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Aircraft Indicators
Backlit Inclinometers
Ball Banking
Bubble Levels
Boom Angle
Slip Indicators
Tilt Switches


This page contains common terms and phrases relevant to the inclinometer industry.

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 A/D Converter: A device that changes an analog signal (such as voltage) into a digital signal (discrete data values).
ACCELEROMETER (ac·cel·er·om·e·ter) n. an instrument for measuring acceleration or for detecting and measuring vibrations; an instrument for measuring the acceleration of (for example) aircraft or rockets.
accuracy: (in relation to gravity based inclinometers) - a sensor's true or absolute accuracy depends on the expected temperature range of the installation. It is a combination of initial sets of sensor zero offset and sensitivity, sensor linearity, hysteresis, repeatability, and the temperature drifts of zero and sensitivity. Typically in room ambient conditions the accuracy is limited to the sensor linearity specification.
Ampere: The unit of measurement of current.
AMPHENOL CONNECTOR: These are manufactured using a threaded coupling, which prevents unlocking, and an internal strain relief mechanism, which provides a safety net from cable strain. Made to withstand heavy industrial use and harsh environments, these are used in construction, industrial, and medical equipment, process technology, machine tools and for measurement and control applications.
ANALOG: A signal whose amplitude can have a continuous range of values. Types of analog output:
Voltage: 0 to 5V or 0 to 10V DC: Full scale output voltage range is fixed as long as the input voltage stays within the specified range (typically 8 to 30VDC, 12 to 30VDC for 0-10V output).
Ratiometric: Output voltage range varies proportional to the input voltage.
Current: 4 to 20mA (This configuration is recommended where the load is in a remote location requiring lengthy wiring, which eliminates output error caused by voltage loss along lengthy cabling).
ANALOG DISPLAY: Type of display whereby the measured value is displayed as part of the entire measuring range..
Angular Resolution: as it refers to inclinometers; resolution is the number of decimals (in degrees) an angle can be measured down to (0.1º, 0.01º, 0.001º or tenths, hundredths, thousandths, etc.). This may or may not be the sole indication of a sensor’s accuracy. See also: resolution, accuracy.
ASCII: American Standard Code for Information Interchange. A 7-bit binary code representing the English alphabet, decimal numbers, and common punctuation marks. It also includes "control characters," such as Carriage Return or End of Text.
attitude: n. [Geology] The orientation of a planar or linear feature in three-dimensional space. Planar features that are not horizontal, such as tilted strata, are described by their strike, or the azimuth of the intersection of the plane with a horizontal surface, and the dip, or the magnitude of its inclination from a horizontal reference. The trend and plunge of linear features, such as the axis of a fold, describe the azimuth of the line and its deviation from horizontal.
See: azimuth, dip, strike.
Avionics: (derived from the expression “aviation electronics”), the development and production of electronic instruments for use in aviation and astronautics. The term also refers to the instruments themselves. Such instruments consist of a wide variety of control, performance, and radio navigation devices and systems. 
azimuth: (or compass heading) (1) n. [Geology] The angle between the vertical projection of a line of interest onto a horizontal surface and true north or magnetic north measured in a horizontal plane, typically measured clockwise from north. Alternate Form: azimuthal. See: attitude, dip, strike, trend. (2) n. [Drilling] The compass direction of a directional survey or of the wellbore as planned or measured by a directional survey. The azimuth is usually specified in degrees with respect to the geographic or magnetic north pole. See: directional drilling, inclination, survey. (3) n. The angle that characterizes a direction or vector relative to a reference direction (usually True North) on a horizontal plane. The azimuth is usually quoted in degrees from 0 to 359.

