Should I reconfigure HMI while I’m planning to swap PLC with the same unit and program?
Usually, you don’t have to change the HMI if you’re loading the same program and replacing a PLC with the same model. The main thing to remember is that particular network addressing criteria, tag databases, and protocol settings drive the HMI communication with the PLC. The HMI will keep operating as previously in the new PLC if they stay unchanged; no modification is required.
Usually via a specified communication protocol like Modbus, Ethernet/IP, or Profinet, the HMI interacts with the PLC. Along with the tag structure or data table specified in the PLC, it employs a device address, IP address, or node ID. The tag names, memory addresses, and data structures are retained when you load the same program into the new PLC. So, the HMI can still locate the same data at the anticipated sites.
There are, nevertheless, several significant factors to take into account:
The new PLC should be assigned the same IP address or node ID as the prior device. The HMI will not be able to communicate unless the address changes and it is updated.
Some PLCs have customizable communication settings. These ought to fit the prior setup.
Licensing or Handshake Problems: Occasionally, the HMI confirms the PLC hardware ID. Should this be implemented, a revalidation or minimum update might be necessary.
Though no changes are made, it is best practice to conduct a complete system check following PLC replacement to guarantee all HMI panels and commands respond properly.
Ultimately, HMI reconfiguration is usually not required when replacing a PLC with a similar device if the hardware, addressing, and program stay consistent.