To the Group:
I had no idea that this grafcet thing would get such a big response. My efforts were to try to inform someone how to move back 2 steps in a control sequence. Grafcets have been around a long time. They are widely used in Europe but originally developed in France. There is a short article at the web site http://www.lurpa.ens-cachan.fr/grafcet/generalites/presentation_uk.html.
I have been gone during the holidays but as soon as I get a chance,(perhaps tonight) I will design a simple grafcet and logic and send it to the group. Please be patient. My intent surely was not to promote the concept but rather answer one question as to moving back and forth in "State Transition Logic". Another thing that you who are interested in this Grafcet is to do a search on "Grafcet" on the WWW. A lot of the information is written in french so you may need someone to translate it for you. Actually I did start the grafcet last night. I had my wife explain how she would like for a stove to work. She explained it, I wrote the grafcet and all I need to do is to write the logic. Good Luck & I hope everyone had a great Christmas and a Safe and Happy New
Year.

Tommy

 

Attached is the concept of Grafcets that I promised my of you. I hope it is helpful. I apologise for those that might not have Word 97. (I actually use AutoCad but thought that Word would be more popular.) You will need that to
take a look at it. I have written hundred of control schemes using this concept during the last 10 yrs. It has worked well for me. I hope you find some value in it but my guess is that most of you will never use it. Probably because it "takes more logic". But with scan times approaching Microseconds and Memory dirt cheap, who cares about space anymore. I am far more concerned with simplicity!

Tommy