Laplace instruments Ac2000a User manual

LAPLACE INSTRUMENTS LTD

AC2000A

USER MANUAL

ISSUE 14

LAPLACE INSTRUMENTS LTD

Tudor House, Grammar School Road,

North Walsham, Norfolk NR28 9JH

T: +44 (0) 16 92 40 20 70

E: tech@laplace.co.uk

W: www.laplace.co.uk

Table of Contents 
This manual is 48511-0400 Issue 14 and describes firmware version 3.0 or later. 
1 
 
 
 Introduction 2 
Specification 3 
Safety 5 
Installation 6 
Connections 7 
Front Panel Connections 7 
Rear Panel Connections 7 
Initial Operation 8 
Power Meter View 10 
Power Meter Set-up 12 
Waveform Graph View 13 
Waveform Graph Set-up 14 
Harmonics View 17 
Harmonics View Set-up 18 
Display Format - Histogram 18 
Display Format –Tables 21 
Test Control View 23 
Test Control Set-up (Harmonics) 24 
EN61000-3-3 Flicker and Fluctuations 29 
Test Control Set-up (Flicker) 31 
Meter View (Flicker) 33 
Flicker Meter Page 33 
Voltage Variation Page 34 
Peak Inrush Current Measurement 36 
Test Control Set-up (Peak Inrush Current) 38 
Report View 39 
Report Formats 40 
Report Set-up 43 
Compliance Measurements with the AC2000A 45 
Overview of Harmonics Measurements 45 
Taking Harmonics Measurements 46 
Taking Flicker and Fluctuation Measurements 48 
HA-PC Link Plus Software 49 
Software Installation 49 
Operation of the HA-PC Link Plus Software 49 
Exporting and Formatting Reports with a Word Processor 52 
Installation of USB drivers 54 
Maintenance & Calibration 55 
Firmware Updates 56 
Note: The latest revision of this manual, firmware, device drivers and software 
tools can be downloaded via: http://aimtti.com/support 

Introduction

High performance power analyser

The AC2000A is a high speed, high accuracy AC power analyser for single phase supplies of up

to 16 Amps rms.

The supply to be measured is connected via a dedicated input cable independently of the supply

to the instrument. The output to the load is via a front panel mounted 'standard' mains connector.

A wide range of power connectors is available including most European national types.

The AC2000A can measure Watts, VA, Volts rms, Volts peak, Amps rms, Amps peak, Crest

factors, THD, Power factor, Frequency and Inrush current.

The large display can show multiple parameters simultaneously along with graphical

representations of voltage and current waveforms.

Dual 16 bit Analog to Digital converters continuously sample both voltage and current and give a

wide dynamic range. A fast Digital Signal Processor gives the performance needed for

continuous real-time analysis of the data. Advanced algorithms yield accurate results, using

extended precision or floating point arithmetic wherever necessary.

Compliance-quality harmonics analyser

The AC2000A has been designed to make harmonics measurements both quick and

simple. It measures harmonics from the 1st to the 40th and updates the display in real time.

It is suitable for pre-compliance measurements using a normal mains supply and is capable of

full compliance measurements to EN61000-3-2 in conjunction with a suitable power source (such

as the AC1000A).

Capabilities include continuous monitoring of the supply voltage, continuous comparison to

harmonic limits and timed test sequences with analysis of fluctuating harmonics.

Compliance-quality flicker meter

The AC2000A has the capability to operate as a compliance quality voltage variation and flicker

meter in conformance with EN61000-3-3 and EN61000-4-15.

Flicker severity can be measured in terms of Pst and Plt while simultaneously performing full

analysis of voltage variations, including the calculation of dc (the largest difference between

steady states), dmax (the maximum voltage difference during a change interval), and tmax (the

cumulative duration over a specified value during a voltage change characteristic).

For pre-compliance testing, a current measurement method can be used, rather than voltage

measurement, to eliminate the need for a clean power generator and a reference impedance.

A full range of interfaces

A parallel printer interface is included, for record keeping and archiving, and also a high speed

RS-232 interface is provided for use with either a printer or remote control software running on a

PC. The AC2000A also has a USB port for use with the HA-PC Link Plus software.

The internal software of the instrument is stored in flash memory and can be updated through the

serial port as the requirements of the measurement standards evolve.

AC2000 and AC2000A

The two versions of the instrument are in different cases, with slightly different front panel

layouts. The AC2000A has a USB port. In all other respects the operation and performance of the

two types is identical. Both use the same firmware, and this manual applies to either type if fitted

with firmware version 3.00 or later.

Specification

MAINS ANALYSER

Measurement Circuit:

Single Phase with standard mains connector.

