What is an OPC Tag?
An OPC Tag is a symbolic name that can be applied to the spreadsheet cell of an In-Sight sensor or emulator. The tag can be visible to OPC clients so they can access the In-Sight spreadsheet cell data.
In the context of the In-Sight OPC Classic Server, two types of OPC Tags exist: Job Tags and Sensor Tags.
An OPC Tag can represent the following data types:
- Boolean
- Floating point
- Integer
- Text string
OPC Tag Naming Rules
OPC Tag names must adhere to the following rules:
- Tag names may not start with a numerical digit.
- Tag names may not contain spaces.
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Tag names may not be equivalent to spreadsheet cell names or have the form of spreadsheet cell names. For example:
a0
Invalid tag name (equivalent to a spreadsheet cell name)
G213
Invalid tag name (equivalent to a spreadsheet cell name)
c9100
Invalid tag name (has a form similar to a spreadsheet cell name)
10window
Invalid tag name (starts with a numerical digit)
MyTag
Valid tag name
AcqCounter_A0
Valid tag name
_a0
Valid tag name
A0_Counter
Valid tag name
- Tag names may not be equal to any of the predefined Sensor Tag names used by the In-Sight OPC Classic Server.
- Each OPC Tag name within a job file must be unique; duplicate tag names are not allowed.
- Tag names are case-sensitive. If you create an OPC Tag from within In-Sight Explorer, the corresponding OPC Tag referenced from the In-Sight OPC Classic Server must use the exact same upper and lower case characters. If the two names do not match exactly, a Configuration Error will result.