E/S
Every machine, every process, every safety system starts with a sensor. A sensor translates a physical quantity — presence, temperature, pressure, distance, speed, vision — into an electrical signal the controller can act on. This guide covers every major industrial sensor technology in depth: operating principle, selection criteria, wiring, installation, failure modes, real brand references, and engineering calculations. From first contact with a proximity sensor to designing a multi-sensor safety architecture.
Choosing the wrong sensor wastes time, money, and creates maintenance nightmares. A systematic selection process eliminates 90% of bad choices before you open a catalogue. Start with the physical quantity, then narrow by environment, range, accuracy, and output type.
Answer the questions below. The wizard scores every technology and recommends the best options with reasons.
Step 1: Define the measurand (what physical quantity — presence, distance, temperature, pressure, flow?). Step 2: Define the target and medium (material, size, temperature, chemical compatibility). Step 3: Define the environment (IP rating, EMC, vibration, ambient temperature, ATEX zone). Step 4: Define the required performance (range, resolution, accuracy, response time, switching frequency). Step 5: Define the interface (output type, power supply, communication protocol, cable type). Only then open a catalogue.
// Sensor selection worksheet — fill before specifying
//
// MEASURAND:
// What to measure: [ ] presence [ ] distance [ ] temperature
// [ ] pressure [ ] flow [ ] level
// [ ] force/weight [ ] vibration [ ] vision
// TARGET / MEDIUM:
// Material: [ ] ferrous metal [ ] non-ferrous metal [ ] plastic
// [ ] liquid [ ] powder [ ] human body
// Size: _____ mm (minimum target dimension)
// Temperature of target/medium: _____ °C
// Chemically aggressive? _____ (which chemicals)
// ENVIRONMENT:
// Ambient temperature: _____ to _____ °C
// IP rating needed: IP _____
// ATEX zone: [ ] none [ ] Zone 2 [ ] Zone 1 [ ] Zone 0
// Vibration level: _____ g (IEC 60068-2-6)
// EMI sources nearby: [ ] VFD [ ] welding [ ] RF equipment
// Washdown pressure: _____ bar
// PERFORMANCE:
// Measuring range: _____ to _____ units
// Resolution required: _____ units
// Accuracy required: ± _____ % of span
// Response / switching frequency: _____ Hz or _____ ms
// Repeatability required: _____ mm or _____ units
// INTERFACE:
// Output: [ ] PNP NO [ ] PNP NC [ ] NPN [ ] push-pull
// [ ] 4-20mA [ ] 0-10V [ ] IO-Link [ ] SSI
// [ ] PROFINET [ ] EtherCAT [ ] CANopen
// Supply voltage: _____ V DC
// Cable / connector: _____ m, M12 / M8 / flying leadSensing distance (Sn): nominal value for a standard target at standard conditions — always verify with actual target. Switching frequency: maximum ON/OFF cycles per second — determines minimum detectable target transit time. Hysteresis: difference between switch-ON and switch-OFF points (prevents chatter at the boundary). Response time: lag between target change and output change — different from switching frequency (includes internal filter time). IP rating: IP6X = dust tight, IPX7 = immersion to 1m, IPX8 = continuous immersion, IP69K = high-pressure washdown.
| Specification | Typical values | What it limits | Test method |
|---|---|---|---|
| Nominal sensing dist. Sn | 1–40 mm | Maximum gap to target | Standard plate, reference cond. |
| Operating distance Sa | 0–0.81× Sn | Guaranteed operating zone | Measure actual switch distance |
| Hysteresis | 10–20% of Sn | Dead band around threshold | Approach then retract |
| Switching frequency | 100–10000 Hz | Minimum detectable transit time | Rotating disc test |
| Response time | 0.1–10 ms | Lag at single ON/OFF event | Oscilloscope, light barrier |
| Repeat accuracy | ± 1–10% of Sn | Precision of repeated triggers | 100 cycles, measure std. dev. |
// Key sensor spec calculations
//
// Minimum target transit time:
// t_min = target_size / target_speed
// e.g. 5mm target at 2 m/s: t_min = 0.005/2 = 2.5 ms
//
// Required switching frequency:
// f_min = 1 / t_min = 1 / 0.0025 = 400 Hz
// Add 50% margin: f_spec ≥ 600 Hz
//
// Hysteresis effect:
// Sensor switches ON at 8mm, OFF at 6mm
// Hysteresis = 8-6 = 2mm (20% of 10mm Sn — typical)
// For vibrating target near boundary: hysteresis prevents chatter
// For precise position detection: use small hysteresis or analog
//
// Correction factor for non-standard targets:
// Sn_actual = Sn_datasheet × correction_factor
// Correction factors (inductive, typical):
// Mild steel (Fe): 1.00 (reference)
// Stainless 304: 0.70
// Aluminium: 0.45
// Copper: 0.35
// Brass: 0.40
//
// Operating distance (Sa):
// Sa = 0 to 0.81 × Sn (guaranteed operating range)
// Sa = 0.81 × Sn to Sn (non-guaranteed zone — avoid)
// Sa > Sn: no switching guaranteedProximity sensors detect the presence or absence of an object without physical contact. They are the most common sensors in industrial automation — cheap, robust, fast, and available in every size and shape. Four main technologies: inductive (metal), capacitive (any material), magnetic (reed/Hall-effect), and ultrasonic (any solid or liquid surface).
