(Machine Safety) Short for Emergency Stop. The actuation of an emergency switch resulting in the arrest of dangerous machine motion.

(Machine Safety) A device that, when actuated, arrests dangerous motion. The device typically is a button, rope, cable pull, or trip/foot bar used to generate an emergency stop.

(Vision Sensing) A change in pixel values exceeding some threshold between two adjacent regions of relatively uniform values. Edges correspond to changes in brightness corresponding to a discontinuity in surface orientation, reflectance, or illumination.

(Machine Safety) Abbreviation for External Device Monitoring, a means by which a safety device monitors the state of external devices that may be controlled by the safety device.

(Machine Safety) The maximum angle of deviation from the optical alignment of the emitter and the receiver within which the safety light screen continues in normal operation. Also known as Angle of divergence/acceptance, or Field-of-view.

The "working" part of a photoelectric beam. Not to be confused with the actual radiation pattern of the emitter, or with the field of view of the receiver.

(Machine Safety) See Active Opto-electronic Protective Device

A continuum encompassing all the wavelengths of electromagnetic radiation.

Any device using electrical energy to produce mechanical movements.

Conventional switching relays consisting of "hard" contacts (metal-to-metal), switched to opened or closed position by applying voltage to an electromagnetic coil.

(Machine Safety) A control function initiated by a single human action to arrest dangerous machine motion, or otherwise avert or reduce existing hazards to persons, damage to machinery or to work in progress.

Abbreviation for electromagnetic interference. Electrical "noise" which may interfere with proper operation of sensors, programmable logic controllers, counters, data recorders, and other sensitive electronic equipment. Common sources of EMI include high-frequency light fixtures, controls, motors, generators, contactors and other inductive loads.

Emissivity is a measurement of the thermal signature and characteristics of different materials and surfaces. Anything in nature with a temperature above absolute zero emits energy. Emissivity measurement is represented as a ratio of energy emitted by an object at a given temperature to energy emitted by a blackbody at the same temperature. A blackbody is a perfect radiator with an emissivity of 1. Typical objects have an emissivity of .5 to .98. On the opposite end of the spectrum, a mirror has an emissivity of 0.

1. The sensor containing the source of sensing energy in opposed-mode sensing.
2. The emitting device within any sensor (e.g. LED, laser diode, ultrasonic transducer, etc.).

(Machine Safety) The light-emitting component of a safety light screen system, consisting of a row of synchronized modulated LEDs. The emitter, together with the receiver (placed opposite), creates a "screen of light" called the defined area.

(Machine Safety) Abbreviation for European Normale. A prefix given to a European standard, adopted by CEN/CENELEC, which must be implemented as a national standard within the EU and participating countries. While national deviations are allowed, any conflicting national standard must be withdrawn.

The physical conditions into which a sensor is placed.

A thermosetting resin characterized by toughness, strong adhesion, and low shrinkage.

Access method for computer network (Local Area Networks) communications, as defined within the IEEE 802 standard.

European Telecommunications Standards Institute. Non-profit organization dedicated to standardizing telecommunications in Europe.

A configuration allowing a light screen system to ignore stationary objects (such as brackets or fixtures) that interrupt a specific number of light beams. If any other light beams other than the specified ones are interrupted during RUN mode, a Lockout condition will result.

Excess gain is a photoelectric sensor specification. It is a measurement of the amount of light falling on the receiver of a sensing system over and above the minimum amount of light required to just operate the sensor’s amplifier.

Excess gain is plotted versus sensing distance. In equation form: EXCESS GAIN = Light energy falling on the receiver divided by the amplifier threshold. Excess gain values are used in the sensor selection process to predict the reliability of a photoelectric sensor in a known sensing environment.

Spacers between the lens and the camera that allow the lens to focus at closer working distances.

(Machine Safety) A means by which a safety device (such as a safety light screen) actively monitors the state (or status) of external devices that may be controlled by the safety device. A lockout of the safety device will result if an unsafe state is detected in the external device. External device(s) may include, but are not limited to: MPCEs, captive contact relays/contactors, and safety modules.