DESIGN OF AN ADAPTABLE LADDER EDITOR FOR PROGRAMMABLE LOGIC CONTROLLER

Ladder diagrams, which have been used for decades for describing relay circuits, are now being utilized for programming Programmable Logic Controllers (PLC). This is so because many practicing engineers and technicians are familiar with these diagrams, and fell comfortable working with them. The aim of this work is to design and implement a visual editor for ladder programming language that helps the programmer to write Ladder programs using PC environment, and when this editor connected with a real-time database it can be used as a ladder man machine interface to monitor a factory from outside field. This approach provides a good man machine interface than programming with mnemonic logic instruction. Normally the ladder programs have a very big size, so the editor has to find the most suitable method to store these programs and to navigate between the pages of these programs in a very fast response time. The designed editor is written using Visual Basic programming language and it is tested to write application programs for different industrial control processes and shows a very accepted results.