Select target material and sensor size. See the actual sensing distance, hysteresis zone, and whether a standard sensor will work for your application.
Inductive sensors generate an oscillating electromagnetic field. When a metal target enters the field, eddy currents are induced, damping the oscillation. The electronics detect this damping and switch the output. Key advantages: completely sealed (no moving parts), immune to dirt, oil, water, and non-metallic objects, fast switching (up to 10 kHz), long life (> 10^9 operations). The sensing distance depends critically on target material and size. Always specify the material correction factor and minimum target plate size.
// Brand reference — inductive proximity sensors
//
// SICK (Germany) — sick.com
// IME08-1B5NSZW2S 8mm barrel, Sn=1.5mm, PNP NO, M8 connector
// IME18-08BPSZW2S 18mm barrel, Sn=8mm, PNP/NPN, IP67
// IM08-02BPSZW2K 8mm flat-face, flush, Sn=2mm
// Use for: general automation, food/bev (stainless housing)
// Balluff (Germany) — balluff.com
// BES 516-300-S272 18mm, Sn=5mm, PNP, cable, standard workhorse
// BES 516-325-E2-C High-speed, f=3000Hz, for fast counting
// BES M30MI-POC40B-BP2 30mm, Sn=22mm, long-range, PNP
// Use for: high-speed applications, large sensing distance
// Pepperl+Fuchs (Germany) — pepperl-fuchs.com
// NBB2-12GM50-E2 12mm, Sn=2mm, NAMUR output, ATEX Zone 0
// NJ10-18GM50-E2 18mm, Sn=10mm, NAMUR, Ex-certified
// Use for: ATEX zones, chemical plant, intrinsic safety
// ifm electronic (Germany) — ifm.com
// IF5704 8mm, Sn=1.5mm, IO-Link, diagnostics
// IF0086 18mm, Sn=5mm, IO-Link Master compatible
// Use for: IO-Link smart sensors, Industry 4.0 integration
// Omron (Japan) — industrial.omron.eu
// E2B-M12KN04-M1-B1 12mm, Sn=4mm, PNP, pre-wired
// E2E-X10ME1 30mm, Sn=10mm, NPN, M12 connector
// Use for: OEM machine builders, Asian export machines
// Keyence (Japan) — keyence.com
// EV-112M 12mm, Sn=4mm, ultra-small, NPN/PNP
// PR-G51N Long-range, Sn=40mm, for large metal
// Use for: tight spaces, high precision requirementsCapacitive sensors detect changes in the dielectric constant of material in their sensing field. Unlike inductive sensors (metals only), capacitive sensors detect virtually any material — plastics, wood, liquids, food products, powders, and the human body. Key application: level detection through tank walls (plastic or glass only — not metal). Sensitivity must be adjusted on-site for the specific material, as the dielectric constant varies greatly (air=1, water=80, oil=2–4, most plastics=3–4).
| Material | Dielectric const. ε_r | Detection difficulty | Notes |
|---|---|---|---|
| Water | 80 | Easy | Detect through thin plastic walls |
| PVC/PP | 3–4 | Medium | Adjust sensitivity on site |
| Wheat/grain | 5–6 | Medium | Bulk density affects ε_r |
| Cooking oil | 3 | Medium-hard | Close sensing distance needed |
| PE/PTFE | 2.3 | Hard | Max sensitivity, short range |
| Air | 1.0 | N/A (reference) | Background medium |
// Capacitive sensor — sensitivity adjustment guide
// Sensitivity = how far into the material the field penetrates
// Potentiometer or teach-in adjusts detection threshold
//
// Typical dielectric constants:
// Air: 1.0 → low sensitivity (background reference)
// Water: 80.0 → easy to detect through thin walls
// Cooking oil: 3.0 → needs higher sensitivity
// PET pellets: 2.8 → granular — adjust for bulk material
// Wheat grain: 5.5
// Wood (dry): 2–5
// PVC: 3.5
//
// Through-wall detection:
// Max wall thickness (plastic/glass): Sn / 3 (rule of thumb)
// 18mm sensor Sn=8mm: detects through walls up to ~2.5mm
// 30mm sensor Sn=15mm: detects through walls up to ~5mm
// Brand reference — capacitive sensors
//
// SICK
// CMB18-0-10K 18mm, Sn=10mm, PNP/NPN, IP67
// CM12-08NPP-KC0 12mm, Sn=8mm, flush, for food
//
// Pepperl+Fuchs
// CB12-30GM70-E2-V1 12mm, Sn=4mm, NAMUR, ATEX
// CBN15-30GX60-E2 15mm flat, Sn=15mm, large area
//
// ifm
// KI5002 Level detection, IO-Link, container
// KG5001 2-wire, 30mm, flush capacitive
//
// Balluff
// BCS M30B4-PSC80C-S04G 30mm, Sn=40mm, long range
//
// Keyence
// CZ-V21A Colour mark sensor (capacitive principle variant)
// CA-D200 Remote capacitive for special materialsUltrasonic sensors emit a sound burst (40–400 kHz) and measure the time-of-flight of the echo. They detect virtually any solid or liquid surface regardless of colour, transparency, or surface finish. Unlike photoelectric sensors, they work on transparent and highly reflective targets. Key limitation: blind zone (150–300 mm typically). The speed of sound in air changes with temperature (c = 331 + 0.6×T m/s at T°C), affecting accuracy — premium sensors include temperature compensation.
