Reddington

Glossary

A-B Input: The B input pulses are subtracted from the A input pulses.; This type of input is used on counters & indicators.
A+B Input: The A and B input pulses are added together. This type input is used on counters and position indicators.
AC: Alternating current; an electric current that reverses its direction at recurring intervals.
Accuracy: The closeness of an indication or reading of a measurement device to the actual value of the quantity being measured. Usually expressed as a ± percent of full scale output or reading,
Add/Subtract: The ability to count up and down.
Ammeter: An instrument used to measure current.
Analog: A signal that varies continuously in amplitude without interruption.
Analog Output: A circuit whose output is a reproduction of its input..
Automatic Reset: A reset that is based on a pre-programmed event. Used in counters or timers.
Baud Rate: The rate at which each bit is transferred to and from a device.
Bidirectional: The counter or encoder can count in both directions.
Bit: This is the name for a binary digit.
Byte: A sequence of adjacent binary digits operated on as a single unit. A byte is eight bits in length.
Capacitor: An assembly of one or more pairs of conductors separated by insulators used to store an electrical charge. The capacitance of is measured in FARADS or parts thereof.
CE: (Conformite Europeeene mark) A symbol (CE) applied to finished products and machinery indicating it meets all applicable European Directives. For electrical and electronic “finished products”, such as electronic and electromechanical counters, hour meters, these include the Low Voltage Directive and, where relevant, the Electromagnetic Compatibility (EMC) Directive.
Control point: The set point at which a system is to be maintained.
CSA: (Canadian Standards Association) An independent Canadian testing and standards-making org. similar to Underwriters Laboratories (UL) in the USA. “CSA -certified “ products meet relevant CSA electrical and safety standards.
Current sinking /Open collector: In the “off” state the transistor can be viewed as an open switch. When energized it turns “ON”, connecting the output to the ground return lead. The transistor is usually NPN.
Current sourcing/Open collector: In the “off” state the transistor can be viewed as an open switch. When energized it turns “ON”, connecting the output to the voltage supply lead. The transistor is usually PNP.
DC: Direct current: An electric current flowing in one direction only and substantially constant in value.
Die: A single piece of silicon onto which a semiconductor circuit has been fabricated.(Plural= Dice)
Digit: A measurement of the display span of a panel meter. By convention, a full digit can assume any value from 0 through 9, a 1/2 digit will display a 1 and overload at 2. For example, the full scale value of a 3 1/2 digit display is 1999.
DIN: A Deutsche Industrial Norme standard. Some; RCI products utilize these dimensional standards.
Direct drive: Refers to the gear ratio in a mechanical counter one revolution of the input shaft equals 10 counts.
Drift: Refers to the gear ratio in a mechanical counter one revolution of the input shaft equals 10 counts.
EMF: Electromotive force. A rise in (electrical) potential energy. The principle unit is the volt.
EMI: Electromagnetic interference.
Encoder: An electromechanical device that translates mechanical motion into electrical pulses.
FRAM: Nonvolatile memory. Uses the ferroelectric effect for a storage mechanism.
Hertz: (Hz) Units in which the frequency is expressed. Synonymous with cycles per second.
Hysteresis: In an ON-OFF controller it defines the difference between the two switching points. It refers to the difference between the value at which the alarm switches on and the value at which the alarm switches off again.
Incremental encoder: A device that provides a series of periodic signals due to mechanical motion. The number of successive cycles corresponds to the resolvable mechanical increments of motion.
Impedance: The total opposition to electrical flow (resistive plus reactive).
Input impedance: The resistance of a panel meter as seen from the source. In the case of a voltmeter, this resistance has to be taken into account when the source impedance is high; in the case of an ammeter, when the impedance is low.
Joule: The basic unit of thermal energy.
LCD: (Liquid Crystal Display) A liquid crystal display is made of two glass plates, each with a transparent conductive coating, which sandwich the crystal material. When a voltage is applied molecules in the liquid crystal align themselves with the field generated preventing light from passing, creating a display segment. The pattern on the display forms the required picture or numeral.
