Industrial automation glossary
60 terms used every day in control panels, PLCs, pneumatics and process control, each with its Spanish name and a link to the topic or simulator where it is explained in depth.
# A B C D E F G H I L M N O P R S T U V
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- 4–20 mA signal ES: Señal 4–20 mA
- Industrial analog signal: 4 mA is the bottom of the scale and 20 mA the top. Below 4 mA there is a fault, such as a broken wire. More on this →
- 5/2 solenoid valve ES: Electroválvula 5/2
- Pneumatic valve with five ports and two positions, operated by a coil. It is the usual valve for double-acting cylinders. More on this →
A
- Analog scaling ES: Escalado analógico
- Converting the raw value of an analog input into real units. In Siemens, 0–27648 corresponds to the signal range (for example 4–20 mA). More on this →
B
- Breaking capacity ES: Poder de corte
- The highest short-circuit current a protective device can interrupt without being destroyed, for example 6 kA or 10 kA. More on this →
C
- Capacitive sensor ES: Sensor capacitivo
- Proximity sensor that detects almost any material, even liquids through a plastic tank. More on this →
- Circuit breaker (MCB) ES: Magnetotérmico
- Switch that protects cables against overload (thermal part) and short circuit (magnetic part). It is chosen by rating, curve and breaking capacity. More on this →
- Cobot ES: Cobot
- Collaborative robot, designed to work near people by limiting its force and speed. It does not remove the need for a risk assessment. More on this →
- Coil (A1-A2) ES: Bobina (A1-A2)
- Electromagnet of a contactor or relay. When A1-A2 is energised it closes its contacts. Always check its voltage: 24 V DC, 230 V AC… More on this →
- Commissioning ES: Puesta en marcha
- The ordered tests done before handing over a machine: dead checks, power section by section, inputs, outputs, safety functions and cycle. More on this →
- Contactor ES: Contactor
- Switch operated by a coil, which lets a small signal (a PLC output) switch a large load, such as a motor. More on this →
- Counter (CTU, CTD) ES: Contador (CTU, CTD)
- PLC block that counts rising edges of an input: CTU counts up to PV and CTD counts down to 0. More on this →
D
- Dead time ES: Tiempo muerto
- How long the measurement takes to start moving after a controller's output changes. The longer it is, the harder fast control becomes. More on this →
- Double coil ES: Doble bobina
- Programming mistake: writing the same output in two places in the program. The last write of the scan wins and the first one is useless. More on this →
- Double-acting cylinder ES: Cilindro de doble efecto
- Pneumatic cylinder that extends and retracts on air, with a chamber on each side of the piston. It is driven by a 5/2 valve. More on this →
E
- Edge (rising or falling) ES: Flanco
- The moment a signal changes: from 0 to 1 (rising edge) or from 1 to 0 (falling edge). In the PLC it lasts a single scan. More on this →
- Red button on a yellow background that stops the machine safely. It latches and has to be reset by hand. More on this →
F
- Five safety rules ES: Cinco reglas de oro
- Disconnect, lock out, verify absence of voltage, earth and short-circuit, and protect and mark. Always in that order, to work dead. More on this →
- Flow control valve ES: Regulador de caudal
- Adjustable restriction with a check valve that sets a cylinder's speed. The exhaust air is normally the one restricted (meter-out). More on this →
G
- GRAFCET (sequential function chart) ES: GRAFCET
- Standard way of drawing a sequence: steps (what is done) and transitions (the condition to move on to the next one). More on this →
H
- HMI (operator panel) ES: HMI (pantalla de operador)
- Screen from which the operator sees the machine's state, changes parameters and receives alarms. More on this →
I
- Inductive sensor ES: Sensor inductivo
- Proximity sensor that only detects metal, at a few millimetres. Very robust and the most common on machines. More on this →
- Integral windup ES: Windup (saturación de la integral)
- A PID's integral keeps growing with the output at its limit, and then the process overshoots badly. Anti-windup prevents it. More on this →
- Interface relay ES: Relé de interfaz
- Relay between the PLC output and the load: it protects the card and lets you switch other voltages. More on this →
- Interlock ES: Enclavamiento
- Condition that prevents two things happening at once, such as the forward and reverse contactors closing together. It can be electrical, mechanical or in the program. More on this →
L
- Ladder logic (LAD) ES: KOP (esquema de contactos)
- PLC programming language drawn like an electrical diagram, with contacts and coils. The most used in maintenance. More on this →
- Limit switch ES: Final de carrera
- Mechanical switch operated by a lever or plunger when a part reaches a position. More on this →
- Lockout/tagout (LOTO) ES: Consignación
- Locking a disconnected device with a personal padlock and a tag with name, date and reason, so nobody can switch it back on during the work. More on this →
M
- Modbus ES: Modbus
- Simple, widely used industrial protocol, over RS-485 (RTU) or Ethernet (TCP). Common with drives and meters. More on this →
- Monostable and bistable valve ES: Monoestable y biestable
- A monostable valve returns to rest on a spring when the signal is removed; a bistable valve has two coils and stays in the last position. More on this →
- Motor protection circuit breaker (MPCB) ES: Guardamotor
- Device that protects a motor against short circuits and, with an adjustable thermal part, against overloads. It is set to the nameplate current. More on this →
- Multimeter ES: Multímetro