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 bandwidth: (1) A range within a band of frequencies or wavelengths. (2) The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
Bubble Level: Popular expression for the measuring and display sensors of conventional spirit levels. Bubble levels usually consist of a curved, transparent tube which contains a liquid substance with an enclosed bubble of air. Depending on the inclination of the bubble level, the air bubble changes its position inside the tube indicating the angle of deviation from the vertical or horizontal plain. Bubble levels with a pronounced curvature are less precise, whereas those with a slight bend are more accurate. However, with increasing precision they become harder to read.
 CE: The CE Marking is a symbol that indicates a product complies with the "essential requirements" of the European laws or Directives. It indicates conformity to the legal requirements of the European Union (EU) Directive with respect to safety, health, environment, and consumer protection.
CLINOMETER (cli·nom·e·ter) Pronunciation: kli-'nä-me-ter. Etymology: Greek klinein to lean [klinein to incline + -meter. n. (1) Any of various instruments for measuring angles of elevation or inclination. (2) Any of various surveying instruments for measuring angles of elevation, slope, or incline, as of an embankment. Also called inclinometer. (3) (Geologic) An instrument for determining the dip of beds or strata, or the slope of an embankment or cutting; a kind of plumb level. (4) An instrument used by surveyors in order to measure an angle of inclination or elevation.
[syn: inclinometer]
Compliance Current:  The range of current over which the load regulation is within specified limits.
Compliance Voltage:  The range of output voltage over which the load regulation is within specified limits.
Cross-axis sensitivity or "Angle Orthogonal to the Plane of Measurement": Cross axis sensitivity is a proportionality constant that relates the change of the inclinometer output induced by a cross acceleration/inclination input. The sensitivity can vary depending on the direction of the cross input.
For example: A liquid capacitive gravity based sensor needs to be mounted in a vertical position - if the back of the inclinometer is mounted 45° off of vertical one would expect the inclinometer to be accurate within 0.1° of the expected output when mounted vertical. Due to the unique cavity design the error is predictable without much overall change to the accuracy. The unit will still provide output along the sensor's degree range, however the error at larger cross angle inputs will be significantly higher - as much as 2 or 3 degrees - the further off vertical the sensor is mounted.
CSA International: the Canadian Standards Association, a developer of standards and codes, and QMI for management systems registration.
Current Limit:  The maximum output current which can be drawn from a power supply without causing adverse effects on its operational life. S
 damping: n. The capacity built into a mechanical or electrical device to prevent excessive correction and the resulting instability or oscillatory conditions. v. To slow or stop the vibrations. To decrease the amplitude of (an oscillating system).
data logger: An instrument that logs and/or plots one or more channels of analog or digital data. Data logging may be performed by dedicated instruments or by computer-based data accquisition (DAQ) systems.
decibel: 1. n. The unit of measurement to compare the relative intensity of acoustic or electrical signal, equal to one-tenth of a bel, named for American inventor Alexander Graham Bell (1847 to 1922). The logarithm of the ratio of the sound or signal to a standard provides the decibel measurement. The symbol for the unit is dB. Humans typically hear sounds in the range of 20 to 50 dB in conversation, and upwards of 90 dB when exposed to heavy machinery or aircraft.
digital-to-analog converter (DAC or D/A converter): A device that converts digital information into a corresponding analog voltage or current.
dip: (1) n. [Geology] The magnitude of the inclination of a plane from horizontal. True, or maximum, dip is measured perpendicular to strike. Apparent dip is measured in a direction other than perpendicular to strike.
See: apparent dip, attitude, attribute, azimuth, dip test. (2) n. [Reservoir Characterization] The angle between a planar feature, such as a sedimentary bed or a fault, and a horizontal plane. True dip is the angle a plane makes with a horizontal plane, the angle being measured in a direction perpendicular to the strike of the plane. Apparent dip is the angle measured in any direction other than perpendicular to the strike of the plane. Given the apparent dip and the strike, or two apparent dips, the true dip can be computed.
Dip Test:  Mining: As used in the drilling industry, an angular measurement of the inclination of a borehole taken with a clinometer.
Drift:  The slow change of the output of a power supply with time and/or temperature.
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 EMI:  Electrical disturbances caused by the rapid current changes internal toSMPSes.


 Frequency: (1) n. The rate of repetition of complete wavelengths of electrical signals, light, sound and seismic waves measured in cycles per second, or hertz, and symbolized by f. The rate of a repetitive event. If T is the period of a repetitive event, then the frequency f is its reciprocal, 1/T. Conversely, the period is the reciprocal of the frequency, T = 1/f. Since the period is a time interval expressed in seconds (s), it is easy to see the close relationship between time interval and frequency. The standard unit for frequency is the hertz (Hz), defined as the number of events or cycles per second. The frequency of electrical signals is often measured in multiples of hertz, including kilohertz (kHz), megahertz (MHz), or gigahertz (GHz).

