Timers and Counters 340

555 integrated circuit

A type of integrated circuit that is often used to regulate the timing functions of electronic timers.

air bellows

An apparatus consisting of a flexible, valved air chamber that is contracted and expanded by pumping action to force air through a nozzle. Air bellows are used to sound a pipe organ, increase draft to a fire, or operate a pneumatic timer.

analog timer

A timer that tracks physical quantities or changes using a varying frequency. Unlike digital signals, analog signals easily handle input that is highly variable in quality and quantity.

arithmetic counter

A type of counter that performs arithmetic operations such as addition, subtraction, multiplication, and division.

automatic overriding program

A program that counteracts the normal operation of a device or process.

axle

A rotating shaft attached to a wheel or gear.

batch counter

A counter that counts in series a collection of objects or data that is treated as a single entity.

bimetal strip timer

A type of thermal timer that uses a strip formed by joining two different metals with different expansion rates into one strip that bends when the strip is exposed to heat and temperature changes.

cam

A circular or cylindrical machine component that converts rotational movement into linear movement.

cam timer

A type of mechanical timer that uses cams arranged along a shaft to alternately press down and release switches that control different timing elements of a system.

clutch

A coupling found inside a motorized device that engages or disengages parts to drive a mechanism.

composite load

The collection of devices or systems that consume energy from the timing system’s primary energy source.

contactor

A device that uses a small control current to energize or de-energize a load.

control device

Any input device that controls the flow of current in a circuit. Control devices determine when loads are energized or de-energized.

control screw

A screw that is tightened or loosened to refine the performance of a device.

count range

The maximum value the counter can count and register. The count range of the counter is determined by the number of digits the counter is able to display.

count speed

The value indicating how fast a counter can count. Count speed is measured at counts per minute and varies depending on the type of counter.

counter

A device that counts, calculates, or keeps a record of the number of times something happens.

dashpot timer

A category of mechanical action timers that operate by displacing air or viscous fluid. Dashpot timers are the oldest type of industrial timer, and they are typically used for heavy-duty equipment.

delay timer

A timer that delays turning on a device until a preset time period has passed. A delay timer in a car automatically shuts off the headlights after the car has been turned off.

delayed make

An elapsed span of time before two electrodes connect to form a circuit.

dial

A flat disk containing numbers or markings around it that rotates to display a specific setting or an output value.

digital

Consisting of information that is input or output electronically as a series of pulses or signals either "on" or "off," often resulting in binary strings of 0s and 1s.

digital timer

A timer that operates electronically, providing input or output as a series of pulses in binary strings of 0s and 1s.

DIP switches

A Dual In-line Package Switch. DIP switches use binary settings, on-off / yes-no, to configure various options on a device.

down-count

Counting in a downward or decreasing direction. Counting 3, 2, 1, and so on is a down-count.

dual-bimetal-strip timer

A type of thermal timer that uses two bimetal strips. A bimetal strip joins two different metals with different expansion rates into one strip that bends when the strip is exposed to heat.

electromechanical counter

A category of counters that operate through a combination of electricity and mechanical motion. Electromechanical counters receive an electrical input signal and convert it to mechanical action to output a count, stop a count, or reset the counter to zero.

electromechanical timer

A category of timers that operate through a combination of electricity and mechanical motion. Electromechnical timers are gradually being replaced by solid state technology.

electronic counter

A category of counters that operate through electricity only. Electronic counters execute counting functions through digital signals and can handle fast counting rates.

electronic timer

A category of timers that operate through electricity only and have no moving mechanical parts.

event counter

A counter that counts how many times a specified condition occurs.

frequency counter

A counter that counts the number of times something happens within a specific time or count limit. In essence, a frequency counter combines the functions of a timer and counter.

gear

A circular toothed component that engages, rotates, and transmits power to another circular toothed component when rotated.

gear train

A set of gears arranged to transfer mechanical energy from one part of a mechanical system to another.

hydraulic timer

A type of timer that creates a time delay by controlling the rate at which liquid passes into or out of a container.

hysteresis

The delay between the action and reaction of a measuring instrument. Hysteresis also refers to the tendency of a component's position to be dependent on the previous position of the component when reacting to a physical stimulus.

idle state

The state in which current is flowing, but a device is not energized or in motion.

integrated circuit

A miniaturized electrical network used to transmit electric power. A microchip is an example of an integrated circuit.

interval timer

A timer that begins the timing period when the control coil is turned on and starts an operational cycle. The control coil remains on and the contacts turn on for a time, then off for a time. This cyclical event is the interval.

