Error diagnosis

In the event of undesirable operating behavior, an extended diagnosis may be necessary. Depending on the situation, this may include the following measures: ADS Trace, Wireshark Trace, log file, Memory Dump. A log function may also be available and useful on the client side. The appropriateness of the action depends heavily on the appearance of the behavior. Take another look at the software architecture of the TwinCAT OPC UA Server and compare it with the operating behavior. The following figure illustrates where the individual measures (described in more detail in the table) could be helpful.

Measure	Use case	Link
Client Log	Useful for recording extended protocol functions on the client side.	Please contact the manufacturer of the client for more information about its logging functions.
Wireshark Trace	Useful for examining communication between client and server.	https://www.wireshark.org/
Server Log	Useful for logging advanced server-side logging functions.	See chapter Logging in this documentation.
Memory Dump	It can be useful to create a Memory Dump in case the TwinCAT OPC UA Server is unexpectedly terminated. The tools required for this depend on the operating system.	Microsoft Debug Diagnostics
ADS Trace	Useful for examining the communication between server and PLC.	Beckhoff Download Finder (TF6010 TC3 ADS Monitor)

	Support The Beckhoff support department will be happy to assist you in implementing the appropriate measures.

The following table provides an overview of possible unexpected operating behavior and measures to resolve it.

Behavior	Measure(s)
An OPC UA client does not see the PLC namespace.	TF6100 Setup Version 3.x and older: this status indicates a missing license. Check whether you have activated a valid TF6100 license.
An OPC UA client is assigned the StatusCode 0x810e0000 when reading nodes.	TF6100 Setup Version 4.x: this status indicates a missing license. Check whether you have activated a valid TF6100 license.
The variables enabled via comments/attributes are not displayed in the OPC UA server.	Check whether the symbol file has been correctly transferred to the controller (e.g., check boxes in the PLC project), verify that it exists in the boot directory and that the path to the symbol file in the configuration file of the server refers to the correct symbol file. You can also use the DeviceState Node in the respective namespace to check any error messages that may have occurred. An entry is made here if the symbol file was not found. Also check that the comments/attributes are spelled correctly.
The server does not comply with the sampling rate/publishing interval required by the OPC UA Client.	OPC UA client/server is not a real-time protocol, i.e., there is no guarantee that the server will always meet 100% of the sampling rate or publishing interval required by the client. The available sampling rates and publishing intervals can be viewed in the server configuration file and modified if required (<AvailableSamplingRates> and <MinPublishingInterval>).
An OPC UA Client cannot connect to the server although the server is displayed in the Windows Task Manager. The error message "Host unreachable" (or similar) appears.	Check whether firewall settings prevent communication with the server. The server port must be open for incoming TCP communication so that a client can connect.
An OPC UA client sees the server's endpoints, but a connection with them fails with the error message "Host unreachable".	Check that the name resolution in your network is working properly and that the server is accessible under its host name. Even if the OPC UA Client apparently connects to the IP address of the server (e.g., opc.tcp://192.168.0.1:4840) to access the server's endpoints, the server always returns its own host name in its endpoints. If the client connects directly to one of the endpoints, it will use the host name of the server again. If the name resolution does not work, the connection fails.
An OPC UA Client sees the endpoints of the server, but a connection to a secure endpoint fails. The error message "BadSecurityChecksFailed" appears	Check whether the server trusts the client certificate. The required configuration steps can be found in section Certificate exchange. In this case, it must also be ensured that a signature hash algorithm of the SHA 2 group (SHA256, SHA364, SHA512) is used to sign the client certificate. If deprecated algorithms such as SHA1 are used, the TwinCAT OPC UA Server does not allow a connection.
When using an SQL server to store Historical Access information, the values are not added to the SQL database.	Check the access data to the SQL Server and verify that the SQL Server is also accessible in the network. Also make sure that you are using a "Big Windows" operating system on the TwinCAT OPC UA Server, since SQL Server cannot be used for Historical Access under Windows CE (although SQL Compact is OK).
When reading nodes, an OPC UA client receives the error message "BadDeviceFailure".	This is an indication that the associated ADS device cannot be reached, for example if no PLC program has been started. Check the connectivity with the ADS device and make sure that the appropriate runtime is active.
When reading nodes, an OPC UA client receives the error message "BadLicenseExpired".	This is an indication that no TF6100 license is active on the system or that it has expired. Please make sure that you have activated a TF6100 license on the device on which the server was installed.
Arrays are not displayed in the namespace with full resolution.	By default, arrays of simple data types are not displayed in expanded form in the namespace. However, individual array indices can still be addressed using the IndexRange function of OPC UA. An OPC UA Client should therefore support this function. If this is not the case, a radio button in the configuration file of the server can be used to display an array in expanded form, so that each individual array element can be addressed as a separate node. This radio button is described in the section Arrays.