Instrument Datasheet.
An instrument datasheet is the per-tag specification document that records every parameter needed to procure, install, calibrate, and maintain a field instrument. It captures process conditions, instrument type, range, accuracy, materials of construction, electrical connections, certifications, and vendor information. Datasheets are the bridge between the I/O list, which tells you the tag exists and the purchase order, which buys the right hardware.
Three drawings included on a new account.
What Instrument Datasheet means.
An instrument datasheet is the per-tag specification that carries everything needed to buy, install, calibrate, and maintain one field instrument, and it is the document that turns a line on the instrument index into a purchase order. It consolidates data from several sources that the P&ID does not hold. The process conditions come from the heat-and-material balance, the instrument selection from the controls specification, and the model and wetted-material details from the vendor's proposal. A typical sheet records the service and area classification, the full process envelope, fluid, temperature, pressure, density, flow range, the sensor type and measured range, the output and communication protocol, the body and wetted materials, the end connection and enclosure rating with its hazardous-area certification, and the calibration and maintenance data, with ISA-20 providing the standard template per instrument type and most operators layering a house standard on top that can run to several hundred fields for regulated service. It is a controlled document, issued in stages through detailed engineering, for enquiry, then for purchase, then for construction with its revision tracked against the P&ID revision it answers to. What a reading of the P&ID set provides toward it is the upstream skeleton. The tag, the service, and the drawing reference captured on the instrument index, which is the spine the datasheet hangs the rest of its content on. The process, vendor, and calibration detail come from the engineering and supplier records, not the drawing.
What goes on a datasheet
Header. Tag, service, P&ID reference, area classification. Process data. Fluid, temperature range, pressure range, density, viscosity, flow range. Instrument specifics. Sensor type, vortex, mag, Coriolis for flow. Capacitance, radar, GW radar, hydrostatic for level. Etc. range, accuracy, output, 4-20 mA, HART, FF, PA, wetted materials, body materials, end connection, flanged, threaded, sanitary, enclosure rating, IP67, NEMA 4X, Ex d, e, i certifications. Calibration. Zero, span, linearity test interval. Vendor. Manufacturer, model, tag plate engraving, spare parts list.
Datasheet templates and the ISA-20 standard
ISA-20, ISA-TR20 standardizes datasheet templates per instrument type, control valve, flow transmitter, pressure transmitter, level transmitter, etc. Major operating companies layer their own house standards on top, often expanding to 200 plus fields per instrument for regulated industries. Datasheet generation is a controlled-document workflow. Datasheet revision tracks against the relevant P&ID revision and the engineering project schedule.
What each instrument type's datasheet has to carry that others do not
The common blocks (tag, service, line, area classification, materials, connections) are the same everywhere. These are the type specific entries that stop a datasheet from being answerable by a vendor.
| Instrument type | Process data the datasheet must state | Signal and output detail | Connection detail |
|---|---|---|---|
| Differential pressure transmitter on flow | Differential range at minimum, normal and maximum flow, plus fluid density and viscosity at flowing conditions | Analogue output with digital overlay, and whether the output is square root or linear | Manifold type, impulse line arrangement, and the primary element tag |
| Coriolis flow meter | Mass flow range, fluid density range, and the allowable pressure drop | Analogue, pulse and digital outputs, and which variable each carries | Line size, tube material, and the required orientation |
| Magnetic flow meter | Flow range and the minimum conductivity of the fluid | Analogue and pulse outputs, and empty pipe detection | Liner and electrode material, and the earthing ring arrangement |
| Control valve | Flow coefficient at minimum, normal and maximum flow, inlet and outlet pressure, and the allowable noise level | Actuator type, fail position, and the positioner signal | Body size and rating, trim material and characteristic, end connection |
| Pressure relief valve | The relieving scenario, the required capacity, the set pressure and the back pressure | Not applicable | Inlet and outlet size, orifice designation, and the valve type |
| Guided wave radar level transmitter | Measuring span, probe length, the dielectric constant of the medium, and any interface measurement | Analogue output with digital overlay | Nozzle size and standoff, and whether it is in the vessel or in a chamber |
| Temperature transmitter with an element | Range, element type, and the wiring configuration | Analogue output with digital overlay | Thermowell tag, insertion length and the process connection |
| Analyser | The component measured, the range, the expected sample matrix, and the sample conditioning duty | Analogue output plus a digital link for the full result set | Sample point tag and the fast loop arrangement |
| On and off valve with limit switches | Line size, pressure and temperature, and the required stroke time | Solenoid voltage, and the open and closed feedback signals | Body rating, end connection and the actuator mounting |
Datasheet field groups on an ISA-20 style form
ISA-20 and ISA-TR20.00.01 give a standard form per instrument type. The groups are the same across the forms; only the type specific block changes.
| Group | What it carries | Who fills it |
|---|---|---|
| Identification | Tag number, service description, P&ID number, line or equipment number | Instrumentation engineering from the P&ID |
| Process conditions | Fluid, flow, pressure, temperature, density, viscosity, phase, and corrosive components | Process engineering |
| Instrument requirements | Range, accuracy class, materials, connection size and rating | Instrumentation engineering |
| Signal and power | Output signal, supply, and the digital protocol if there is one | Instrumentation and control system engineering |
| Area classification | Zone, gas group, temperature class and the required protection concept | The hazardous area schedule |
| Installation | Mounting, hook-up detail number, and any special requirement such as heat tracing | Instrumentation engineering |
| Vendor block | Manufacturer, model, serial number and certificate references | The vendor, returned with the quotation and again with the equipment |
| Revision block | Revision, date, prepared, checked and approved | Document control |
Common questions
Where does datasheet data come from.
Are datasheets required for non-instrumented items like manual valves.
At what project phase are instrument datasheets issued for procurement.
Get the instrument datasheet template.
One ISA S20 form per sheet, section grouped, with the process and electrical blocks laid out to fill. Plain .xlsx.