// Ultrasonic distance calculation
// c_air = 331.5 + 0.607 × T_celsius (m/s)
// At 20°C: c = 331.5 + 12.14 = 343.6 m/s
// At -10°C: c = 331.5 - 6.07 = 325.4 m/s
// Error without temp compensation:
// Δc = 343.6 - 325.4 = 18.2 m/s = 5.3% error over 30°C range
// At 1m distance: ±53mm error — significant!
// Brand reference — ultrasonic sensors
//
// Pepperl+Fuchs — market leader in ultrasonics
// UC2000-30GM-IUR2-V15 30mm, 200-2000mm range, analog+digital
// UB500-18GM75-U-V1 18mm, 35-500mm, PNP NO+NC, compact
// UC4000-L2-I-V15 Flat housing, for confined spaces
// UB4000-F42-I-V15 Large range 250-4000mm, 4-20mA
// Use for: bottle counting, liquid level, roll diameter
//
// Sick
// UM30-214113 30mm, 35-350mm, PNP/NPN, IP67
// UM12-11112 12mm, 30-120mm, M12, compact
// UC4-13348 Analog 4-20mA, 200-4000mm, temp comp
//
// Balluff
// BUS M18MI-POM-030-S92 18mm, Sn=30-300mm, PNP
// BUS R05KE-XAA-50-S92 5mm flat, 3-50mm, for tight spaces
//
// Microsonic (Germany) — microsonic.de
// pico+15/CZ/E/TC 15mm, 15-150mm, high precision ±0.15mm
// Extremely accurate and compact — industry referencePhotoelectric sensors use a light beam (typically infrared LED, 850–950 nm, or visible red laser) to detect objects. They work on virtually any material and over long distances. Three fundamental configurations — through-beam, retro-reflective, and diffuse — each with distinct strengths and weaknesses. Modern photoelectric sensors add intelligence: background suppression, colour differentiation, luminescence detection, and IO-Link diagnostics.
Excess gain is the ratio of available signal to minimum required. Must be > 1 to detect, > 2 for reliable operation. Increase with through-beam or reduce distance.
Through-beam (separate emitter/receiver): most reliable, longest range (up to 60 m), highest excess gain. Ideal for large objects and dirty environments. Requires wiring two units. Retro-reflective: single unit, uses a corner-cube reflector. Range up to 15 m. Risk: shiny targets reflect directly back (false signal). Polarised versions prevent this. Diffuse (proximity mode): single unit, detects light reflected from target itself. Easiest installation, shortest range (0.1–2 m). Very dependent on target colour and reflectivity.
// Brand reference — photoelectric sensors
//
// Sick — market leader worldwide
// WL18-3P430 Retro-reflective, polarised, 0.1-6m, IP67
// WT18-3P430 Diffuse, background suppression, 20-300mm
// WE18-P440 Through-beam pair, range 25m, IP67
// WTB8-3P2461 Miniature diffuse, 15mm housing, 5-100mm
// WTF12-3P2131 Fork sensor (through-beam in U shape)
// Use for: general factory automation, packaging lines
//
// Keyence — premium performance, excellent diagnostics
// PZ-G41N Diffuse, auto-teach, 700mm range, IP67
// PR-G51NP Retro-reflective, 7m, PNP, IP67
// GL-R08 Thrubeam, 8m, laser, very precise detection
// PZ-V31 Smart sensor, displays signal level, teach-in
// Use for: high-speed lines, difficult targets, colour detection
//
// Omron
// E3Z-T61A Through-beam, 15m, PNP/NPN switchable
// E3Z-R61A Retro-reflective, 4m, M12 connector
// E3Z-D61A Diffuse, 200mm, M12, IP67
// Use for: OEM, standard applications, Asian market
//
// Balluff
// BOS 18M-PA-1YD-S4 Retro-reflective, 5m, PNP NO/NC, M12
// BOS 18M-PA-RE10-S4 Through-beam emitter, 10m, M12
// BOS R02K-XXD-02-S4 Miniature retro, 2m, very compact
//
// Leuze (Germany) — leuze.com — specialist in photoelectric
// PRK 118/4D Polarised retro-reflective, laser, 9m
// HT 3C/4L.300-S12 Through-beam fork sensor, 300mm gap
// HRTU 420M.300 Long-range through-beam, 300m (outdoor)
//
// Banner Engineering (USA) — bannerengineering.com
// Q45 series Rugged, washdown, food industry variants
// EZ-BEAM Ultra-compact, M4 housing
// WORLD-BEAM General purpose, all 3 modes, value rangeColour sensors detect specific colours using white LED and RGB or multi-wavelength analysis. They compare reflected spectra to stored references and output a digital match signal. Used for label colour verification, cap colour sorting, and print mark detection. Luminescence (fluorescence) sensors use UV LED (365 nm) to excite fluorescent markers invisible under white light — used for verifying invisible security marks and fluorescent glues. Fork sensors (U-shaped through-beams) allow insertion of thin objects (labels, sheets, wires) without alignment.
