Term

Definition

0...9

100 Harmonics

Mode in which 100 harmonics + DC - Part of U, I and P are calculated.

A

AAF

look Anti Aliasing Filter.

AC

Alternating current; instantaneous values of voltage and current are time depending signals which have positive and negative values.

AC coupling

Used to remove the DC parts of a signal by using a high pass filter.

AC+DC coupling

Couples the complete signal without rejecting any parts.

Accuracy

Declaration of the errors which will be made in measuring.

Active energy

Energy which is consumpted by the load (ohmic part).

Active power

Power which is consumpted in the load (ohmic part).

Actual flicker level Pmom

look Instantaneous flicker level.

Aliasing

Distortion caused by signal parts, which are created through the violation of the sampling (Nyquist, Shannon) theorem (bandwidth ³ 1/2 sampling frequency). This can be prevented by using look Anti Aliasing Filter.

Allowed limits

Limits which are declared in standards.

AM

Amplitude modulation; one signal is multiplied with another one; A typical example is a burst fire control, where a 50Hz sine wave is modulated with a slower rectangular signal.

Amplitude error

Error in the modulus of a measuring result.

Amplitude modulation

look AM.

Analogue I/O

Analogue input and output, the LMG series supplies eight separated inputs and outputs for analogue signals: 0-10V.

Analogue Input

look Analogue I/O.

Analogue Output

look Analogue I/O.

AND Condition Register

Register in which a flag is set, if two conditions are true.

Anti-Aliasing-Filter

Filter which cuts off signal parts which might produce aliasing.

Apparent energy

Energy which seems to be consumpted by the load; look Apparent power. It is the integration of the apparent power.

Apparent power

Power which seems to be consumpted; it is calculated by U_TRMS * I_TRMS without taking care on the phase angle between them.

Application note

Several measuring or wiring problems are described in application notes of ZES ZIMMER; available also at the ZES homepage: www.zes.com.

Arbitrary block response data

look Defined length arbitrary block response data.

ASCII format

Format which bases on the American standard code of information interchange with 128 symbols.

Auto range

Function which changes the ranges of the current and voltage inputs automatically, depending on the signal.

Auxiliary transducer supply

Some transducers need a separate supply. The LMG can provide this supply.

Averaged values

This values are averaged over a constant number of measuring cycles, more stable display.

B

Bandwidth

Frequency range from the lowest to the highest frequency, which can be measured or used.

Bargraph

Display of the values symbolised by bars; A typical bargraph is the spectrum display.

Basic wave

The signal part with the lowest frequency in the signal (except DC part). Also called look fundamental.

Baud rate

Transfer speed of the bits in a serial data stream (Bits per second).

Binary

Numerical system based only on to values: 0 and 1, the data is represented only by this two binary values.

Bitmap

Format of drawing or photos (*.bmp).

Burden

Maximum resistance of a current transducer including wiring and input resistance.

C

Calibration according to ISO9000

Testing of the meter accuracy traceable to national or international standards.

Capacitance against earth

Each channel has a capacitance against the earth ; this can cause systematically measuring errors which can be corrected.

CAT II

Overvoltage class for usage in normal building nets.

CAT III

Overvoltage class for usage at the PCC (point of common coupling)

CE harmonics

Harmonics measured according to EN61000-3-2; this test is requested for the CE sign.

CE-Flicker

Flicker measured according to EN61000-3-3; this test is requested for the CE sign.

Channel

Hardware which acts as an interface between the test circuit and the instrument, these are U, I and P channels (P=U*I).

Charge

The integration of the current over the time; this charge can be stored for example in an accumulator the unit is Ah or As.

Class A, B, C, D

Different kinds of equipment under test for EN61000-3-2 tests are assigned to this test classes.

COM interfaces

Serial Interface, mostly 9 pole SUB-D socket or 25 pole SUB-D socket.

Comma separated

Data format in which each value is separated by a ‘,’ e.g. par1, par2.

Command set

A couple of commands to remote control the instrument

Common mode rejection

Relation of the displayed value to a common floating signal on all inputs of a measuring channel; a high common mode rejection is necessary for high accuracy.

Condition instruction

Instruction which will only be executed if a condition has been fulfilled.

Constant

Value which will not change over time.

Continuous measuring

Measuring without any gaps.

Core parameter measuring circuit

The core parameters, like hysteresis and magnetic flux, can be determined through power measuring.

Correct current
Correct voltage measuring

You can only measure one of these parameters in the correct way, because the impedance of the voltage / current channel has an influence on the measuring channel. This is a systematically measuring error, which can be corrected.

Coupling

This defines which parts of a signal are fed into the next stage. look AC coupling.

Crest factor

Ratio of peak value to TRMS value; very important when using analogue instruments.

