It's very sad to say, the developer was unknown person and NAMBA Co had been hired him and setup the system. Unfortunately NAMBA Co. closed and I didn't find any one who worked with them. Latterly system was dormant and nobody touched it. Luckily I had a standby A2USHCPU-S1 PLC and it help me to run the system. I believe that old A2USHCPU-S1 PLC program was corrupted and if I could download the program form the working PLC and reprogram that to old one or upload to a new A2USHCPU-S1 PLC. It will be safe for the future.
I need to learn and do it my self.
Please assist me.