FULL SCALE RANGE: (see also Total Range)

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 gravity: (1) n. The Earth's gravitational field, or the attractive force produced by the mass of the Earth.

 hertz: (1) n. The unit of measurement of frequency, equivalent to one cycle per second and symbolized by Hz.

 INCLINOMETER: (in·cli·nom·e·ter) Pronunciation: "in-kli-'nä-me-ter  n. (1) An instrument used to determine the angle of the earth's magnetic field in respect to the horizontal plane. (2) An instrument for showing the inclination of an aircraft or ship relative to the horizontal. (3) An instrument for showing a deviation from the true vertical or horizontal. (4) An instrument used by surveyors in order to measure an angle of inclination or elevation. 

[syn: clinometer]

INCLINE: n. (1) a slope; v. (1) to (cause to) slope at a particular angle: The ground inclined steeply towards the ridge in the distance.
INCLINATION: n. (1) The deviation from vertical, irrespective of compass direction, expressed in degrees. (2) A small downwards movement (3) The angle at which something slopes.
INTRINSICALLY SAFE: What does it mean to be Intrinsically Safe? The term "intrinsically safe" refers to equipment and wiring which is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most easily ignited concentration. This is achieved by limiting the amount of power available to the electrical equipment in the hazardous area to a level below that which will ignite the gases present. To be certified "intrinsically safe," a device or circuit must be so designed that no two simultaneous failures can cause an explosion.

In order to have a fire or explosion, fuel, oxygen and a source of ignition must be present. An intrinsically safe system assumes that fuel and oxygen are present in the atmosphere, but the system is designed such that the electrical energy or thermal energy of a particular instrument loop can never be great enough to cause ignition. Traditionally, protection from an explosion in hazardous environments has been accomplished either through the use of explosion proof conduits and enclosures (intended to contain an explosion), or via pressurization or purging (intended to isolate the explosive gas from the electrical equipment). Intrinsically safe apparatus cannot replace these methods in all applications, but in many cases can provide significant cost savings in installation and maintenance of the equipment in a hazardous area. The basic design of an intrinsic safety barrier uses diodes to limit voltage, resistors to limit current and a fuse.
IP Ratings: IP (Ingress Protection) ratings are standards for electrical enclosures.
Isolation:  The electrical separation between input and output of a power supply by means of the power transformer. The isolation resistance (normally in megohms) and the isolation capacitance (normally in picofarads) are generally specified and are a function of materials and respective parts location in the power supply.
Isolation Voltage:  The maximum AC or DC voltage which may be continuously applied from input to output and/or chassis of a power supply.
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 KILOHERTZ (kHz): A kHz, or Kilohertz, is a measurement of frequency equal to 1,000 hertz. Kilohertz is unit of measurement for alternating current, audio signals, and a measurement of wireless signals

 LCD: Liquid Crystal Display is a type of display used in digital watches and many portable computers. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light. Monochrome LCD images usually appear as blue or dark gray images on top of a grayish-white background.
A backlit (or transmissive) LCD make it easier to read, in which the pixels are illuminated from behind the monitor’s screen. Transmissive LCDs are commonly used because they offer high contrast and deep colors and are well-suited for indoor environments and low-light circumstances. Transmissive LCDs are at a disadvantage in very bright light, such as outdoors in full sunlight, as the screen can be hard to read.
Leakage Current:  The unwanted current that can flow from any part of an isolated power supply to ground through any convenient conductor. This conductor could be a human body, and could result in serious injury when above certain very low levels. See UL-2601 for acceptable levels for any application.
LED: Light Emitting Diode. A semiconductor light source.
limit switch: A switch that activates when the position of a device crosses a given physical limit.
LINEAR: (Electronics) In electronics, the linear operating region of a transistor is where the collector-emitter current is related to the base current by a simple scale factor, enabling the transistor to be use as an amplifier that preserves the fidelity of output signals. Linear is similarly used to describe regions of any function, mathematical or physical, that follow a straight line with arbitrary slope.
LINEAR RANGE: The maximum angle within the Total Range, where an angular movement produces an equally proportional change in output.
Linearity: Linearity is the behavior of a circuit, particularly an amplifier, in which the output signal strength varies in direct proportion to the input signal strength. In a linear device, the output-to-input signal amplitude ratio is always the same, no matter what the strength of the input signal (as long it is not too strong).
Liquid Capacitive Basics:  The sensing element of Rieker inclinometers use liquid capacitive technology, which is based on gravity. The best way to understand how they work is to think of a disc-like cavity that is half filled with a dielectric liquid. One of the sides of the cavity has an etched conductor plate that is used to form one of the conductors of a variable parallel plate capacitor. The liquid along with the other side of the cavity forms the other plate of the capacitor. In operation, the sensor is mounted so that the disc is positioned perpendicular to the ground (vertically mounted). Gravity then acts on the liquid pulling it down in the cavity forming a semi-circle. As the sensor is rotated the liquid remains in this semi-circular pattern covering a different area of the etched plate. This change in area results in a change in the capacitance. The change in capacitance is then electronically converted into an output signal that is linear with respect to in the input angle.