Current clamp

Tool to measure currents; work like a removable transformer.

Current transducer

Similar to current clamps, but placed unremovable in the measurement circuit.

Cursor

Representation of the place on which the next text input will follow; in graphics the cursor marks a special point of the waveform.

Custom menu

Menu defined by the customer himself.

Cycle time

Time which defines a measuring cycle must be higher than the period time of the basic wave.

D

D. U. T.

‘Device under test’: equipment which should be measured.

Data output format

Format which is used to transfer data from the meter to a PC or data logger.

DC value

‘Direct current’; signal without alternating components. This signal is constant over the time.

Default parameters

Parameters defined by the manufacturer; the instrument is set to this parameters when it leaves the factory.

Defined length arbitrary block response data

Data transfer in blocks with a defined length and random contents inside the blocks; there can be for example the look EOS character which will be interpreted as data instead of EOS. The fastest way to get data.

Demodulation

Inverse function to look modulation; remove the carrier and you get the signal you want.

Desired integration time

Time in which the power is integrated, set by the user.

Device

Every meter or equipment take place in the measurement (Printer, PC ...).

Device under test

look D. U. T.

DFT algorithm

Discrete Fourier transformation; operation with discrete values using the Fourier integral to get the harmonics of a signal.

Digital filter

Filter built up with digital components and software.

Digital Input

Like look Analogue inputs the LMG series provides digital inputs, to read external states.

Digital Output

Like look Analogue outputs the LMG series provides digital outputs, which can be used to signalise states (e.g. alarm outputs).

DIP switches

Small hardware switches to set up a meter parameter, like communication speed.

Direction input

Input for motor testing to measure the rotary direction of the motor.

Dot joiner

Connects the dots of the measured graph; it improves the look of a graph.

E

E. U. T.

look D. U. T.

Echo

Repetition of characters sent via the RS232 to the instrument.

Edit line

Line in which you can change a value or text.

Efficiency measurement

Efficiency is the relation between the output power and the input power of an E. U. T.

EN61000-3-2, EN61000-4-7
EN61000-3-3, EN61000-4-15

Standards which describe the harmonic measuring
Standards which describe the flicker measuring.

End of string character

‘<lf>‘, ‘<cr>, <cr><lf>‘ are examples for EOS characters.

Energy

Integration of the power which is consumpted by a consumer or a device in a defined time.

Envelope

It is the curve which covers a mixed frequency signal connecting the peak values of the fast frequency; a curve defined by EN61000-3-2 to define if a device belongs to Class D or not.

EOS

look End of string.

Equipment under test

look D. u. t.

ESC key

Key used to cancel an entering mode and to quit an error message.

Extended Trigger

Mode in which the trigger conditions can be set up very differentiated to measure even modulated signal.

External current transformer

Device to transform high currents to lower ones.

External shunt

Changes currents into voltage with defined ratio.

External synchronisation jack

Input for an external synchronisation source.

F

Falling edge

Opposite of rising edge; the logic signal turns from the high potential to the lower one.

FIFO

First in first out; method how the in- and output of memory is handled.

Filter

Device which cuts off frequencies which are not useful; e.g. high pass filter cut off low frequencies.

Flicker meter

Device to measure flicker levels.

Fluctuating harmonics

Harmonics not constant over time.

Form factor

Ratio of TRMS value to rectified value; older meters could only measure the rectified value and multiply it with the form factor to get the TRMS value. The problem is, that the form factor depends on the waveform. So with other waveform you get an error. Modern instruments like the LMGs measure independent to the form factor, so you measure always correct.

Formula editor

Here you can set up formulas which will calculate different parameters from the measured values.

Freeze

The display values are not updated any more.

Frequency

Speed in which the period of an alternating signal repeats.

Frequency divider

Changes a high frequency into lower frequency by division with an integer number.

Frequency range

look Bandwidth.

Full scale value

Highest measurable instantaneous value in the chosen range.

Fundamental

look Basic wave.

G

GPIB interface

General Purpose Interface Bus socket to transfer data from meter to PC and opposite look IEEE.

Graphical display

Representation of the measured values via time or frequency.

H

Half wave value

Values measured over the half time of the signals period.

HARM100

look 100 Harmonics.

Harmonic analyser

Device to measure harmonics.

Harmonic order

Describes which order the harmonic has; e.g. of a 50Hz signal the order of the 100Hz harmonic is 2, its the second harmonic.

High impedance state

The digital output has a high impedance; the transistor is in blocking mode.

Hyperterminal

Software to exchange data between a PC and a device; included in Microsoft Windows.

Hysteresis

A retardation of the effect when the forces acting upon a body are changed (as if from viscosity or internal friction); e.g. a lagging in the values of resulting magnetisation in a magnetic material (as iron) due to a changing magnetising force.

