Timers and Counters 340
This class describes the functions and applications of various mechanical, electromechanical, and electronic timers and counters. Includes an Interactive Lab.
Number of Lessons 18
- Timers and Counters
- Parts of a Timing System
- Timer Applications
- Interval and Delay Timer Functions
- Recycle and Reset Timer Functions
- Timer Classifications
- Thermal Timers
- Motor-Driven Delay and Interval Timers
- Motor-Driven Cycle and Recycle Timers
- Mechanical Action Timers
- Electronic and Solid State Timers
- Counter Applications
- Counter Functions
- Mechanical Counter Classifications
- Electromechanical Counters
- Electronic Counters
- Describe timers and counters.
- Describe the parts of a timing system.
- Describe timer applications.
- Describe delay and interval timer functions.
- Describe recycle and reset timer functions.
- List the different types of timers.
- Describe thermal timers.
- Describe delay and interval motor-driven timers.
- Describe cycle and recycle motor-driven timers.
- Describe mechanical action timers.
- Describe electronic and solid state timers.
- Describe counters applications.
- Describe counter functions.
- List the different types of mechanical counters.
- Describe electromechanical counters.
- Describe electronic counters.
555 integrated circuit
A type of integrated circuit that is often used to regulate the timing functions of electronic timers.
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.
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.
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.
A rotating shaft attached to a wheel or gear.
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.
A circular or cylindrical machine component that converts rotational movement into linear movement.
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.
A coupling found inside a motorized device that engages or disengages parts to drive a mechanism.
The collection of devices or systems that consume energy from the timing system’s primary energy source.
A device that uses a small control current to energize or de-energize a load.
Any input device that controls the flow of current in a circuit. Control devices determine when loads are energized or de-energized.
A screw that is tightened or loosened to refine the performance of a device.
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.
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.
A device that counts, calculates, or keeps a record of the number of times something happens.
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.
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.
An elapsed span of time before two electrodes connect to form a circuit.
A flat disk containing numbers or markings around it that rotates to display a specific setting or an output value.
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.
A timer that operates electronically, providing input or output as a series of pulses in binary strings of 0s and 1s.
A Dual In-line Package Switch. DIP switches use binary settings, on-off / yes-no, to configure various options on a device.
Counting in a downward or decreasing direction. Counting 3, 2, 1, and so on is a down-count.
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.
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.
A category of timers that operate through a combination of electricity and mechanical motion. Electromechnical timers are gradually being replaced by solid state technology.
A category of counters that operate through electricity only. Electronic counters execute counting functions through digital signals and can handle fast counting rates.
A category of timers that operate through electricity only and have no moving mechanical parts.
A counter that counts how many times a specified condition occurs.
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.
A circular toothed component that engages, rotates, and transmits power to another circular toothed component when rotated.
A set of gears arranged to transfer mechanical energy from one part of a mechanical system to another.
A type of timer that creates a time delay by controlling the rate at which liquid passes into or out of a container.
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.
The state in which current is flowing, but a device is not energized or in motion.
A miniaturized electrical network used to transmit electric power. A microchip is an example of an integrated circuit.
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.
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.
A procedure in which an automatic system is put under manual control.
A category of counters not powered by electricity, but by mechanical means such as pushing a button or turning a knob.
A category of timers not powered by electricity, but by mechanical means using air bellows, pistons, or plungers.
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.
A timer that is operated by a motor. Motor-driven timers are also referred to as cam timers.
An electronic circuit used to control signal pulses.
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.
Normally open. An NO electrical contact does not allow electricity to flow until it is signaled to close.
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.
A delay timer that waits for a predetermined amount of time before closing a set of contacts and energizing a load.
The length of time that a device will work before it becomes unreliable or stops functioning.
An electronic device used to generate a vibrating signal at a constant rate.
Programmable Logic Controller. A processor driven device that uses logic based software to provide electrical control to machines.
A timer that creates a time delay by controlling the rate at which air passes into or out of an air bellows.
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.
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.
A type of mechanical counter used for manual counting. The operator actuates a pushbutton and records one count for each actuation.
A manual control device that opens or closes a circuit when pressed. Pushbuttons can be normally open or normally closed.
A timer that performs continuously until it is stopped.
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.
A type of recycle timer that uses a clutch mechanism to actuate a motor-driven gear assembly and start a cycle.
The smallest value that can be counted. This value can be as small as 1/1000th.
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.
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.
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.
Allowing for a delay before the connection is broken.
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.
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.
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.
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.
A rotary device that allows an operator to input numerical information into a counter.
A control device that automatically starts or stops machines and other devices when a preset time period has been exceeded.
The mechanism in a timing system that produces the time delay.
An electronic system that uses a timer to energize or de-energize a load.
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.
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.
Counting in an upward or increasing direction. Counting 1, 2, 3, and so on is an up-count.
A fluid's resistance to flow. Viscosity is used to describe friction of fluid.