What is OPC UA Communication

Today’s article we will detail discuss about what is OPC UA Communication in laymen terms

We will see what is basic step will follow every or any OPC Server & client application to establish connection

What is OPC UA Communication

The OPC server is a program that translates the hardware communication protocol used by a PLC into the OPC protocol. The OPC client software is a program that connects to the hardware, such as an HMI. The OPC client communicates with the OPC server to receive data or send commands to the hardware

the communication speed of OPC UA is ~200ms, depending on server capabilities.

we will look at certificate management when securing communications between
your OPC UA client and an OPC UA server

OPC UA allows us to secure the communications between the client and server by signing and encrypting the messages between them

message signing allows the applications to confirm the source of the messages

encryption ensures the messages confidentiality

before establishing a communication channel the client and server will exchange certificates that include information about their identities and the necessary keys for managing the encryption

these certificates must be trusted by each side before the client can connect to the server

to secure communications between your Client and your OPC UA server

begin by configuring the Client OPC UA IO server

when you configure the OPC UA io server on automatically generates its own certificate
it also creates a series of directories within the user directory to hold trusted and untrusted certificates as well as its own certificate

in the communication security section of the io server setup page select the
security policy that’s right for your application

the OPC Client supports both basic 256 and basic 256 sha-256 security policies

then select the message security mode that is right for your application

the Client and the opcua server will attempt to connect and exchange certificates

however since the opcua server certificate is not yet trusted the connection attempt will fail
when we refresh the io server setup

once OPC UA communication can be established and the Client will be able to monitor
tags from the opc ua server

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