Our PLC (Premium TSX573 Series with PL7Pro 4.2) for the Filter Process Control suddenly triggers a different output when you select an input. This has happen when we integrate it with Wonderware Scada. Although it has run for some time. The scada communicates with the PLC through Modbus, and some addresses were repeated meaning they might be triggered at the same time. We were supposed to expect an output signal from the output bus to trigger a relay to start a pump. We were running the program from the back-up PC but received error having communication issues time out. We tried replacing the CPU but still the same. The program resides in the memory card and maybe if we will replace it and reload new program might solve the problem. What do you think fellows?