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SCADA Write to OPCUA Input Registers
Posted: 23 Sep 2025, 15:30
by hydro-controls
While attempting to implement OPCUA, I cannot establish a good write method from external SCADA software to OPCUA registers. OPCUA input registers (via a virtual device module) do not appear to be writeable. If OPCUA output registers (same virtual device module) are write-enalbed in PiCtory, SCADA software can write to these registers. However, if a revpimodio2 object is running, any SCADA changes to output registers are overwritten at the end of each program cycle.
Re: SCADA Write to OPCUA Input Registers
Posted: 26 Sep 2025, 13:32
by tsm
Have you tried to experience from the tutorial from this link?
https://www.techsquare.co.th/tutorial/r ... a-gateway/
I followed some of the tutorials and can use OPC UA successfully.
They are the revolution pi expert from Thailand.
Re: SCADA Write to OPCUA Input Registers
Posted: 30 Sep 2025, 14:49
by hydro-controls
Thank you for sharing this. My configuration was built in a similar manner with one key exception. I have a revpimodio2-based python script running to control output based on user-input at a SCADA HMI. If the Python script is disabled, I can successfully write to OPC UA output registers. If the script is enabled, the SCADA system will write to OPCUA, but the affected register is immediately overwritten by the revpimodio2 object.