 milliamperes (mA): . Measure of electrical current. See Ampere.

MIL-STD (Military Standard) or MIL-SPEC (Military Specification): The MIL-STD specification is a series of guidelines established by the U.S. Department of Defense in order to define specific performance and manufacturing requirements for all types of equipment.

MTBF: Mean Time Between Failure. This is an indication of the reliability of a product in normal use. This is a statistical calculation based upon prior history of the parts used in a supply, and their stress levels. Instructions are available in MIL-HDBK-217E.

 NEMA: National Electrical Manufacturer Association. NEMA ratings are standards that are useful in defining the types of environments in which an electrical enclosure can be used.

noise: n. Anything other than desired signal that interfere with output signals. Noise includes disturbances electrical output (EMi), effects of weather and human activity, or random occurrences in the Earth. Noise can be minimized by using source and receiver arrays, generating minimal noise during acquisition and by filtering and stacking data during processing.

Non-linearity: The deviation from a best fit straight line at full scale of true output verses actual.

Noryl® PPO (Modified Polyphenylene Oxide): Noryl® is a strong engineering plastic with outstanding mechanical, thermal, and electrical properties. Low moisture absorption and low thermal expansion make Noryl® one of the most dimensionally stable thermoplastics available. Noryl® is widely used for electrical housings and structural components since it has excellent insulating properties, flame resistance, and dimensional stability over a wide range of service temperatures. Noryl® is often selected for fluid handling applications since it has low moisture absorption and excellent strength and stiffness. Noryl® is easy to fabricate, paint, and glue.

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 OEM: Original equipment manufacturer.

Ohm's LAW: n. The relationship between voltage (V), electric current (I) and resistance (R), named for German physicist Georg Simon Ohm (1789 to 1854), commonly expressed as the formula: V/I = R.

Operating Temperature Range: the temperatures between which the sensor will accurately operate.

 Pitch: The pitch (or Y) axis is perpendicular to the centerline of an object. A pitch motion is an up or down movement (for example) of the nose of the aircraft - the pitching motion is being caused by the deflection of the elevator of this aircraft. This would also be considered a front to back (or fore to aft) tilt in reference to a vehicle or vessel.

potentiometer (resistor): A variable resistor that is used as a transducer for linear or rotary position. Potentiometers may have resistive elements consisting of a variety of materials, including wire-wound, carbon, ceramic-metal alloys (cermet), or conductive plastic.