I

I/C indication

Indication if the load is inductive or capacitive.

Identifier

Text string representing a measuring value.

IEC61000-3-2, 2-3

look EN61000-3-2.

IEC61000-4-7, -4-15

look EN61000.

IEEE488.2 interface

look GPIB interface.

IF/IO

Key for the set - up menus of interface and processing signal interface.

Inaccuracy of display

Because of the limited numbers on the display the displayed values have an error caused by the display (this is always ± 1 digit).

InCa flag

Flag which is set depending if the load is inductive or capacitive.

Input resistance Ri

Resistance of the input of the measuring channel.

Inrush current

Very high current at the start of a device or appliance; this can be up to 100 times bigger than the current at normal operation.

Instantaneous flicker level

Time-dependent output signal of a flickermeter (output 5), which simulates an actual reaction of men’s brain to the variations of light brightness caused by fluctuation of the supply voltage.

Instantaneous value

The value of a signal at one point of time.

Int. Time

Interval time; for example for integration.

Int. Value

Interval value; they are measured while the look Int. Time.

Integer number

Number without decimal position.

Integration mode

Mode in which the energy is calculated.

Interface

Adapter for the connection between two devices.

Interharmonic

Sinusoidal components with a frequency which is not an integer time of the fundamental.

Internal beeper

Like the PC speaker; to signalise errors.

Interval

Fixed time period.

ISO9000

Standard to guarantee the quality of devices or appliances.

L

Level

Height of a value.

Logical devices

Log or remote; if log printer, RS232 or MCM is meant, is the question of the physical device.

Limit

Border of a value.

Linefeed

<lf>, hex0A, dec10; jump to the next line; historical from a typewriter, is the most common look EOS character.

Local

In this mode the LMG can be controlled directly by the user at its keyboard; look Remote control.

Logarithmic display

Display scaled with logarithmic axis.

Logging

Store data to memory, printer or any other storage device.

Long number

4 Bytes.

Long term flicker level Plt

A result of weighted averaging of short term flicker levels over a time period which typically equals to 2h.

Loop area

Inner area of a circle is a loop area.

Low-Pass Filter

Cuts off high frequencies.

M

Mains

Line supply.

Mains switch

Switch to start up the instrument.

Manual range

The range settings have to be done by the user.

Measuring converter

Adapter to connect a meter to the look D. U. T.

Measuring cycle

Cycle set up from the user. After this time the meter calculates new values. The exact time depends on the synchronisation frequency.

Measuring settings

All parameters of the meter which influence the measurement.

Memory card

Random access memory card to store data.

Menu

The whole measurement settings are divided in menus to get a better survey.

Miscellaneous

In this menu you can set up several parameters which have no direct influence on the power measurement, like contrast time and date.

Multimeter

Meter which can measure several values like voltage, current and resistance.

N

Nibble

Half of a byte; upper or lower 4bit.

Noise

Usually random signals with a high bandwidth which are superposed to the useful signal.

Nondecimal numeric program data

Data which can be represented as string instead of a number; e. g. ‘Cont on’ instead of ‘Cont 1’.

Null modem

Type of serial connection between a PC and another device; the connection cable has two crossed conductor pairs.

O

Open collector outputs

Passive outputs where the user has access to the collector of the output transistor. You have to connect an external voltage supply to this collector to use the output.

Operator

Instruction which is taken into the calculation: +, -, *, /.

Option Key

A string which can be used to implement software options when the LMG is at the customer.

OR Condition Register

Register which becomes true if an or condition is fulfilled.

Order

look Harmonic order.

Overload capability

A value how much a channel can be overloaded for a certain time.

Overload condition

The instrument is in overload condition while the applied signal is too big for the selected range.

P

Packed

Data are transferred binary instead of ASCII format

Parallel interface

look Serial interface; here the data is transferred in parallel.

Parity

Even or odd number of 1’s in a binary data block; The LMG works without parity.

Parsing

The LMG tries to interpret a formula or interface string and to react correctly.

Partial odd harmonic current

The harmonic content of order 21, 23 ...

PCMCIA memory cards

look Memory card; PCMCIA is the old name for the PC - Card standard.

Peak current ranges

Ranges with quiet small allowed TRMS values (because of the heating up of the shunt) but very big allowed peak values; very useful to measure look Inrush currents.

Peak value

Value measured from the zero line to the highest peak of the signal.

Peak-peak value

Measured from the lowest to the highest peak of a signal.

Periodic integration mode

In this mode the integration interval is repeated periodically.

Phase

Conductor of the high potential; typically marked with L.

Phase angles

Usually the angle between current and voltage.

