OPC Classic Plug-in

note

Note: If you want to use the function to read data from a redundancy server, you need the Enterprise license.

The following properties have to be specified for each set of OPC access data:

General

Property	Description
Name	This set’s name. The name will be shown in projection. Select a name you will recognize!
Host/IP	IP or host name of OPC Server’s computer.
OPC Server	OPC Servers accessible on computer specified under Host/IP. Select by drop-down
Update Rate (ms)	The update rate is the rate where the OPC server updates its data. Most OPC servers have an internal data memory and use the update rate to update the values in this memory. However, it depends on the OPC server which update rate is used. In the KepServer there is for example the setting Scan Mode. In the properties of the device you can set which scan rate should be used by the server and to what extent the update rate of the client is taken into account.
Dead Band (%)	The Dead Band property ensures that no transfer takes place from the OPC server to the client as long as the value does not exceed a certain threshold. This can be used to relieve the network. This function is optional and does not have to be implemented by all OPC servers.
Access Path	Access path on OPC Server

Redundancy

Property	Description
Activate Redundancy	Redundancy is enabled when the primary server is unavailable and (optionally) when the primary server's Alive item cannot be read or is set to 0.
Host/IP	IP or host name of OPC Server’s computer.
OPC Server	OPC Servers accessible on computer specified under Host/IP. Select by drop-down
Alive item	A specific node or tag that is monitored to ensure that the connection to the OPC server is still active. This field is used to periodically check the status of the server by reading the value of the specified "alive" element. If the value can be successfully read, it indicates that the server is still responding and the connection is healthy.

Advanced

Property	Description
Enable Asynchronous Writing	Determines whether asynchronous writing is used. This allows data points to be updated without having to wait for a response from the server before further actions can be performed.
Re-register on Bad Quality	After an error during reading, the connection to the data point is re-established.
Disable Change Notifications	Deactivates notifications when values are changed. This is necessary for servers with version 1 or version 2 because they do not support change notifications.
Array write mode	The following options are available for the array write mode: Use raw array: This writes the original array to the data point. Fill missing values with recent values: If values are missing, they are filled with those that were last available. Fill missing values with standard values: Here, the missing values in the array are overwritten with a default value. Note: The default value is always the default value of the respective data type. The default value for a string is “”.
OPC Read Mode	The OPC read mode defines how data is read out. The following options are available: OPC Router Cache: Data is preferably read from the OPC router cache. This minimizes network traffic, but can result in the data not being the most up-to-date, especially if the values in the data source change frequently. Asynchronous: All data from OPC transfer objects is requested asynchronously. This allows the OPC router to perform other tasks while waiting for a response, which can improve efficiency. Synchronous: With this option, data is read directly from the data source as far as possible. This option generates more network traffic, but provides the most up-to-date data. Please note that this option is currently only implemented in the OPC transfer object.
Allowed qualities	Here you can specify which data qualities are acceptable for the values to be read or written. In OPC UA, the data quality indicates the reliability and validity of the data.
Server Types	Manual type definition in the transfer objects to tell the OPC server which data types are expected.
DA Version	The version of the OPC DA specification of the server. The following options are available: Highest, V3, V2, V1 The version of your OPC server can be found in the corresponding manual.

note

Note: Pay attention to the firewall of the involved computers. Especially if the OPC-Server and the OPC-Router are running on different computers, it is not possible to use the firewall because of the dynamic port allocation via DCOM. If it is not possible to deactivate the firewalls, please contact inray.

Use the Access Path property to enter only the OPC items later when configuring the connection. This option is particularly useful if you only want to enter the data points during project planning.

To do this, create a separate OPC connection for each controller and define a unique access path in the OPC server, which you specify here.

If you need to connect different controllers with identically named data points, you can also use this variant, e.g. in combination with the connection templates. You would then enter the OPC connection as a variable in the template and assign it accordingly when instantiating the connection.