Instrument Index Template
The master list of every instrument on a project, with the columns engineering teams expect: tag, service, type, line or equipment, P&ID, range, signal, system and links to the data sheet, hook up and loop drawing.
Download
- How to Use sheet with steps
- Template sheet, blank and ready
- Example sheet, filled in
- 2 built in formulas
- A4 landscape print setup
- Works in Excel, Google Sheets and LibreOffice
Preview of the Filled Example
This is the Example sheet from the download, so you can see exactly how the completed instrument index looks.
Instrument index
| Sr | Tag number | Service description | Instrument type | Line / equipment | P&ID number | Range min | Range max | Unit | Signal | System | Data sheet no | Hook up drawing | Loop drawing | Location | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | PT 1101 | Steam header pressure | Pressure transmitter | 8" ST 1101 | PID 100 02 | 0 | 16 | bar g | 4 to 20 mA HART | DCS | DS PT 01 | HU PT 01 | LD 1101 | Field | |
| 2 | PSH 1105 | Air receiver high pressure | Pressure switch | V 1105 | PID 100 05 | 0 | 16 | bar g | Dry contact | PLC | DS PS 01 | HU PS 01 | LD 1105 | Field | |
| 3 | TT 2101 | Reactor jacket outlet temperature | Temperature transmitter + Pt100 | 4" CW 2101 | PID 200 01 | 0 | 200 | °C | 4 to 20 mA HART | DCS | DS TT 01 | HU TT 02 | LD 2101 | Field | |
| 4 | FT 3101 | Feed flow to column | Magnetic flowmeter | 3" P 3101 | PID 300 01 | 0 | 120 | m³/h | 4 to 20 mA HART | DCS | DS FT 01 | HU FT 03 | LD 3101 | Field | |
| 5 | FV 3101 | Feed flow control valve | Control valve, globe | 3" P 3101 | PID 300 01 | 0 | 100 | % | 4 to 20 mA HART | DCS | DS CV 01 | HU CV 01 | LD 3101 | Field | |
| 6 | LT 4102 | Storage tank level | Radar level transmitter | T 4102 | PID 400 02 | 0 | 12 | m | 4 to 20 mA HART | DCS | DS LT 02 | HU LT 05 | LD 4102 | Field | |
| 7 | LSHH 4103 | Storage tank high high level | Vibrating fork switch | T 4102 | PID 400 02 | NAMUR | SIS | DS LS 01 | HU LS 01 | LD 4103 | Field | SIL 1 overfill | |||
| 8 | XV 4101 | Tank inlet shutdown valve | On/off ball valve | 6" P 4101 | PID 400 01 | 24 V DC SOV | SIS | DS XV 01 | HU XV 01 | LD 4101 | Field |
About the Instrument Index
The instrument index is the backbone document of instrumentation engineering. Every other document (data sheets, I/O list, cable schedule, loop drawings, hook ups) is generated from or checked against it. Keeping it complete and current saves hours of searching during construction and maintenance.
How to fill in this template
- Enter one row per instrument tag, following ISA 5.1 tag numbering.
- Fill the service description so an operator understands what is measured without opening the P&ID.
- Link each tag to its data sheet, hook up and loop drawing numbers; these columns become the document cross reference.
- Use the System and Location drop downs to keep values consistent, which makes filtering easy.
- Issue the index with each project revision and highlight changed rows.
What the formulas do
- Total tags counts every filled tag number.
Related tools
Frequently Asked Questions
What is an instrument index?
A list of every instrument on a plant or project with its tag, service, type, location, range, signal, system and references to other engineering documents.
Who prepares the instrument index?
The instrumentation engineer, usually starting from the P&IDs, and it is updated through the project.
Is the instrument index the same as the I/O list?
No. The index lists instruments; the I/O list lists signals to the control system. A single instrument can have several I/O points.
Learn more on the blog
Instrument index: 10 essential columns
A practical guide on instrumentationblog.in that explains the procedure behind this template and how engineers apply it on real plants.
Read Full Article