LED display

A luminous panel on which digital readouts are displayed.

load control element

The part of a timing system that controls the load when it receives a signal from the triggering element and switches the load.

manual override

A procedure in which an automatic system is put under manual control.

mechanical counter

A category of counters not powered by electricity, but by mechanical means such as pushing a button or turning a knob.

mechanical timer

A category of timers not powered by electricity, but by mechanical means using air bellows, pistons, or plungers.

mercury

A metallic element that is liquid at room temperature. Mercury is used in mercury displacement timers and acts as the contactor in the device.

mercury displacement timer

A timer that operates by displacing a pool of mercury in a container. Mercury displacement timers are used in environments that may get very hot, or that require the timer to be completely sealed.

motor-driven cycle timer

A motor-operated timer that cycles on and off continuously, or goes through one cycle only.

motor-driven delay timer

A motor-operated timer that creates a delay after the coil is energized.

motor-driven interval timer

A motor-operated timer that begins the timing period when the control coil is turned on and starts an operational cycle. The control coil remains on and the contacts turn on for a time, then off for a time. This cyclical event is the interval.

motor-driven reset cycle timer

A motor-operated timer that returns to its original starting position after a preset time interval has passed.

motor-driven timer

A timer that is operated by a motor. Motor-driven timers are also referred to as cam timers.

multivibrator

An electronic circuit used to control signal pulses.

NC

Normally closed. An NC electrical contact regularly allows electricity to flow until it is signaled to open.

needle valve orifice

The opening to a valve used to provide very fine adjustment. Needle valves require many turns to open them completely.

NO

Normally open. An NO electrical contact does not allow electricity to flow until it is signaled to close.

off-delay timer

A delay timer that immediately closes contacts when the control coil is energized, then waits for a predetermined amount of time to open them after power is removed from the coil.

on-delay timer

A delay timer that waits for a predetermined amount of time before closing a set of contacts and energizing a load.

operating lifetime

The length of time that a device will work before it becomes unreliable or stops functioning.

oscillator

An electronic device used to generate a vibrating signal at a constant rate.

PLC

Programmable Logic Controller. A processor driven device that uses logic based software to provide electrical control to machines.

pneumatic timer

A timer that creates a time delay by controlling the rate at which air passes into or out of an air bellows.

predetermining counter

A counter set in advance to stop or produce output once a specific count has been reached. A predetermining counter is also called a preset counter.

preset counter

A counter set in advance to stop or produce output once a specific count has been reached. A preset counter is also called a predetermining counter.

pushbutton counter

A type of mechanical counter used for manual counting. The operator actuates a pushbutton and records one count for each actuation.

pushbutton switch

A manual control device that opens or closes a circuit when pressed. Pushbuttons can be normally open or normally closed.

recycle timer

A timer that performs continuously until it is stopped.

relay

A device that controls one electrical circuit by opening and closing contacts in another circuit.

repeat cycle timer

A timer that performs continuously until it is stopped.

reset timer

A type of recycle timer that uses a clutch mechanism to actuate a motor-driven gear assembly and start a cycle.

resolution

The smallest value that can be counted. This value can be as small as 1/1000th.

revolution counter

A counter that records one count for each revolution of the shaft. Revolution counters are used in odometers to keep track of the miles that tires run by counting axle revolutions.

rotary counter

A counter that records a specified number of counts per rotation.

rotary ratchet counter

A type of stroke counter. Stroke counters record one count for each stroke.

safety interlock

A safety device that disables or prevents a machine startup if a guard or door remains open.

single revolution cycle

One turn of a mechanical device.

slow break

Allowing for a delay before the connection is broken.

solenoid

A type of output device coil that converts electrical energy into mechanical energy via magnetic fields to exert a force, typically in a linear direction. Soleniods can be used to activate switches and valves.

solid state

Functioning by means of electronic components without the use of moving parts.

solid state timer

A timer that functions by means of electronic components without the use of moving parts.

stroke counter

A counter that records one count for each stroke. A stroke is a reciprocating back and forth motion.

thermal expansion timer

A timer that operates by heating an upright piece of metal, causing it to expand and close a set of contacts.

thermal timer

A type of analog timer that uses heat generated from an electric current to bend a bimetal strip, which closes a set of normally open contacts. The time it takes to heat the bimetal strip produces the timing delay.

thumbwheel

A rotary device that allows an operator to input numerical information into a counter.

timer

A control device that automatically starts or stops machines and other devices when a preset time period has been exceeded.

timing element

The mechanism in a timing system that produces the time delay.

timing system

An electronic system that uses a timer to energize or de-energize a load.

totalizing counter

A counter that sums up the total times something has occurred since the last time the counter was used. Most totalizing counters are non-resettable, and will simply roll over to zero once they have exceeded their count range.

triggering element

The part of an electronic timer that detects changes in the timing element and processes the signal for the load control element. Usually this involves amplifying the signal enough to trigger the load control switch.

up-count

Counting in an upward or increasing direction. Counting 1, 2, 3, and so on is an up-count.

viscosity

A fluid's resistance to flow. Viscosity is used to describe friction of fluid.