Function Key Labels
Labels shown on the bottom display that indicate the function of the function keys
to .
Function Key Menu
The function key labels listed on the bottom display.
Glitch
A momentary spike in a waveform. This can be caused by a momentary disruption in
the circuit under test.
Glow plug
A combustion chamber heat generating device to aid starting diesel engines.
Governor
A device designed to automatically limit engine speed.
Ground
An electrical conductor used as a common ret urn for an electric circuit(s) and with a
relative zero potential.
Ground Controlled
A circuit that is energized by applying ground; voltage has been already supplied.
Circuit
Hall-Effect Sensor
A semiconductor moving relative to a magnetic field, generating a variable voltage
(or Hall Sensor)
output. Used to determine position in the automotive industry.
Idle
Rotational speed of an engine with vehicle at rest and accelerator pedal not depressed.
Ignition
System used to provide high voltage spark for internal combustion engines.
Inductance
The signal caused by a sudden change of a magnetic field.
For example, when you t urn off the current through a solenoid, a volt age spike is
generated across the solenoid.
Intake Air
Air drawn through a cleaner and distributed to each cylinder for use in combustion.
Intermittent
Irregular, a condition that happens with no apparant or predictable pattern.
Invert
To change to the opposite polarity. Puts the waveform display upside down.
Knock (Engine)
The sharp, metallic sound produced when two pressure fronts collide in the combustion
chamber of an engine.
Lamda Sensor
Oxygen (or O
2
) sensor.
LCD
Liquid Crystal Display
Link
General term used to indicate the existence of communication facilities between two points.
(Electrical/Electronic)
Manifold
A device designed to collect or distribute fluid, air or the like.
Master Reset
Resets the instrument to the factory “Default Setup”.
You can do this by turning power on while pressing the F5 function key ( ).
Menu
A list of choices for selecting a test, a function, or a setting.
Malfunction Indicator
A required on-board indicator to alert the driver of an emission related malfunction.
Lamp (MIL)
Noise
Extraneous electrical signal that can interfere with other electrical signals. The noise can
disturb the function of the signal when it exceeds a certain electrical level.
G-3
Cursor
A vertical or horizontal line (kind of ruler) that you can place on the screen and move
horizontally or vertically to measure values at certain points of the waveform.
DC
Direct Current
DC Coupling
A mode of signal transmission that passes both AC and DC signal components to the
input (INPUT A or INPUT B) of the instrument.
Default Setup
The setup that exists as long as there are no changes made to the settings.
Diesel Probe
A test probe that has a pickup element to measure the pressure pulse in the diesel fuel
pipe. It converts fuel pipe expansion into voltage.
Differential
Measurement of the difference between the waveform sample values at the positions of
Measurement(Delta)
the two cursors.
Diode
An electrical device that allows current to flow in one direction only.
Direct Current
A signal with constant voltage and current
DIS
Distributorless Ignition System
Division
A specific segment of a waveform, as defined by the grid on the display.
Drive
A device which provides a fixed increase or decrease ratio of relative rotation between
its input and output shafts.
Driver
A switched electronic device that controls output state.
Duty Cycle
On-time or off-time to period time ratio expressed in a percentage.
Earth Ground
A conductor that will dissipate large electrical currents into the Earth.
ECM
Electronic Control Module on a vehicle.
ECU
Electronic Control Unit on a vehicle.
EIA-232-D/RS-232C
International standard for serial data communication to which the optical interface of the
instrument conforms.
Electromagnetic
Mutual disturbance of signals, mostly caused by signals from adjacent wiring.
Interference
EMI
Electromagnetic Interference
Feed Controlled Circuit A circuit that is energized by applying voltage; it has already been grounded.
Filter
E lect rical circuits or device that only passes or blocks certain signal frequencies. A n
application can be to remove noises from a signal.
Freeze Frame
A block of memory containing the vehicle operating conditions for a specific time.
Frequency
The number of times a waveform repeats per second, measure in Hz. 1 Hz equals one
cycle per second.
Fuel Trim
A set of posit ive and negat ive values that represent adding or subtracting f uel from
engine. A fuel correction term.
G-2
Terminology
Description
Terminology
Description