Programmable controller having a stored program with both machine language instructions and source code data
US5287548A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 29, 1988 |
| Grant date | Feb 15, 1994 |
| Priority date | — |
| Expiry date | Feb 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/15127
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A programmable controller governs the operation of a piece of equipment by executing machine language instructions compiled from a ladder diagram type control program. The control program as stored in the controller includes not only compiled machine language instructions, but also a tokenized version of the source code from which certain machine language instructions were compiled. The source code is provided only for those portions of the machine language program which cannot be easily decompiled to produce the corresponding source code. This program storage facilitates subsequent editing of the stored program via a terminal connected to the programmable controller. During the editing process, the original ladder diagram can be reconstructed from a combination of the machine language instructions and the tokenized version of the source code. In doing so, the machine language instructions, which have a one-to-one correspondence with the source code instructions, are decompiled using conventional techniques. However, the tokenized version of the source code is used to recreate the portions of the ladder diagram for which each machine language instruction does not have a unique one-…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.