// Colour sensor selection and calibration
//
// Key specs for colour sensors:
// Light source: white LED (broadband) or RGB LEDs
// Detection method: 3-channel (RGB) or spectrometer
// Switching outputs: 2-4 channels (each trained to one colour)
// Resolution: ΔE ≥ 1 (CIELab colour difference unit)
// Teach-in: static (press button) or dynamic (while moving)
//
// SICK Colour sensors
// CQ28-08PPK 28mm, 8mm spot, RGB, 2-channel, IP67
// CQ28-08PSBK Same but with background suppression
//
// Keyence Colour sensors
// CZ-V21AP Fibre-optic type, 3-colour RGB, 0.5ms resp
// IV2-G300MA Vision sensor for multi-colour detection
//
// DataLogic (Italy) — datalogic.com — strong in colour/code reading
// TL46-W-815 RGB colour, 4 outputs, 8mm spot, teach-in
//
// BANNER
// QC50 Color 3-channel colour sensor, IP67, ATEX option
//
// Luminescence sensors:
// Sick LUT9U-11114 UV LED, fluorescence mark detection
// Balluff BOH 2M-001 UV detector for adhesive bead detection
//
// Fork / U-shape sensors:
// SICK WF3-40E510 40mm fork gap, laser, edge detection, <0.01mm
// Keyence GL-R08 8mm gap, thin object detection, 50µm
// Pepperl+Fuchs GL10-RT/43a 10mm gap, label/film detectionPosition and distance sensors measure displacement or separation with continuous output. They span from simple potentiometers to nanometre-resolution interferometers. The right technology depends entirely on the required range, resolution, accuracy, environment, and whether absolute or incremental measurement is needed.
Configure your encoder and mechanical system. See linear resolution at the load, counting frequency at max speed, and whether SSI or incremental output is appropriate.
Move the target distance slider. See the analog output current, raw counts, and measurement quality indicators — exactly as a real laser displacement sensor outputs them.
Laser triangulation sensors project a laser spot onto the target. A position-sensitive detector (PSD) or linear CCD measures the angle of the reflected light — from which the distance is calculated via geometry. Range: 10–600 mm typical. Resolution: 0.5–50 µm. Accuracy limited by linearity (±0.1–0.5% FS). Not affected by target colour but strongly affected by surface reflectivity. Time-of-flight (ToF) laser sensors use pulsed or phase-shift measurement for ranges up to 300 m. Used in AGVs, warehouse logistics, and building automation.
// Brand reference — laser distance sensors
//
// Keyence — premium laser displacement
// LK-G32 20mm range, ±0.02% FS, sampling 50µs
// LK-G82 80mm range, 0.5µm resolution, high speed
// LK-H022 22mm, spot Ø55µm, for tiny targets
// IL-030 30mm range, 4-20mA output, compact 11mm wide
// IL-100 100mm range, analog, for machine tools
// Use for: thickness, gap, height, flatness measurement
//
// Sick
// OD Mini 28mm housing, 20-130mm range, 0.01mm res
// OD5000 Large range 50-5000mm, sub-mm resolution
// DT50-P111 Time-of-flight, 0.05-50m, ±1mm, analog
//
// Micro-Epsilon (Germany) — micro-epsilon.com — specialist
// optoNCDT 1220 17mm housing, 20-50mm range, 0.3µm
// optoNCDT 2300 High-speed, 49kHz sampling, 0.1µm res
// scanCONTROL 2900 Laser line scanner, full profile measurement
// Use for: extreme precision, R&D, quality control CMM-grade
//
// Wenglor (Germany) — wenglor.com
// CP24MHT80 0-400mm, 4-20mA, IP67, outdoor rated
// PNBC003 20-130mm, PNP NO+NC + analog, IO-Link
//
// Panasonic
// HL-G1 series High-accuracy profile, 30-600mm
// HG-C1050 50mm range, 10µm resolution, compactLinear encoders (optical or magnetic tape scales) measure absolute or incremental displacement by reading a graduated scale. Glass scales (optical): resolution to 0.001 mm, accuracy ±1–5 µm/m, used in CNC machine tools. Magnetic scales: robust, tolerant of coolant and chips, accuracy ±5–20 µm/m. LVDTs (Linear Variable Differential Transformer): AC transformer-based, fully sealed, no contact, resolution <0.001 mm, range up to 500 mm, extreme reliability for harsh environments. Magnetostrictive: floating magnet on rod, absolute, no wear, range to 7.6 m, used in hydraulic cylinders.
