CodeSys OPC UA client Unable to Connect To OPC UA sever through Username and password

kiranbsiddaiah — Thu, 07 May 2026 08:27:51 -0000

And also we do not have any opc ua related license . Do we need to have a opc ua license to communicate with OPC UA server with username and password

CodeSys OPC UA client Unable to Connect To OPC UA sever through Username and password

kiranbsiddaiah — Thu, 07 May 2026 03:08:24 -0000

Hi,

I'm using codesys v3.5 sp21 software. I have downloaded the sample opc ua client project from https://content.helpme-codesys.com/en/CODESYS%20Examples/_ex_uacapi_example.html and i tested connecting to "prosys opc ua simulation server".

Through Anonymous connection it is connecting to server and can read data.

Later tried to connect using username and password.
First got a SECURITY_CHECKS_FAILED error, trusted the client certificate in the server and this issue resolved.
Next got an INVALID_CERTIFICATE error, trusted the server certificate in the client and this issue resolved.
After these two error it is not establishing the connection and not giving any error messages.

UAAsyncProp: UA.AsyncProperty := (tnTaskName:='UAClientTask', usiTaskPrio:=20, udiTaskInterval:=10000);
UAPolicy: UA.SecurityPolicy := (sPolicy:=UA.OpcUa_SecurityPolicy.OpcUa_SecurityPolicy_Aes128Sha256RsaOaep, eSecurity:=UA.SECURITY_MODE.SIGN_AND_ENCRYPT);
//UAPolicy: UA.SecurityPolicy := (sPolicy:=UA.OpcUa_SecurityPolicy.OpcUa_SecurityPolicy_None, eSecurity:=UA.SECURITY_MODE.NONE);
UAAuth: UA.UserNameAuth := (sUserName:=UAVars.sUser, sPassword:=UAVars.sPass);
UAClient: UA.Client := (
itfAsyncProperty:= UAAsyncProp,
//sClientName:= 'MyOPC UA client name', //default: ‘CODESYS OPC UA Client’
sURL:= UAVars.sURL,
sSession:= UAVars.sSession,
itfPolicy:= UAPolicy,
itfAuth:=UAAuth,
udiTimeout:= 100000
//,itfNamespaceArray:= UAVars.itfNamespaceArray //optional use
);
-----------------------------------------------------------------------------------------------------------------------

Please let me know if any additional information required.

Thank you...

Unable to Connect To OPC Ua server through UserName identity

kiranbsiddaiah — Wed, 06 May 2026 10:57:04 -0000

Hi Team, i'm using the codesys to create an opc ua client to read the data from "Prosys OPC UA server simulation" tool .. I can able to connect to the server with anonymous authentication ...
But when i tried to connect with user name authentication if fails to disconnect and does not return any errorID ... I have fixed security_check_failed error by trusting the client certificate on server side and also fixed invalid_certificate issue by trusting the server cetificate on client side .. After fixing these to error it fails to connect with NO_ERROR message.

And i also noticed an error message like "Demo mode for CmpOPCUAClient started. Will expire and stop!" in the device log tab .

please let me know the changes required to establish the connection ...

Recent posts by kiranbsiddaiah

CodeSys OPC UA client Unable to Connect To OPC UA sever through Username and password

CodeSys OPC UA client Unable to Connect To OPC UA sever through Username and password

Unable to Connect To OPC Ua server through UserName identity