Patent ID: 6895289

Claim:
A document management system comprising: a document storing and managing device for storing and managing documents which describe control software of a controller; and a software maintenance tool of the controller installed in a control system, said software maintenance tool being connected to the document storing and managing device through a communication line; wherein, when the software maintenance tool of the controller performs operation such as a change, a modification, an addition, and a deletion of the control software of the controllers the result of the operation is reflected in documents of control circuit software, which are stored and managed by the document storing and managing device, on a document sheet basis, and the documents stored in the document storing and managing device of the control software of the controller and software of the controller included in the control system are managed in synchronization with each other, thereby allowing the documents of the control circuit software, which are stored and managed by the document storing and managing device, to be referred to on the document sheet basis from the software maintenance tool.