// Brand reference — linear position measurement
//
// Heidenhain (Germany) — heidenhain.com — CNC market leader
// LS 487 (glass scale) 0.001mm resolution, ±3µm accuracy
// LB 382C (steel tape) ±5µm, up to 3m, CNC machine tool
// LIDA 279 (magnetic) ±5µm, coolant resistant, heavy machines
// Use for: CNC machine tools, precision grinding, CMMs
//
// Renishaw (UK) — renishaw.com
// RESOLUTE absolute Sub-nanometre resolution, 1Vpp or BiSS-C
// FASTRACK magnetic ±5µm, IP68, machine tool standard
// SiGNUM 1µm resolution, stainless scale, IP64
//
// MTS Sensors (USA) — mtssensors.com — magnetostrictive leader
// Temposonics RH 0.5µm resolution, SSI/Start-Stop, 25-7620mm
// Temposonics EP Profile housing, hydraulic cylinders
// Temposonics GBS IO-Link, EtherCAT, fieldbus, smart factory
// Use for: hydraulic cylinders, linear actuators, presses
//
// Balluff
// BTL7-E500-M0300-B-S32 Magnetostrictive, 300mm, SSI, 1µm
// BTL5-A11-M0100-P-S32 100mm, analog 4-20mA, draw-wire
//
// SICK
// TML1000P Magnetostrictive, 100-5000mm, SSI/IO-Link
//
// TE Connectivity / TE Sensor Solutions
// MHR linear LVDT ±25 to ±500mm stroke, 0.1% FS accuracy
// HCA (half bridge LVDT) ±2.5mm, high resolution, compactRotary encoders convert shaft rotation into electrical signals. Incremental encoders output A/B quadrature pulses (and Z index) — the controller counts pulses to determine relative position. Absolute encoders output a unique code for every shaft position — they know their angle at power-on without homing. Single-turn absolute: 0–360°. Multi-turn absolute: stores full revolution count (Wiegand effect or battery). Resolution: 1024 to 16,777,216 positions per revolution (1–24 bits). Interface options: HTL (push-pull), TTL (RS-422), SSI, EnDat, BiSS-C, Hiperface, CANopen, PROFINET.
// Brand reference — rotary encoders
//
// Heidenhain — absolute encoder market leader
// ROC 425 (single-turn) 25-bit, EnDat 2.2, ±30 arcsec
// ROQ 437 (multi-turn) 25+12-bit = 37-bit total, EnDat 2.2
// ERN 1387 (incremental) 5000 PPR, TTL, ±10 arcsec, servo
// Use for: servo drives, precision machine tools
//
// Sick
// AFS60A-S1AA524288 Absolute, 29-bit SSI, solid 60mm shaft
// DBS60E-TECAK00720 Incremental, 720 PPR, HTL, IP67
// AFM60A (multiturn) 12+18-bit, SSI, Profibus, EtherNet
//
// Baumer (Switzerland) — baumer.com
// BMMV 58 Multiturn, IO-Link, EtherCAT, flexible comm
// EIL580P Incremental, 4096 PPR, push-pull, IP67
// HOG86 Heavy-duty, hollow shaft, 10000 PPR
// Use for: motors, conveyors, food/bev (stainless)
//
// Pepperl+Fuchs
// RVI58N-032AGT8-01024 58mm, 1024 PPR, NPN, ATEX versions
// AVM58N-011AGT0BN Absolute, SSI, 13-bit, IP67
// Use for: ATEX zones, standard automation
//
// Lika (Italy) — lika.biz
// I59-H-10000ZCU416 58mm, 10000 PPR, HTL, IP67, heavy duty
// AM58 (absolute) 13-bit SSI or PROFIBUS, compact
// Resolution vs accuracy:
// 1024 PPR → 0.352° per pulse (coarse)
// 8192 PPR → 0.044° per pulse
// 1 048 576 PPR (20-bit absolute) → 0.000343° = 1.23 arcsecProcess sensors measure the physical state of a medium — liquid, gas, or solid — rather than the position of a machine component. They feed PID control loops, safety shutdown systems, and process monitoring. Accuracy, calibration, chemical compatibility, and SIL rating are the dominant selection criteria.
Select your process variable and medium. Get the recommended measurement technology, accuracy class, and a brand shortlist.
Adjust hot junction temperature and ambient (cold junction) temperature. See the measured EMF with and without CJC correction and the resulting temperature error.
Industrial temperature measurement uses a sensing element (PT100 RTD, thermocouple, or thermistor) connected to a transmitter that outputs 4–20 mA with optional HART. The transmitter handles the mV-to-mA conversion, cold junction compensation (for thermocouples), linearisation, and HART communication. DIN-rail transmitters accept any sensor type via jumper or software configuration. Head-mounted transmitters mount directly in the terminal head of the temperature sensor assembly.
// Brand reference — temperature transmitters
//
// Endress+Hauser (Switzerland) — endress.com — process automation leader
// TMT82 (DIN rail) Universal input: RTD/TC/mV/Ω, HART 7
// Accuracy ±0.1°C, 2× redundant inputs
// TMT162 (head-mount) PTB/IECEx, compact, HART, IO-Link
// iTHERM TrustSens Self-calibrating RTD sensor with drift alarm
// Use for: process industry, chemical, pharma, food
//
// Siemens
// SITRANS T (series) TF280, TF320, TF420 — head and rail mount
// SITRANS TR420 2-wire, HART, universal input, ±0.1°C
// Use for: Siemens PCS 7 / TIA Portal integration
//
// Yokogawa (Japan)
// YTA110/310/320/510 Universal transmitter, HART/FOUNDATION
// YTA70 Compact, head-mount, ±0.5°C
// Use for: oil/gas, refinery, chemical
//
// WIKA (Germany) — wika.com — specialised measurement
// T17.310 PT100 + transmitter, ±0.1°C, compact
// T32.100 Compact head transmitter, HART, SIL 2
// Use for: standard industrial, ATEX options
//
// Sensor element manufacturers (supply elements to above):
// Heraeus (Germany) PT100/PT1000 platinum elements, IEC 60751
// JUMO (Germany) Thermocouples, RTDs, complete assemblies
// TC Ltd (UK) Custom assemblies, high-temperature TCPressure transmitters are the most commonly specified process instrument. Every hydraulic system, compressed air circuit, and process pipe needs pressure monitoring. The piezoresistive Wheatstone bridge is universal for gauge and absolute measurement. Capacitance cell (SITRANS P DS III, EH PMC71) provides ±0.1% accuracy for DP and high-line pressure applications. For clean, non-aggressive media: any technology. For aggressive media: diaphragm seal (chemical seal) assembly with fill fluid (silicone, glycerol, or fluorinated oil).
