# OPC Tags

An OPC tag is a symbolic name that can be applied to the spreadsheet cell of a supported In-Sight vision system. The tag is visible to OPC UA clients, so they can access the In-Sight spreadsheet cell data. In the context of the In-Sight OPC UA implementation, two types of OPC Tags exist: Job Tags and System Tags.

Note: You can create a maximum of 250 OPC Tags.
Note: OPC/UA does not support Trigger Industrial Ethernet to trigger the vision system. Make sure to use Software Trigger when triggering through OPC/UA with TriggerManualAcquisition method.

An OPC Tag can represent the following data types:

- Boolean: Used to represent tags that hold only boolean values.
- Floating point: Used to represent tags that hold only floating-point values.
- Integer: Used to represent tags that hold only integer values.

- Text string: Used to represent tags that hold only text string values.

  Note:
  - Text strings support a maximum of 256 characters.
  - Text strings are sent to the OPC client in the Unicode representation of the text.

OPC Tags can have an access level of Read. The ability of OPC UA clients to read data from or write data to the In-Sight job file depends on the OPC tag access level. A Read access level means that you can only retrieve values of tags from the OPC UA client.