Current Rating:

16A rms continuous, or national connector rating if lower.

Voltage Ranges:

115V (± 200V pk) and 230V (± 400V pk).

Current Ranges:

± 24mA pk to ± 400A pk in fifteen 2:1 ranges.

Frequency Range:

43 –67 Hz.

Shunt Resistance:

3m.

Sampling Rate:

300 points per cycle.

Basic Accuracy:

Better than 0.2% ±1mA, up to 16A.

Measured Parameters:

Vrms, Vpk, Arms, Apk, Crest factors, THD, W, VA, Power factor, Frequency,

Peak Inrush current.

Display Modes:

Tabular display of all parameters including latest and highest inrush current.

Waveform Graph display of Voltage and Current with normal, Max hold,

accumulate and multiple cycle display modes.

Monitor Outputs:

Re-constructed Voltage and Current Signals.

HARMONICS ANALYSER

Measurements:

1st harmonic to 40th harmonic.

Measurement processing to EN61000-3-2. and EN61000–4–7

Continuous calculation, analysis and assessment of unfiltered, filtered,

average, minimum and maximum current harmonic levels and limits.

Continuous measurement and assessment of supply waveform and

harmonics.

Current Rating:

16A rms continuous, or national connector rating if lower.

Voltage Ranges:

115 (± 200V pk) and 230V (± 400V pk).

Current Ranges:

± 24mA pk to ± 400A pk in fifteen 2:1 ranges.

Frequency Range:

43 –67 Hz.

Shunt Resistance:

3m(less than 150mV across shunt up to 50 Amp peak).

Transform Windows:

Continuous 4, 10, 12 or 16 cycle Discrete Fourier Transforms.

Basic Accuracy:

Better than 5% of limit or 0.2% of selected range (whichever is the greater)

±1mA.

Display Modes:

Display of load supply assessment for voltage, harmonics, crest limits and

frequency against requirements defined in EN61000-3-2.

Histogram or tabular display of supply voltage harmonics.

Histogram display of current harmonics with limits (calculated from EN61000-

3-2), with Min. hold, Max. hold and percentage of limit display options.

Tabular display of current harmonics showing present values, limits, average

values, average as percent of limit, maximum values, maximum as percent of

limit and pass or fail assessment for each harmonic.

Test Control:

Untimed, manually timed or automatically timed tests; user-defined test time.

Declaration of load class. Limits automatically determined from EN61000-3-2

for appropriate class; Class C and Class D limits can be automatically

calculated from power measurements or from ratings declared by the user.

Minimum and maximum power thresholds for limits can be changed by the

user.

Facility for declaring supply voltages other than 230V and deriving

appropriate limits. Facility for insetting test limits.

Report Printing:

Direct printer connection for hard-copy report with user-entered narrative,

supply voltage assessment and current harmonic analysis and assessment.

VOLTAGE FLUCTUATIONS & FLICKER METER

Measurements:

Voltage fluctuations dc, tmax and dmax and flicker Pst and Plt

to EN61000-3-3 and EN61000-4-15.

Current Rating:

16A rms continuous, or national connector rating if lower.

Voltage Ranges:

115V (± 200V pk) and 230V (± 400V pk).

Fluctuation Range:

25% max (relative to nominal voltage).

Flickermeter Range:

Voltage change up to 20% (sinewave change) or 10% (low repetition rate

rectangular change) relative to AGC level.

Equivalent to 6400 pu on 8.8 Hz sinewave.

Flickermeter AGC:

Up to ±5%.

Flickermeter Accuracy:

Better than 5% for Pst range 0·7 to 10·0.

Frequency Range:

50Hz (operates over 43 –67 Hz).

Report Printing:

Tabular listing of voltage variations, Pst classifier and Pst in each Plt interval.

GENERAL

Display:

320 x 240 pixel backlit LCD.

Clock:

Real−time clock for time and date−stamping of Report data.

Interfaces:

Parallel Printer, RS-232 (for printer or PC); also USB (for PC) on AC2000AA.

Instrument Supply:

220V–240V or 110V–120V ±10%, 48 to 65Hz. Installation Category II.

Maximum instrument power 25VA. The instrument can be operated at a

different supply voltage and/or frequency from that used to supply the load.

Operating Range:

+5°C to 40°C, 20-80% RH.

Storage Range:

–10°C to +60°C.

Environmental:

Indoor use at altitudes up to 2000m, Pollution Degree 2.

Safety & EMC:

Complies with EN61010-1 & EN61326-1.

Dimensions (WxHxD):

AC2000A: 357 x 132 x 235mm; AC2000: 305 x 148 x 220mm.