// Brand reference — pressure transmitters
//
// Endress+Hauser
// PMC51 (gauge) 0.05% accuracy, stainless, HART, -1-40 bar
// PMP51 (absolute) 0.05% FS, ceramic cell, ATEX, SIL 2
// PMD55 (differential) 0.065% FS, dual compartment, HART 7
// PMP71 (high pressure) up to 700 bar, flush diaphragm
// Use for: process industry standard, SIL applications
//
// Siemens
// SITRANS P 220 0.2% FS, 4-20mA, compact, -1 to 400 bar
// SITRANS P 320 0.1% FS, HART, PROFIBUS, SIL 2
// SITRANS P DS III 0.065% FS, delta-sigma capacitance cell
// Use for: Siemens process systems
//
// Yokogawa
// EJA110E (DP) 0.04% FS, resonant silicon, 10 year stability
// EJX110A (DP) 0.04% FS, MWP 16 MPa, SIL 2 certified
// Use for: critical process, long-term stability
//
// WIKA
// S-10 (OEM/compact) ±0.5% FS, stainless, -1 to 1000 bar
// S-20 (standard) ±0.25% FS, 4-20mA, M12 or cable
// Use for: machine builders, general industrial, cost-sensitive
//
// Keller (Switzerland) — keller-druck.com
// Series 21Y OEM piezoresistive, -1 to 1000 bar, ±0.1%
// PR-21SR Submersible level probe, 0-2 to 200m H2O
// Use for: hydraulics, water systems, OEM integration
//
// Vega (Germany) — vega.com — level specialist
// VEGABAR 82 Process gauge, ceramic measuring cell, SIL 2
// VEGADIF 85 Differential, for flow/level, SIL 2Flow measurement is the most complex instrument category — no single technology suits all applications. Electromagnetic (conductive liquids), Coriolis (mass flow, high accuracy), Vortex (steam, gas, liquid), Ultrasonic (clamp-on, no contact), Differential Pressure (orifice, Venturi), Turbine (clean liquids), Positive Displacement (high viscosity), Thermal Mass (gas). The selection depends on: medium type, flow range, accuracy requirements, pressure and temperature, and whether mass or volumetric flow is needed.
| Technology | Accuracy | Media | Moving parts | Best for |
|---|---|---|---|---|
| Electromagnetic | ±0.2–0.5% | Conductive liquid | None | Water, wastewater, slurry |
| Coriolis | ±0.05–0.1% | Any fluid | None | Mass flow, custody transfer |
| Vortex | ±0.75–1% | Liquid/gas/steam | None | Steam, compressed air |
| Ultrasonic (clamp) | ±0.5–2% | Clean liquid | None | Non-invasive, retrofit |
| Turbine | ±0.5% | Clean liquid | YES | Fuel, clean water, lab |
| Thermal mass | ±1–2% | Gas only | None | Compressed air, natural gas |
| Positive displ. | ±0.1–0.5% | Viscous liquids | YES | Fuel oil, custody transfer |
// Brand reference — flow meters
//
// ELECTROMAGNETIC (conductive liquids, conductivity > 5µS/cm)
// Endress+Hauser Promag 10/50/55/H/P/W
// Promag 10D: 0.2-3 m/s, compact, water/wastewater, cost-effective
// Promag 55S: food/pharma (tri-clamp), 3-A certified
// Promag P: aggressive chemicals, PTFE lining, Hastelloy
// Siemens Sitrans FM MAG 5000/6000/8000
// MAG 5100: DN3-DN3000, ±0.4% accuracy, PROFIBUS
// ABB ProcessMaster FEP300/630: ±0.2%, various linings
// Krohne Optiflux 2000/4000: DN2.5-DN3000, ±0.3%
// CORIOLIS (mass flow, any fluid, high accuracy)
// Endress+Hauser Proline Promass 83F/X
// ±0.1% mass accuracy, density measurement, -200 to +400°C
// Siemens SITRANS FC430: ±0.1% mass, bidirectional
// Krohne OPTIMASS 7300: twin-tube, high pressure
// Micro Motion (Emerson): ELITE series, ±0.05% mass
// VORTEX (steam, gas, liquids, high temperature)
// Endress+Hauser Prowirl 72/200
// Steam/gas/liquid, -200 to +450°C, ±0.75% velocity
// Siemens SITRANS FX300: saturated/superheated steam
// Yokogawa YEWFLO: steam metering, power plants
// ULTRASONIC CLAMP-ON (no pipe cutting, portable)
// GE Sensing / Panametrics PT878: clamp-on, DN15-DN6000
// Keyence FD-Q: compact clamp-on, 0.5-4m/s
// Endress+Hauser Proline Prosonic Flow 93T: permanent
// Flexim (Germany): FLUXUS ADM7407, ±0.5% non-invasive
// THERMAL MASS (gas flow, low flow)
// Bronkhorst (Netherlands): EL-FLOW series, ±0.5% FS gas
// Alicat Scientific: MS series, fast response, PROFIBUS
// SICK: FLOWSIC600, natural gas, custody transferLevel measurement covers a huge range: from a simple float switch to a 40 m radar measurement in a crude oil tank. Technologies: Float switch (simple, reliable for on/off), Pressure transmitter (submersible or impulse line), Guided Wave Radar (GWR, IEC 61511 SIL 2, for foam/vapour/agitated surfaces), Non-contact radar (GHz, 26 GHz or 80 GHz — penetrates vapour, foam), Ultrasonic (non-contact, lower cost, affected by vapour), Vibrating fork (point level, blockage detection), and Capacitance (solids and liquids).
