Pneumatic signal line symbol
Also called Instrument air signal
A pneumatic signal line carries an air pressure signal between instruments, for example from a positioner to a control valve.
What the pneumatic signal line symbol means
A pneumatic signal line carries an air pressure signal between instruments, for example from a positioner to a control valve.
How it is drawn
A thin line with pairs of short diagonal slashes across it at intervals.
The pneumatic signal line 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): Pneumatische Signalleitung. See DIN P&ID symbols.
Where you see it on a P&ID
Between pneumatic controllers, positioners and actuators.
Tag codes
The pneumatic signal line 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 pneumatic signal line symbol look like on a P&ID?
A thin line with pairs of short diagonal slashes across it at intervals.
What is a pneumatic signal line used for?
A pneumatic signal line carries an air pressure signal between instruments, for example from a positioner to a control valve. Between pneumatic controllers, positioners and actuators.
What tag does a pneumatic signal line have?
It is commonly tagged ISA 5.1. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the pneumatic signal line 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 pneumatic signal line called in German?
Pneumatische Signalleitung. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2.
- In production since 2014
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