeneration method(SPAIR) in order to solve this problem. SPAIR regenerates sequential control logic that is expressed on a ladder diagram from the input and output data of a target control unit and its supplementary specifications, which indicate the information about timers, etc. SPAIR consists of two parts, namely basic logic inferring engine and interior coil logic inferring engine. In basic logic inferring engine, time series data is compressed and translated into training data using the specifications. The training data are processed by inductive learning and transformed into control logic. In the interior coil logic inferring, the target logic of the interior coil is acquired by the selective attachment of logic parts.

Sequential Control Logic Inferring Method from Observed Plant I/O Data

The Inference Method of Interior Coils with Logic Parts Attaching Algorithm for Automatic Regeneration of Sequential Control Programs

1997 Index IEEE Robotics and Automation Magazine Vol. 4

Today, many plants built in the 1960s will probably be replaced or maintained. However, it is difficult to replace or maintain them because the installed sequential control logic documents are seldom still in existence. Therefore, we have proposed an automatic regeneration method (SPAIR) in order to solve this problem. SPAIR regenerates sequential control logic that is expressed on a ladder diagram from the input and output data of a target control unit and its supplementary specifications, which indicate the information about timers and interior coils. Time series data is compressed and translated into training data using the specifications. The training data are processed by inductive learning and transformed into control logic. We have developed the SPAR-System in order to edit all kinds of data, generate target logic for plants, and to easily verify the inferred logic simulation plant. Simulation experiments confirmed that control logic that is regenerated by SPAIR behaves in the same way as the installed control logic of a target plant model.

K. Doi

Papers

Automatic regeneration of sequence programs for operating plants