// Brand reference — level sensors
//
// NON-CONTACT RADAR (best for process vessels)
// Endress+Hauser Micropilot FMR50/51/54/57
// FMR57: 80GHz, ±1mm accuracy, foam/vapour immune, SIL 2
// FMR54: 4-wire FMCW, -40 to +130°C, 40m range
// Siemens SITRANS LR560: 78GHz, 30m range, hygienic
// Vega VEGAPULS 64/69: 80GHz, ±1mm, SIL 2 optional
// Krohne OPTIWAVE 8300/8400: 26GHz, viscous products
// GUIDED WAVE RADAR (vessels with obstacles, agitation)
// Endress+Hauser Levelflex FMP50/51/54
// ±2mm accuracy, rope/rod/coaxial probe, SIL 1-3
// Siemens SITRANS LG250: guided microwave, SIL 2
// Vega VEGAFLEX 81: GWR, SIL 2, foam tolerant
// ULTRASONIC (storage tanks, open channels, non-contact)
// Endress+Hauser Prosonic S FMU95: 15m, 0.3% FS, HART
// Siemens SITRANS LU28: 5m compact, 4-20mA, IP68
// Pepperl+Fuchs VEGASON: large range, open channel
// VIBRATING FORK (point level, overfill protection)
// Endress+Hauser Liquiphant M FTL51: SIL 1, liquids
// Vega VEGASWING 51: SIL 2, liquids and solids
// Siemens SITRANS LVL100: fork, liquids, SIL 1
// SUBMERSIBLE PRESSURE (wells, tanks, wastewater)
// Keller 36XiW: -1 to 200m H2O, ceramic, SDI-12/HART
// WIKA LMT: stainless, IP68, 4-20mA, 0-200m
// Vega VEGAWELL 52: 0-40m, HART, food/pharmaBeyond standard I/O sensors, modern automation relies on vision systems for quality verification, safety scanners for area protection, and specialised sensors for vibration, load, and gas detection. These systems are increasingly intelligent — they contain embedded processors, communicate over Ethernet, and generate structured data rather than simple ON/OFF signals.
Adjust detection rate and false positive rate. See the confusion matrix, parts per million (PPM) escapes, and cost impact for a production line.
Click inside the scan area to place a "person" and see how the scanner zones respond. Drag the warning and protective field radii.
Machine vision systems capture images and extract information: presence/absence, dimensions, position, colour, barcode, OCR, surface defects. Smart cameras have the processor integrated with the sensor — no separate PC required. Vision sensors are simplified smart cameras for common tasks (presence, shape, colour match). Full vision systems (multi-camera, complex algorithms, AI inference) run on industrial PCs with frame grabbers.
// Brand reference — machine vision
//
// Keyence — market leader in smart cameras
// IV2-G150MA Smart camera, 5MP, 40mm lens, GigE, AI
// IV2-G300MA 8MP, AI pattern matching, 0.01mm accuracy
// CV-X series Full vision system, multi-camera, 1000fps
// XG-X2000 Ultra-high speed, semiconductor inspection
// Use for: presence check, OCR, barcode, 100% inspection
//
// Sick
// Inspector PIM60 Smart camera, GigE, HALCON embedded
// VSIC Vision Sensor Simple shape/brightness detection
// Trispector P1000 3D vision, laser triangulation + camera
//
// Cognex (USA) — cognex.com — premium AI vision
// In-Sight 2000 Smart sensor, 0.5MP, neural network
// In-Sight 9000 8MP, 60fps, deep learning, GigE
// DataMan 470 Barcode reader, 360° decode, IP65
// VisionPro software PC-based, any camera, PatMax algorithm
// Use for: pharmaceuticals, automotive, electronics inspection
//
// Omron
// FH series PC-based vision, up to 8 cameras
// FQ2 (smart camera) 0.3MP, colour, ethernet, teach-in
//
// DataLogic
// A20 smart camera GigE, CMOS, 5MP, industrial housing
// Matrix 410N 2D Barcode reader, area imager, DPM
//
// MVTec (Germany) — mvtec.com
// HALCON Algorithm library, industry standard
// MERLIC No-code vision, drag-drop setupSafety laser scanners detect persons in programmable protective fields without physical guards. They scan a 270° arc, generate a 2D point cloud, and compare to configured protection zones. When a person enters the protective field, the OSSD (Output Signal Switching Device) safety outputs go LOW, triggering a stop. Light curtains (safety light grids) use a vertical array of through-beams to protect a fixed opening — faster response (<10 ms), simpler, but fixed geometry.
