Hi Crossbow,
Thank you for your reply. I got some more newbie question. We do not have the face mounted console thing. The battery is dead when it checked it. Is it safe to say that the program in the PLC is gone once the battery died out?
Correct me if I am wrong, but the difference between PLC and smart relay is that PLC can do arithmetic? Is it safe to say that if I do not have any analog inputs or outputs need, I can just use a smart relay instead of PLC?
Do you have other brands aside from Seimens that you can recommend that uses ladder? Something cheaper but gets the job done. I just need to get the relays, limit switches, and solenoid working together.
Are there any free software to program a PLC? Or we really need to buy the software from the company that made the PLC?