Adding a sensor
Step-by-step guide to registering a sensor asset and configuring its channels, field by field.
This page walks through registering a sensor asset and configuring its measurement channel(s), field by field. Every field described here is also explained by an info tooltip (ⓘ) directly in the UI — clicking a tooltip brings you back to the matching section on this page.
1. Create the asset
Go to Assets → New Asset, choose asset type sensor, and fill in name,
manufacturer/model, serial number, and (optionally) a datasheet and location.
Saving creates the asset with an auto-generated ID (e.g. OG-00042).
2. Add a channel
A sensor asset can have one or more channels — one per physical quantity it measures. Most
single-purpose sensors (a thermocouple, a pressure transmitter) have exactly one channel; a
multi-parameter probe might have several. On the asset detail page, use Add channel and
give it a Channel ID (a short label unique to this asset, e.g. CH1).
3. Configure the channel
Physical quantity
The physical quantity defines the type of measurement (e.g. temperature, pressure) and determines the applicable units and calibration procedures. Choose the one that best matches the sensor's primary measurement — this drives which units appear in every unit dropdown below.
Every physical quantity Open Gauge supports, with its available sensing technologies, its Type dropdown options (only pressure has one today — see Measurement type below), and its selectable display units:
| Physical quantity | Technology | Type (if applicable) | Units |
|---|---|---|---|
| Temperature | Thermocouple (J, K, T, E, N, R, S, B), RTD (PT100, PT1000, Other), Thermistor (NTC, PTC, Other), Infrared, Fiber Optic, Semiconductor, Bimetallic | — | °C, °F, K |
| Pressure | Strain Gauge, Piezoresistive, Piezoelectric, Capacitive, Inductive, Resonant, Optical, MEMS | Absolute, Gauge (relative) | Pa, kPa, MPa, bar, psi, hPa, atm, mmHg, inHg, inH₂O |
| Flow | Differential Pressure, Orifice Plate, Venturi, Turbine, Positive Displacement, Electromagnetic, Vortex, Coriolis, Ultrasonic, Thermal Mass | — | m³/h, L/min, gal/min, kg/h, g/min, lb/min |
| Level | Float, Hydrostatic, Capacitive, Conductive, Ultrasonic, Radar, Laser, Optical | — | mm, cm, m, in, ft, % |
| Humidity | Capacitive, Resistive, Thermal Conductivity, Chilled Mirror | — | %RH, g/m³, Dew Point °C, Dew Point °F |
| Force | Strain Gauge, Piezoelectric, Hydraulic, Pneumatic, Optical | — | N, kN, kgf, lbf |
| Torque | Strain Gauge, Magnetoelastic, Optical, Piezoelectric | — | N·m, kN·m, lbf·ft |
| Mass | Strain Gauge, Electromagnetic Force Restoration, Vibrating Tube, Piezoelectric | — | kg, g, mg, lb |
| Strain | Foil Strain Gauge, Semiconductor Strain Gauge, Fiber Bragg Grating, Capacitive | — | µε, m/m |
| Displacement | Potentiometric, LVDT, Inductive, Capacitive, Eddy Current, Laser, Optical Encoder, Magnetostrictive | — | nm, µm, mm, cm, m, in, ft |
| Angle | Potentiometer, Optical Encoder, Magnetic Encoder, Resolver, Inclinometer, MEMS | — | °, rad |
| Angular Velocity | Optical Encoder, Hall Effect, Magnetoresistive, Tachometer, MEMS Gyroscope | — | rpm, °/s, rad/s |
| Angular Acceleration | MEMS Gyroscope, Optical Encoder (derivative) | — | °/s², rad/s² |
| Velocity | Doppler Radar, Laser Doppler, Encoder Based, Pitot Tube, Ultrasonic | — | mm/s, m/s, km/h, mph, knots |
