# 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 cell data. In the context of the In-Sight OPC UA implementation, two types of OPC Tags exist:

- Job Tags

- 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: Represents tags that hold only boolean values.
- Floating point: Represents tags that hold only floating-point values.
- Integer: Represents tags that hold only integer values.

- Text string: Represents 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-Only or Read/Write. 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-Only access level means that you can only retrieve values of tags from the OPC UA client. Read/Write access allows you to set values of Job Tags inside the In-Sight Spreadsheet from the OPC UA client.