Behind-panel instrument symbol
A behind-panel instrument is in the control room but not on the panel face, so the operator does not normally use it.
What the behind-panel instrument symbol means
A behind-panel instrument is in the control room but not on the panel face, so the operator does not normally use it.
How it is drawn
A circle with a dashed horizontal line through the middle.
The behind-panel instrument symbol in each standard
Drawn as ISA 5.1 defines it, as on most US and international legends.
ISO 10628-2 does not cover instruments. On ISO-based P&IDs they are drawn as IEC 62424 PCE requests, or to ISA 5.1 on many international projects.
IEC 62424 has no separate symbol for this. Check the project legend.
German (DIN): PLT-Stelle hinter der Tafel. See DIN P&ID symbols.
Where you see it on a P&ID
For trip amplifiers, signal converters and relays in cabinets.
Tag codes
The behind-panel instrument is commonly tagged:
- PY
- FY
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 behind-panel instrument symbol look like on a P&ID?
A circle with a dashed horizontal line through the middle.
What is a behind-panel instrument used for?
A behind-panel instrument is in the control room but not on the panel face, so the operator does not normally use it. You will find it for trip amplifiers, signal converters and relays in cabinets.
What tag does a behind-panel instrument have?
It is commonly tagged PY, FY. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the behind-panel instrument symbol the same in ISA and ISO?
ISO 10628-2 does not cover instruments. On ISO-based P&IDs they are drawn as IEC 62424 PCE requests, or to ISA 5.1 on many international projects. Companies vary the details, so always check the legend sheets at the front of the P&ID set.
What is the behind-panel instrument called in German?
PLT-Stelle hinter der Tafel. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2 and DIN EN 62424.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016