LED: (Light Emitting Diode) A diode which emits light of a particular wavelength when a current is passed through it.
LSI: ( Large Scale Integration) Used to refer to integrated circuits which today have from thousands to millions of components on one silicon chip.
Load: The electrical demand of a process expressed as power (watts), current (amps), or resistance (ohms).
Maximum operating temperature: The maximum temperature at which an instrument can be operated and still be within operating specifications.
Micro: A prefix meaning one millionth.
Milli: A prefix meaning one thousandth.
Multiplication: Any technique used to obtain an output resolution different from the line count.
Nano: A prefix meaning one thousand-millionth.
Noise: An unwanted electrical interference on the signal wires.
OHM: The unit of electrical resistance. A constant voltage of one volt across a resistance of one OHM will produce a current in it of one ampere. OHMS LAW V=IR
Ohmmeter: An instrument used to measure resistance.
Optical Isolator: Sometimes referred to as an optocoupler. A device that isolates two stages of a circuit; e.g.., input and output from each other so that interference in one will not effect the other.
Optical Isolation: A method of reducing noise interference between two circuits using optical isolators.
Predetermining: The counter can provide an “output” signal at a predetermined count or time.
Prescaler: Used to convert a pulse input signal to the desired units of indication.
Quadrature Signals: A dual output encoder used for bidirectional motion control. One channel leads the other by 90 degrees.
RAM: ( Random Access Memory) A memory device which may be accessed at random and which may be written to (altered) or read at any time.
Range: The values specified by upper and lower limits.
Rate: Velocity or distance/unit time; can be rotational distance.
Relays/Electromechanical: Relays offer one or more “hard” contacts (metal-to metal) and are switched to the open or closed position by applying voltage to an electromagnetic coil.
Resistance: The resistance to the flow of electric current measured in ohms. For a conductor, a resistance is a function of diameter, resistivity (an intrinsic) property of the material and length.
Resistor: A device used primarily for its resistance, which is measured in OHMS. Its primary use is to limit the flow of electrons through a circuit.
Resolution: The number of increments on an encoder disc. Also, the smallest possible value that an instrument can measure.
Revolution drive: Refers to the gear ratio in a mechanical counter. One revolution of the input shaft equals 1 count.
ROM: (Ready Only Memory) A device is programmed with information which should not be lost and which only needs to be read by a computer. Once programmed it cannot be reprogrammed.
RS 485/422/232: Standards established by the EIA for serial data transmission between two devices.
RTD: Resistance temperature detector. The resistance changes as a function of temperature.
Scaling: For direct readout in engineering units, scaling is the capability of the product to associate any desired value to the electrical input range.
Silicon: The basic element used in the manufacturer of most semiconductor devices.
Solid-State Relays: Use switching elements such as transistors for DC loads and SCR’s or FET’s for AC loads.
Stroke Counter: Refers to the input shaft of a mechanical counter. The counter will count when the lever is moved through an arc.
Top coming: The input shaft rotates towards you, when viewing; the counter from the front.
Top going: The input shaft rotates away from you, when viewing; the counter from the front.
Totalizer: A type of counter with no outputs, which is used for accumulating the number of input pulses.
Transistor: From “transfer resistor”, it is a semiconductor device with three electrodes that act as either an amplifier or switch.
Transducer: A device (or medium) that converts energy from one form to another. The term is generally applied to devices that take physical phenomena (pressure, temperature, humidity, flow, etc.) and convert them to electrical signal. Sometimes referred to as “sensor”.
UL: Underwriters Laboratories, Inc. An independent laboratory that establishes safety standards for commercial and industrial products.
Unidirectional: The counter or encoder can only count in one direction.
Volt: The (electrical) potential difference between two points in a circuit. The fundamental unit is derived as work per unit charge- (V=W/Q). One volt is the potential difference required to move one coulomb of charge between two points in a circuit using one joule of energy.
X2,X4 Logic: A type of logic that multiplies the signal by a factor of 2 or 4 respectively.