Automation and Control Guides Page 7: 198 technical guides for choosing Automation and Control products: selection criteria, standards, common mistakes and frequently asked questions.
What Is an On-Off Thermostat? Types and Selection Criteria — An on-off thermostat is a digital temperature controller that compares the probe reading with the setpoint and switches a heater or cooler fully on or off within a hysteresis band. What Is a Diffuse Reflective Cylindrical Photoelectric Sensor? Types and Selection Criteria — A diffuse reflective cylindrical photoelectric sensor has its emitter and receiver in one M12 or M18 threaded housing and detects objects by the light they reflect. What Is a PLC Relay (PCB Relay)? Types and Selection Criteria — A PLC relay is a slim interface relay whose coil is driven by a PLC output and whose contact switches the load, isolating the PLC output from the load circuit. What Is a Multi-Function Timer Relay? Types and Selection Criteria — A multi-function timer relay is a timer relay with selectable functions that offers several timing modes in one device, such as on-delay, off-delay, interval and flasher. What Is a Braking Resistor? Types and Selection Criteria — A braking resistor is a power resistor that converts into heat the energy a motor returns to the drive's DC bus when it is slowed down by a frequency inverter. What Is a Mushroom Head Push Button? Types and Selection Criteria — A mushroom head push button is a spring-return or latching panel button with a wide head, usually Ø40 mm, that the operator can press with the palm without looking. What Is a Digital Output Module? Types and Selection Criteria — A digital output module is an expansion module that passes the PLC CPU's on/off commands to loads such as contactors, valves and lamps through relay, transistor or triac outputs. What Is a Short-Body Cylindrical Photoelectric Sensor? Types and Selection Criteria — A short-body cylindrical photoelectric sensor is a photoelectric sensor with a shortened threaded M18 housing for tight mounting points with little space behind the sensor. What Is an M30 DC 3/4-Wire Inductive Sensor? Types and Selection Criteria — An M30 DC 3/4-wire inductive sensor is a DC proximity sensor with an M30×1.5 threaded housing that detects metal without contact from 10–30 mm. What Is a Panel PC? Choosing Processor, Screen and Operating System — A panel PC is an industrial computer that combines a touchscreen and a computer in one housing and is flush-mounted into a panel door or machine housing. What Is a Slim Relay? Types and Selection Criteria — A slim relay is a narrow coupling relay mounted side by side on a DIN rail that acts as an interface between a PLC output and the field circuit. What Is a Rotary Limit Switch? Types and Selection Criteria — A rotary limit switch counts the revolutions of a multi-turn shaft, such as a crane drum, through gear reduction and changes its contacts at set points. What Is a Diffuse Reflective Rectangular Photoelectric Sensor? Types and Selection Criteria — A diffuse reflective rectangular photoelectric sensor has its emitter and receiver in one box-shaped housing and detects objects by the light they reflect, mounted from one side with no reflector. What Is a Digital Voltmeter? Types and Selection Criteria — A digital voltmeter is a measuring device that shows AC or DC voltage in volts on a numeric display and fits into a panel door or onto a DIN rail. What Is a Sensor Connector? M8 and M12 Types and Selection Criteria — A sensor connector is the plug that joins an inductive, capacitive or photoelectric sensor to its cable through a threaded M8 or M12 socket, so the sensor can be swapped without rewiring. What Is an AC Two-Wire Metal Photoelectric Sensor? Types and Selection Criteria — An AC two-wire metal photoelectric sensor is a cylindrical photoelectric sensor with a threaded metal housing that is wired in series with the load and switches it directly at AC voltage. What Is a DC Metal-Body Cylindrical Photoelectric Sensor? Types and Selection Criteria — A DC metal-body cylindrical photoelectric sensor has a threaded M18 or M30 metal housing that withstands impact and vibration, a DC supply and an NPN or PNP output. What Is a Plastic-Body Cylindrical Photoelectric Sensor? Types and Selection Criteria — A plastic-body cylindrical photoelectric sensor is a DC-supplied sensor in an M18 or M30 threaded plastic housing that detects objects contactlessly with a light beam and signals a PLC or relay. What Is an AC 2-Wire Inductive Sensor? Types and Selection Criteria — An AC 2-wire inductive sensor is a two-terminal proximity sensor that detects metal without contact and switches an AC load directly, wired in series with it. What Are Counters and Tachometers? Types and Selection Criteria — A counter is a panel-mount device that counts and displays pulses from a sensor or contact; a tachometer calculates and displays speed from the pulse frequency. What Is a Digital Ammeter? Types and Selection Criteria — A digital ammeter is a panel or DIN rail meter that measures line current through a current transformer, direct connection or DC shunt and shows it on a numeric display. What Is a Digital Panel Multimeter? Types and Selection Criteria — A digital panel multimeter is a panel door or DIN rail device that shows line voltage, current, frequency and, depending on the model, power factor on one display. What Is a Through-Beam Rectangular Photoelectric Sensor? Types and Selection Criteria — A through-beam rectangular photoelectric sensor has its emitter and receiver in two separate box-shaped housings and switches its output when an object breaks the beam between them. Push Button and Pilot Light Accessories Selection Guide — For LED blocks, voltages such as 12-30 V AC/DC and 100-230 V AC are offered under separate codes; match your control voltage with the value in the product name.