Weight:

AC2000A: 4.4kg; AC2000: 4.2kg.

Safety

This instrument is Safety Class I according to IEC classification and has been designed to meet

the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for Measurement,

Control and Laboratory Use). It is an Installation Category II instrument intended for operation

from a normal single phase supply.

This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe

condition. This instruction manual contains some information and warnings which have to be

followed by the user to ensure safe operation and to retain the instrument in a safe condition.

This instrument has been designed for indoor use in a Pollution Degree 2 environment in the

temperature range 5C to 40C, 20% - 80% RH (non-condensing). It may occasionally be

subjected to temperatures between +5° and -10°C without degradation of its safety. Do not

operate while condensation is present.

Use of this instrument in a manner not specified by these instructions may impair the safety

protection provided. Do not operate the instrument outside its rated supply voltages or

environmental range.

WARNING! THIS INSTRUMENT MUST BE EARTHED

Any interruption of the mains earth conductor inside or outside the instrument will make the

instrument dangerous. Intentional interruption is prohibited. The protective action must not be

negated by the use of an extension cord without a protective conductor.

When the instrument is connected to either supply, terminals may be live and opening the covers

or removal of parts (except those to which access can be gained by hand) is likely to expose live

parts. The apparatus shall be disconnected from all voltage sources before it is opened for any

adjustment, replacement, maintenance or repair.

Any adjustment, maintenance and repair of the opened instrument under voltage shall be

avoided as far as possible and, if inevitable, shall be carried out only by a skilled person who is

aware of the hazard involved.

If the instrument is clearly defective, has been subject to mechanical damage, excessive

moisture or chemical corrosion the safety protection may be impaired and the apparatus should

be withdrawn from use and returned for checking and repair.

Make sure that only fuses with the required rated current and of the specified type are used for

replacement. The use of makeshift fuses and the short-circuiting of fuse holders is prohibited.

This instrument uses a Lithium button cell for the real-time clock and non-volatile memory battery

back-up; typical life is 3 years. In the event of replacement becoming necessary, replace only

with a cell of the correct type, i.e. 3V Li/Mn02 20mm button cell type 2032. Exhausted cells must

be disposed of carefully in accordance with local regulations; do not cut open, incinerate, expose

to temperatures above 60°C or attempt to recharge.

Do not wet the instrument when cleaning it and in particular use only a soft dry cloth to clean the

LCD window. The following symbols are used on the instrument and in this manual:-

Caution -refer to the accompanying documentation, incorrect

operation may damage the instrument.

Terminal connected to chassis ground.

Alternating current.

Mains Operating Voltage –Instrument Power

Installation

Before making connections to the AC line source ensure that the operating voltage of the

instrument is correctly set. The operating voltage is indicated by the orientation of the fuseholder.

When the 230V marking is upwards, the unit is set for operation over the range 220V to 240V.

When the 115V marking is upwards, the unit is set for operation over the range 110V to 120V. To

change the operating voltage range, remove the AC line plug, pull out the fuse holder, replace

the fuse with one of the appropriate rating (see below) and rotate the fuse holder before pushing

it firmly back into place.

Safety Note: To fully disconnect the Instrument Power from the AC supply, unplug the mains

cord from the INSTRUMENT POWER inlet or from the AC supply outlet.

Mains Operating Voltage –Load Power

The fixed LOAD POWER mains lead is an independent connection, which provides power to the

appliance connector on the front panel; it can be at a different voltage and frequency from the

instrument power. The maximum permitted load power voltage is 264Vrms and the frequency

range is 43 - 67Hz.

For full compliance measurements to EN61000-3-2 the load power lead should be connected to

an AC supply that meets the voltage, frequency and harmonics requirements defined in the

standard; the AC1000A low distortion power source can be used for this purpose.

Safety Note: To fully disconnect the Load Power from the AC supply, unplug the mains cord

from the AC supply outlet.

Fuse –Instrument Power

The correct time-lag fuse must be fitted for the selected operating voltage.

For 230V operation use 250mA (T) 250V time-lag HBC

For 115V operation use 500mA (T) 250V time-lag HBC

Make sure that only fuses with the required rated current and of the specified type are used for

replacement. The use of makeshift fuses and the short-circuiting of fuse holders are prohibited.

Fuse –Load Power

A high voltage, high breaking current, fuse is fitted internally in the load power circuit. The correct

fuse type is: 20A 500V HBC Type aM or gL.

Make sure that only fuses with the required rated current and of the specified type are used for

replacement. The use of makeshift fuses and the short-circuiting of fuse holders are prohibited.

Mains Lead

Connect the instrument to the AC supply using the mains lead provided. