Data link symbol
Also called Software link, Communication link
A data link is a software or digital communication connection between systems, such as a fieldbus or a link between the DCS and a PLC.
What the data link symbol means
A data link is a software or digital communication connection between systems, such as a fieldbus or a link between the DCS and a PLC.
How it is drawn
A thin line with small circles at intervals.
The data link symbol in each standard
Drawn as ISA 5.1 defines it, as on most US and international legends.
Signal lines are not part of ISO 10628-2. They come from IEC 62424 or ISA 5.1.
German (DIN): Datenverbindung. See DIN P&ID symbols.
Where you see it on a P&ID
Between control systems, packages and smart devices.
Tag codes
The data link is commonly tagged:
- ISA 5.1
Tag formats follow the project numbering procedure. For instruments, the letters follow ISA 5.1, explained on the instrument symbols page.
Related symbols
Frequently asked questions
What does the data link symbol look like on a P&ID?
A thin line with small circles at intervals.
What is a data link used for?
A data link is a software or digital communication connection between systems, such as a fieldbus or a link between the DCS and a PLC. Between control systems, packages and smart devices.
What tag does a data link have?
It is commonly tagged ISA 5.1. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the data link symbol the same in ISA and ISO?
Signal lines are not part of ISO 10628-2. They come from IEC 62424 or ISA 5.1. Companies vary the details, so always check the legend sheets at the front of the P&ID set.
What is the data link called in German?
Datenverbindung. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2.
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