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After activating the session, all types of messages that are intended for object management in the address space of the OPC UA server can be swapped. In this step, the client creates a subscription with the parameters set on the communication station level for all stations within the communication line.
The monitored items should be then inserted into these subscriptions. They correspond with the instances of I/O tags, which contain the parameters defined in the address dialog window.
From this moment, the server informs the client about the changes in the monitored objects by
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| Parameter name | Meaning | Unit | Default value | ||||||
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| Type of used client (driver for OPC UA communication):
| Default Secure | Default | ||||||
| Session text identifier. Session identifier should be unique within the client instance, making it possible to search problems faster in the client or server logs. | String | Kom process | ||||||
| The channel must be reopened before this time limit elapses. If the time is exceeded, the channel will be closed and unable to change data. | hh:mm:ss | 01:00:00 | ||||||
| Any message should be changed between client and server before this time limit elapses. If it is not sent, the sources within the session that are kept on the server are released. The primary work of this parameter is to remove the sessions that became inactive because of some unexpected reason. | mm:ss | 01:00 | ||||||
| Type of authentication used with the OPC UA server. Supported types are:
| Anonymous / Username | Anonymous | ||||||
| If Authentication type = Username, then user name used in the authentication. If Authentication type = Certificate, then path to user certificate (e.g. D:\user_cert.der). | ||||||||
| If Authentication type = Username, then password used in the authentication. If Authentication type = Certificate, then path to user private key (e.g. D:\user_private_key.pem). | ||||||||
| Security policy (only for Client Type = Secure; for Client Type = Default a security policy None is used):
| None Basic128Rsa15 Basic256 Basic256Sha256 Aes128Sha256RsaOaep Aes256Sha256RsaPss | None | ||||||
| A mode of message security in OPC UA communication (only for Client Type = Secure; for Client Type = Default a mode of message security None is used):
| None Sign Sign & Encrypt | None | ||||||
| Identifier of preferred Security Policy (only for Client Type = Default for password encryption). If the OPC UA offers several security policies, it is possible to select a specific one according to the identifier sent by the OPC server (the identifier can be found from the logs). Examples of an identifier (text form is in parentheses): PolicyId: 30 (0) PolicyId: 31 (1) PolicyId: 75 73 65 72 6E 61 6D 65 5F 62 61 73 69 63 31 32 38 52 73 61 31 35 (username_basic128Rsa15) PolicyId: 75 73 65 72 6E 61 6D 65 5F 62 61 73 69 63 32 35 36 53 68 61 32 35 36 (username_basic256Sha256) | - | - | ||||||
| Waiting after the connection is broken before the connection is re-established. | mm:ss.mss | 00:10.000 | ||||||
| Waiting after an unsuccessful connection attempt. | mm:ss.mss | 00:02.000 | ||||||
| Waiting after an unsuccessful attempt to create monitored items. If it is zero, the attempt is not repeated. If it is non-zero, the attempt is repeated after the defined wait. | sec | 0 | ||||||
| It changes the number of information about communication. We recommend enabling the Extended/Full modes only when detecting the problems and debugging the communication. The "Full + Trace (Secure only)" mode is valid only for Client Type = Secure. | Normal/Extended/Full/ Full + Trace (Secure only) | Normal | ||||||
| The parameter defines the thread(s) that will send the debug info about the communication. | Receiving/Sending/Others treads/All threads | All threads |
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