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Relay output: is a small mechanical dry contact switch. The sensors internal circuit tells the relay to energize or de-energize when a change to the input has occurred. The relay can be wired either normally open or normally closed by reversing the polarity of the circuit.
What is the difference between Relay and a FET? The Relay is a mechanical switch. A tiny arm moves inside the relay providing either an open or closed contact. A FET switch (Field Effect Transistor) is a solid state switch, no moving parts. The FET switch is designed for interfacing to a PLC. The maximum rating for the FET is 36 VDC @ 100mA. The Relay is designed for interfacing directly to a device such as a light buzzer or another relay. The maximum rating for the Relay is 60 VDC/VAC @ 1A.
Repeatability: is the variation in measurements obtained when one person measures the same unit with the same measuring equipment. And/or Repeatability is the variation in measurements obtained when one person takes multiple measurements using the same instrument and techniques on the same parts or items.
Reproducibility: is the variability introduced into the measurement system by the bias differences of different operators.
resolution: The ability to distinguish between separate points or objects, such as decimal points of an angle or output (example: 0.001º or 0.01º) or the smallest change that a sensor can measure. An LCD display can have a resolution of 0.01º or simply a more defined number in reference to a degree of angle. Resolution may be considered in part as a sensor's accuracy but not exclusively. See accuracy, angular resolution.
RFI:  Radio Frequency interference, see EMI.
Ripple:  is the amount of output fluctuation from the rectification of AC to DC. It is measured in volts peak to peak, or volts RMS. Switching power supplies have high frequency ripple, while linear power supplies have low frequency ripple (some multiple of 60Hz).
RoHS Directive: The RoHS Directive stands for "the restriction of the use of certain hazardous substances in electrical and electronic equipment".  This Directive bans the placing on the EU market of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.
ROLL: The roll (or X) axis lies along (or parallel to) an objects centerline. A roll motion is an up and down movement of (for example) the wings of the aircraft - the rolling motion is being caused by the deflection of the ailerons of this aircraft. This would also be considered a side to side (or port to starboard) tilt in reference to a vehicle or vessel.
RS232 interface: Standard serial interface for PC-type computers.
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 Sampling Rate: The number of readings an A/D converter takes per amount of time. For example, 250 readings per second.
Sensitivity: The ratio of output volts to sensor output range or degree (e.g., 200mV/º). Sensitivity allows you to predict the sensor response to a sensor input.
Sensor: n. Any device that receives a signal or stimulus (as motion or inclination, etc.) and responds to it.
SETTLING TIME: The amount of time for the output to stabilize.
Slip Indicator: A "slip" or "skid" or "bank" indicator provides an economic method of determining the lateral differential movement when banking or turning in an aircraft. The bank or slip indicator consists of a curved glass tube filled with a damping liquid in which a small ball rolls. When the craft is horizontal, the ball is located in the lowest part of the tube; as the craft banks, gravity holds the ball at the lowest point as the tube rotates from side to side. The tube can be calibrated to show the angle of banking.
Shock: A short, sharp acceleration. This is specified as the maximum acceleration the product can survive for a given time period. For example: 500 G, 10,000 G / by X Seconds.
SLOPE: n. (1): the angle determined by two lines or planes (2): the angle made by a line with the x-axis measured counterclockwise from the positive direction of that axis.
spirit level: An indicator that establishes the horizontal when a bubble is centered in a tube of liquid
solenoid: An electrically driven actuator. The application of a current results in the motion of a rod or switch.
Solid-State Technology: A term that refers to sensors that do not have moving parts.
strike: 1. n. [Geology] The azimuth of the intersection of a plane, such as a dipping bed, with a horizontal surface.
See: attitude, azimuth, dip.
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 Tilt Switch: Tilt Switches are activated by a change in orientation. A tilt sensor that triggers relay or switch outputs when tilted past a set angle.

TIME CONSTANT: The amount of time it takes, after a stepped angular movement, to produce an output.

total range: (also known as "Full Scale" Range) The largest angler which the sensor or inclinometer can measure.

Transverse Sensitivity: The error in one axis expressed as a percentage of the output in the orthogonal axis. For example, the amount of signal on the X-axis as a function of acceleration along the Y-axis. Transverse sensitivity errors are primarily due to the effects of misalignment.




 XLR Connector: A type of audio signal connector designed and trademarked by ITT-Cannon. The connector specifications dictate a circular connector, lockable, where ground (pin 1) makes first contact to dissipate any static or induced EMF. Male connectors have pins protected by a metal shell. Three-pin XLR connectors are by far the most common style, used for microphone level audio signals, line level audio signals, and balanced digital signals. Configurations can come with as many as seven pins for special signal transfers, such as intercom, data or power. The Switchcraft A, B, C, D and E-series connectors and Neutrik's NC-series connectors are all compatible with the XLR standard.

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 YAW: an aeronautical and nautical term which indicates how far a craft is pointing away from its direction of travel due to rotation about its vertical axis. Rotations about the other axes are called pitch and roll. [aerodynamics] The yaw (or Z) axis is perpendicular to the wings and lies in the plane of the aircraft centerline. A yaw motion is a side to side movement of the nose of the aircraft, caused by the deflection of the rudder. See Azimuth.


More to come...

Please contact us today with your specifications and application requirements for your slip indicator needs. One of our engineers will be happy to speak with you. 

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Rieker Inc.
34 Mount Pleasant Rd
Aston, PA 19014
Ph: (610) 500-2000
Fax: (610) 500-2002
Toll Free: (800) 497-4523
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