# \#opc-ua

**URL:** https://forumautomation.com/tag/opc-ua/78.md

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## [NODE-Red , OPC-UA, CODESYS , UA EXPERT](https://forumautomation.com/t/node-red-opc-ua-codesys-ua-expert/14179)

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**Author:** [@Abdullah\_Khanzada](https://forumautomation.com/u/Abdullah_Khanzada)\
**Replies:** 0\
**Last updated:** [June 6, 2026, 5:54am UTC](https://forumautomation.com/t/node-red-opc-ua-codesys-ua-expert/14179 "2026-06-06T05:54:32Z")

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Hi everyone, I am trying to read a simple Boolean variable from a CODESYS V3 PLC (SoftPLC on Windows) into Node-RED using node-red-contrib-opcua, but I am consistently getting undefinedas the payload, even though the se…

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## [How to Connect Siemens PLC with SCADA System via OPC UA?](https://forumautomation.com/t/how-to-connect-siemens-plc-with-scada-system-via-opc-ua/9608)

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**Author:** [@Ajmal\_ismail](https://forumautomation.com/u/Ajmal_ismail)\
**Replies:** 1\
**Last updated:** [October 15, 2021, 9:57am UTC](https://forumautomation.com/t/how-to-connect-siemens-plc-with-scada-system-via-opc-ua/9608 "2021-10-15T09:57:38Z")

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In this article, we will discuss how to configure a connection between Siemens PLC S7-1500 to SCADA system by using OPC-UA. What is OPC and Why is it necessary? OPC stands for Object Linking and Embedding, shortly call…

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## [QUaModbusClient: Modbus to OPC UA Gateway (Free)](https://forumautomation.com/t/quamodbusclient-modbus-to-opc-ua-gateway-free/9718)

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**Author:** [@juangburgos](https://forumautomation.com/u/juangburgos)\
**Replies:** 0\
**Last updated:** [August 10, 2021, 8:46am UTC](https://forumautomation.com/t/quamodbusclient-modbus-to-opc-ua-gateway-free/9718 "2021-08-10T08:46:58Z")

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