// Brand reference — safety sensors
//
// SICK — safety scanner market leader
// microScan3 Core 275° scan, 5.5m protective field, SIL 2/PLd
// nanoScan3 Core 275°, 3m, ultra-compact, EFI-pro
// S3000 Expert 275°, 7m, 70 configurable fields, PLd
// deTec4 (light curtain) 14mm resolution, PL e SIL 3, muting
// C4000 Advanced Light curtain, 30/40/50mm, finger/hand/body
// Use for: collaborative robots, access protection, AGVs
//
// Pilz (Germany) — pilz.com — safety system specialist
// PSENscan 275°, 5.5m, EFI-Bus, PSS 4000 integration
// PSENopt II (curtain) 14-30mm res, PLe, PROFINET Safety
// Use for: Pilz PNOZ/PNOZmulti safety relay systems
//
// Keyence
// SZ-V series 270°, 8.0m, sub-100ms, standalone logic
// SZ-04M Compact, AGV, mobile applications
// GL series (curtain) 14mm, PLe, easy wiring
//
// Leuze
// RSL 400 (scanner) 270°, 8.25m, PLd, 4 simultaneous fields
// MLC 500 (curtain) 14-90mm, PLe SIL 3, IP65
//
// OMRON
// OS32C (scanner) 270°, 4m, USB config, PLd
// F3SG-RA (curtain) 14-50mm, PLe, cascade connectionVibration sensors (accelerometers, velocity sensors) monitor machine health — bearing frequencies, imbalance, resonance. Integrated IEPE (ICP) accelerometers are the industrial standard: built-in amplifier, single coaxial cable, 4 mA constant current power. Force/torque sensors use strain gauge bridges for direct force measurement on test rigs, robots, and assembly machines. Gas detectors (electrochemical for toxic gas, catalytic bead for flammable gas, infrared for CO2/CH4) are mandatory in confined spaces and chemical plants. Energy harvesting sensors require no wiring — they power themselves from vibration, light, or thermal gradient.
// Brand reference — specialist sensors
//
// VIBRATION / CONDITION MONITORING
// Brüel & Kjær (Denmark) / HBK — bruel-kjaer.com
// 4507 B (IEPE) 100mV/g, 0.3Hz-10kHz, general purpose
// 4533-B (ICP) 100mV/g, miniature, M6 base, IP66
// Use for: machine monitoring, R&D, structural analysis
// PCB Piezotronics / MTS (USA) — pcb.com
// 352A60 100mV/g, IP67, side-exit M8 connector
// IMI 682A06 Wireless, Bluetooth, battery, IoT
// SICK
// SPX series Triaxial, 4-20mA + digital, IO-Link
// Wilcoxon / Amphenol
// 793L Velocity sensor 10mV/mm/s, industry standard
// LOAD CELLS / FORCE SENSORS
// HBM (Germany) — hbm.com — load cell market leader
// Z6 (single point) 0.5-50 kg, C3 accuracy, 0.02% FS
// PW15 (platform) 10-500 kg, platform scale
// HBM S2M (tension/comp) 500N-200kN, inline, ±0.1%
// Kistler (Switzerland) — kistler.com
// 9253B (3-axis) 3-axis force plate, piezoelectric
// 9139AA Torque/force combo, robot integration
// GAS DETECTORS
// Dräger (Germany) — draeger.com — safety leader
// Polytron 6000 Electrochemical, 4-20mA, HART, ATEX
// Polytron 8100 Pellistor catalytic, flammable gas
// TransIR Infrared, CO2/CH4, no oxygen needed
// Honeywell
// MIDAS transmitter 6 sensor options, HART, SIL 2 certified
// Sensepoint XRL Pellistor, 4-20mA, ATEX Zone 1/21
// MSA (USA)
// Ultima XIR (IR) Flammable gas, 5 year sensor life
// Ultima X5000 Electrochemical + IR combo
// WIRELESS / BATTERY-FREE
// Balluff
// BTF wireless IO-Link wireless, up to 10m, 125ms cycle
// ifm
// AL1000 (IO-Link W) IO-Link Wireless master, 24V, Class A
// WIKA
// TW-20 wireless Temperature, WirelessHART, 10 year batterySwitching frequency, CJC, signal standards, NAMUR, radar, flow technology — all real engineering questions used in professional assessments.
You must detect a 6 mm diameter steel pin passing a fixed point at 3 m/s. Which sensor type and minimum switching frequency is required?
A vision sensor correctly identifies 97% of parts and incorrectly rejects 3% of good parts. What are these metrics called?
A laser distance sensor (triangulation) has a measuring range of 40–150 mm and an output of 4–20 mA. The PLC reads 18.3 mA. What is the measured distance?
Why must a thermocouple measuring circuit always include Cold Junction Compensation (CJC)?
An ultrasonic distance sensor has a blind zone of 150 mm. A target is confirmed at 120 mm. What will the sensor output?
What is the key advantage of a "teach-in" photoelectric sensor compared to one with a fixed sensitivity potentiometer?
A magnetostrictive linear position sensor (e.g. MTS Temposonics) reports position via a SSI (Synchronous Serial Interface). What is the main advantage over an LVDT for long-stroke (> 1 m) applications?
What is the NAMUR standard (IEC 60947-5-6) for proximity sensor outputs, and when is it used?
A radar level sensor transmits at 26 GHz into a vessel. The echo returns after 4.2 µs. What is the distance to the liquid surface?
You need to measure flow in a 200mm diameter pipe carrying conductive liquid (conductivity > 5 µS/cm). Which flow technology is best?