| Acceleration | MEMS, Piezoelectric, Piezoresistive, Capacitive, Servo Accelerometer | — | m/s², g |
| Sound Pressure | Condenser Microphone, Piezoelectric Microphone, MEMS Microphone | — | Pa, dB, dB(A), dB(C) |
| Voltage | Resistive Divider, Capacitive Divider, Hall Effect, Isolation Amplifier | — | V, mV, kV |
| Current | Shunt Resistor, Hall Effect, Current Transformer, Rogowski Coil | — | A, mA, kA |
| Resistance | 2-Wire, 3-Wire, 4-Wire, Bridge Measurement | — | Ω, kΩ, MΩ |
| Power | Wattmeter, Power Analyzer, Calculated (V×I) | — | W, kW, MW |
| Energy | Energy Meter, Smart Meter | — | Wh, kWh, MWh |
| Frequency | Crystal Counter, Reciprocal Counter, Optical, Magnetic Pickup | — | Hz, kHz, MHz, GHz, bpm |
| Capacitance | Bridge, Charge/Discharge, Resonant | — | F, µF, nF, pF |
| Inductance | Bridge, Resonant, Impedance Based | — | H, mH, µH |
| Impedance | Impedance Analyzer, LCR Meter | — | Ω, kΩ, MΩ |
| Magnetic Field | Hall Effect, Fluxgate, Magnetoresistive, NMR, SQUID | — | T, mT, µT, G |
| Electric Field | Field Mill, Electrostatic Probe, Capacitive Probe | — | V/m, kV/m |
| Radiation | Geiger-Müller, Scintillation, Semiconductor, Ionization Chamber, Proportional Counter | — | Gy, Sv, rem, Bq |
| Illuminance | Photodiode, Photoresistor, Lux Meter | — | lx, fc |
| Luminance | Imaging Photometer, Spot Photometer | — | cd/m² |
| Concentration | Electrochemical, NDIR, PID, MOS, Catalytic Bead, Zirconia, Mass Spectrometer | — | ppm, ppb, %, mg/m³ |
| pH | Glass Electrode, ISFET, Optical | — | pH |
| Conductivity | Contacting, Inductive, Toroidal | — | S/m, mS/cm, µS/cm |
| Salinity | Conductivity Based, Refractometer | — | ppt, PSU, g/L |
| Dissolved Oxygen | Galvanic, Polarographic, Optical / Luminescent | — | mg/L, % sat |
| ORP / Redox Potential | Platinum Electrode, Gold Electrode | — | mV |
| Density | Vibrating Tube, Hydrostatic, Coriolis, Pycnometer | — | kg/m³, g/cm³ |
| Viscosity | Rotational, Vibrational, Capillary, Falling Ball | — | Pa·s, cP |
| Moisture | Capacitive, Microwave, Infrared, Gravimetric | — | %RH, %, g/g |
| Particle Concentration | Optical Particle Counter, Laser Scattering, Condensation Particle Counter | — | particles/m³, particles/ft³ |
| Wind Direction | Vane, Ultrasonic | — | ° |
| Precipitation | Tipping Bucket, Weighing, Optical | — | mm, in |
| Blood Oxygen | Pulse Oximetry | — | % SpO₂ |
| Surface Roughness | Contact Profilometer, Optical Profilometer, Laser Scanning | — | Ra (µm), Rz (µm), Rt (µm), µm |
Keep this table in sync with PHYSICAL_QUANTITIES in apps/web/src/lib/sensor-options.ts —
update it whenever a new physical quantity, technology, or unit is added there.
Measurement type
Some physical quantities have more than one measurement mode. The clearest example is pressure: a sensor can report absolute pressure (relative to a vacuum) or gauge pressure (relative to atmospheric pressure). Where a physical quantity has defined options, a Type dropdown appears under Physical quantity; where it doesn't need one (e.g. temperature), the field is hidden entirely.
Measurement range & unit
Enter the channel's measurement range (min/max) and display unit. Once a range is set, every "% FS" (percent of full scale) option below becomes available, since a percentage needs a span to convert against.
