Thank you both for your comments. I am considering the engineering and fabrication of the board. And I understand that it will cost my company much for time in engineering to design an embedded system over just buying an off the shelf PLC. Since I think programming the two will roughly take about the same time, maybe the PLC is even faster to program since interfacing is pretty easy with the PLCs I currently use.

Program updating is not an issue; I actually do not allow customers to change the program themselves. So the only program updating would be for me to send them a newly programmed chip or even a new PCB.

Again thanks for your guys input, I understand that this question might not have been the best question for this forum, and do appreciate your feedback and apologize if somebody feels like I waste their time.

Please if anybody else has some comments I would greatly appreciate also as state before if anybody has a study that he or she would be willing to share it would be greatly appreciated too.

Thanks Richard