Phase error

The error in power caused by an additional phase shift in the measuring equipment, for example the additional phase shift of a current clamp.

Physical device

Hardware, device (RS232, printer, GPIB...).

Plot function

Mode in which cycle values (e.g. voltage, frequency, ...) are displayed over time.

Power

The energy of a time interval divided by the internal time (e.g. cycle time); so the power is always an averaged value!!

Power factor

Relation between active and apparent power.

Power measuring channel

look Channel.

Power supply

Source which provides the necessary voltage.

Pretrigger

Time before the trigger condition, while which sample values are stored.

Printer header

Upper line of the printer like a title or headline.

Printer output

Socket to connect a printer.

Processing signal interface

Board with Analogue or Digital outputs.

Protocol

Arrangements for communication between devices.

Pulse controlled currents

A modulated current controls the device’s power; like in a hot air fan the rapid fire control.

R

RAM

Random access memory; you can read and write to this memory.

Range

The measuring range defines the biggest measurable signal. For best accuracy the range should be used for at least 66%.

Reactive energy

Energy which oscillates between source and load without being consumpted.

Reactive power

Average look Reactive energy.

Real measuring time

Time in which the measuring is made, depends on look cycle time and look synchronisation frequency.

Record rate

Ratio in which the sampled values are stored in memory.

Rectified value

The average value of a rectified signal; measured by many analogue instruments look form factor.

Remote control

You can control the LMG via a connection to a PC.

Resolution

Resolution is not look Accuracy!!! In the LMG are two resolutions important: the analogue to digital converter has 16bit resolution, the display has 5 or 6 digit resolution.

Rise time

Time in which the signal rises from zero to the maximum (in practice from 10% to 90%).

Rotary knob

Knob used to set up parameters in the meter or move the look Cursor.

Rotation speed

Speed of the shaft of a motor; rpm.

RS232 interface

look Serial interface.

RTS/CTS

look Protocol to control the data flow of a look Serial interface.

 S

Safety socket

Connection with high safety against electric shock.

Sample memory

Memory to store the sampled measurement values.

Sample value

Value of a signal measured at a defined time look Instantaneous Value.

Sampling frequency

Frequency with which the samples of a signal are taken.

Scaling

Resolution of an axis or factor which has an influence on the measured value.

Scope function

In this mode the LMG works like an oscilloscope and displays look Sample values.

SCPI commands

A standardised set of commands to remote control the LMG.

Sensors

A small external device which converts a current or voltage to a signal the LMG can measure.

Serial poll

A PC program can ask every connected instrument in series if it has data to send. Used by look GPIB.

SHORT headers

Shorter set of commands, equivalent to look SCPI.

Short term flicker level

A result of statistical processing of instantaneous flicker level quantities over a time period, which typically equals to 10 min.

Shunt input

Special socket to connect the small voltages of an external shunt to the correct channel.

Shuttle knob

look Rotary knob.

Signal coupling

look AC coupling; This coupling affects the measured values.

Signal source

Where you get a signal from; e.g. frequency generator.

Slewrate

Relation between the voltage risen and the used time.

Softkey

This keys change the meaning depending on the menu.

Software options

Options which can be installed with software.

Software update

Updates your software of the LMG. Available on the homepage: www.zes.com.

Status byte register

Register in which several flags are set according to the status of the LMG.

String

Characters lined up in a row.

Sub menu

A subdivision of a menu.

Synchronisation

Periodic signals have to be measured for an integer number of periods. So the LMG must synchronise it’s measuring to the signal to get stable values.

System time

Main time of the meter.

T

Table

Special format for output of measuring values in a table.

Terminal

Each device which takes an account on a data transfer.

Terminal program

look Hyperterminal.

THD values

Total harmonic distortion, relation of the harmonics of a signal to the fundamental.

Time depended signals

Signal of which the values change depending on the time.

Time domain views

Values are displayed over time.

Total Harmonic Current

Sum of all harmonics starting with 2nd order.

Total harmonic distortion

look THD.

Total harmonic distortion factor including noise (THD+N)

look THD with included noise.

Transient

A short, unusual event on a signal.

Transient mode

Mode in which events can be recorded.

Trigger condition

The trigger starts depending on this condition.

Trigger level

Level on which the trigger starts.

Trigger signal

Signal which gives the trigger event.

TRMS

look True root mean square.

True root mean square

The average of a squared signal.

V

Variables

Values calculated by look Formula Editor.

Visual display

Display what you can see in the moment.

Voltage transformers

Changes voltage levels.

Z

Zero crossing

When the signal passes the zero axis. The positive zero crossing is usually used for look Synchronisation.

Zoom

Zoom in: enlarge the display
Zoom out: reduce the visual display.