Technology
The sensing technology (e.g. RTD, thermocouple, strain gauge) sits to the right of physical quantity — a purely descriptive field with no effect on calculations.
Output signal
The sensor's raw output — type, value range, and unit — sits directly under the measurable range, in the same min–max/unit column layout. This is what the sensor actually outputs electrically, which may differ from the physical unit (e.g. a 4–20 mA current loop representing 0–100 °C).
| Output signal type | Description | Units |
|---|---|---|
| Analog | A continuous electrical signal proportional to the measured value (e.g. a 4–20 mA current loop). | mA, A, V, mV, kV |
| Digital | An encoded/discrete output; unit options match the channel's own physical quantity rather than a fixed electrical unit. | Same units as the channel's physical quantity |
| Frequency | The measured value is encoded as a signal frequency. | Hz, kHz, MHz, GHz |
| Resistance | Output is a variable resistance proportional to the measured value (e.g. a platinum RTD element). | Ω, kΩ, MΩ |
| Capacitance | Output is a variable capacitance proportional to the measured value. | F, µF, nF, pF |
| Ratiometric | Output expressed as a ratio of the sensor's excitation voltage rather than an absolute value (e.g. a bridge-type load cell's mV/V output). | mV/V, V/V |
Keep this table in sync with OUTPUT_TYPE_OPTIONS/getOutputUnits in
apps/web/src/lib/sensor-options.ts — update it whenever a new output signal type is added
there.
Accuracy value
Maximum deviation between the sensor output and the true value. Smaller means more accurate. Choose % FS as the unit to express this as a percentage of the measurable range instead of an absolute value — see The "% FS" convention below. This is the manufacturer/nominal accuracy spec, and it's what Open Gauge compares a calibration's measured error against to decide pass/fail — see Decision rules.
Resolution
Smallest change in input the sensor can detect and represent in its output. Resolution feeds automatically into every calibration's uncertainty budget as a Type B (rectangular) contribution — see The uncertainty budget.
Uncertainty (±)
Quantifies doubt about the measurement result, expressed as ±value. This is the manufacturer's nominal/expanded uncertainty spec. It pre-fills a per-calibration "Sensor nominal accuracy" field in the calibration wizard (still editable there) as an optional Type B contribution to that calibration's uncertainty budget — opt-in, because folding it in unconditionally risks double-counting against the fit-residual term computed from the calibration's own data.
Drift rate
Rate at which the sensor output shifts over time without any change in the measured quantity. Purely informational on the channel — Open Gauge's own drift detection is computed from actual calibration history, not from this manufacturer spec; see Drift metrics.
Response time (ms)
Time for the sensor output to reach a defined percentage of its final value after a step input change.
Bandwidth (Hz)
Maximum frequency of input changes the sensor can accurately follow.
Calibration method
The procedure used to calibrate this channel — linking one here lets the calibration wizard pre-fill the right steps, equipment, and acceptance criteria for this specific channel.
Calibration role
A checkbox, "Reference standard" (default: unchecked/No). Check it to mark this channel as a reference standard, so it can be selected as the traceability reference when calibrating other assets against it — see Calibration overview for how internal calibrations use a reference asset.
The "% FS" convention
Accuracy, Resolution, and Uncertainty each pair a numeric value with a unit dropdown. That
dropdown offers the channel's compatible physical units (e.g. °C for a temperature channel)
plus, once Range min/max are filled in, a "% FS" option as the first choice. There's no
separate "accuracy type" field to set — picking a real unit (like °C) means the value is
absolute; picking % FS means it's a percentage of the range span, and Open Gauge converts it to an
absolute value internally (value/100 × (range_max − range_min)) wherever it's used in a
calculation.
After saving
Once a channel is saved, every filled-in value is visible directly in the channel list on the asset page — no need to re-open the edit form to check what was configured.
Next steps
With a channel configured, you're ready to run your first calibration — see Calibration overview, or work through a complete numeric example in Worked examples.