- Instrument for measuring voltage, current, resistance and continuity. What matters is choosing the right function, socket and measurement category. More on this →
N
- Normally closed contact (NC) ES: Contacto normalmente cerrado (NC)
- Contact that is closed at rest and opens when operated. On auxiliary contacts, numbers ending in 1-2 (21-22, 61-62). Stop buttons are wired this way. More on this →
- Normally open contact (NO) ES: Contacto normalmente abierto (NA)
- Contact that is open at rest and closes when operated. On auxiliary contacts, numbers ending in 3-4 (13-14, 23-24). More on this →
O
- OEE (overall equipment effectiveness) ES: OEE
- Measure of how well a machine is used: availability × performance × quality. 85 % is considered world class. More on this →
- Off-delay timer (TOF) ES: Temporizador TOF
- Q turns on at once with IN and, when IN is removed, stays on for the time PT. Used, for example, to keep a fan running for a while. More on this →
- On-delay timer (TON) ES: Temporizador TON
- Q turns on when IN has been at 1 for the time PT. If IN is removed earlier, it resets. The most used: delays and filters. More on this →
- Overload ES: Sobrecarga
- A little more current than intended for some time, for example a motor under strain. It heats the cable slowly. More on this →
- Overload relay ES: Relé térmico
- Motor overload protection. Its 95-96 contact opens the control circuit when it trips, and 97-98 signals it. More on this →
P
- Payback period ES: Plazo de recuperación
- How long an investment, such as an automation project, takes to pay for itself with what it saves. More on this →
- Phase and line voltage ES: Tensión de fase y de línea
- In a three-phase supply, the voltage between two phases (line) is √3 times the phase-to-neutral voltage: 400 V ≈ √3 × 230 V. More on this →
- Photoelectric sensor ES: Sensor fotoeléctrico
- Sensor that uses a light beam: through-beam (separate emitter and receiver), retro-reflective (with a reflector) or diffuse (light returned by the object). More on this →
- PID controller ES: PID
- Controller that works out its output from the error with three actions: proportional, integral and derivative. Most industrial loops are PI. More on this →
- PNP and NPN (sourcing and sinking) ES: PNP y NPN
- Output type of a 3-wire sensor: PNP gives +24 V when it detects and NPN connects the output to 0 V. The PLC card has to match. More on this →
- Power factor (cos φ) ES: Cos φ (factor de potencia)
- What share of the apparent power is useful. A low power factor means more current for the same work, and it is corrected with capacitors. More on this →
- Process image ES: Imagen de proceso
- Copy of the inputs and outputs in the PLC's memory. The program works with that copy, which is updated at the start and end of each scan. More on this →
- Process variable (PV) ES: Medida (PV)
- The actual value the sensor measures in a control loop, such as the oven temperature. The controller compares it with the setpoint. More on this →
- Profinet ES: Profinet
- Industrial Ethernet network widely used with Siemens PLCs. Each device has a device name as well as its IP address. More on this →
- Programmable logic controller (PLC) ES: Autómata programable (PLC)
- Industrial computer that reads inputs (buttons, sensors), runs a program in cycles and writes outputs (contactors, valves). It is the brain of almost every machine. More on this →
- Pulse timer (TP) ES: Temporizador TP
- On an edge of IN, Q gives a pulse lasting PT, whatever IN does afterwards. More on this →
R
- Residual current device (RCD) ES: Diferencial
- Device that compares outgoing and returning current and trips if some is missing (earth leakage). The 30 mA type protects people. In North America, a GFCI. More on this →
S
- Scan cycle ES: Ciclo de scan
- What the PLC does over and over: read all the inputs, run the program from top to bottom and write the outputs. It takes a few milliseconds. More on this →
- Seal-in (holding contact) ES: Autorretención
- Contact of the contactor itself (13-14) in parallel with the start button, which keeps the coil energised when the button is released. In a PLC, the output in parallel with start. More on this →
- Setpoint (SP) ES: Consigna (SP)
- The value a control loop is trying to reach: 200 °C, 3 bar, 60 % level. The controller compares the measurement with it. More on this →
- Short circuit ES: Cortocircuito
- Two points at different voltages joined with almost no resistance. The current rises to hundreds or thousands of amps and must be interrupted in milliseconds. More on this →
- Slip ES: Deslizamiento
- Difference between the speed of the rotating field and the rotor of an induction motor. A 1500 rpm synchronous motor turns at, say, 1450. More on this →
- Star-delta (wye-delta) starter ES: Estrella-triángulo
- Starter that connects the motor in star and then changes to delta. Starting current and torque drop to a third. More on this →
- Structured Text (ST, SCL) ES: SCL (texto estructurado)
- PLC language similar to a computer programming language, with IF, CASE and loops. Handy for calculations and complex logic. More on this →
T
- True RMS ES: True RMS
- Meter that measures the RMS value correctly even when the waveform is not sinusoidal, such as at a drive output. More on this →
U
- Utilization category AC-3 ES: Categoría de empleo AC-3
- Contactor duty class for starting and stopping squirrel-cage motors. A contactor is chosen by its AC-3 current, not its AC-1 rating. More on this →
V
- Variable frequency drive (VFD) ES: Variador de frecuencia
- Device that changes the frequency and voltage fed to a motor to control its speed. Rectifier, DC bus and inverter. More on this →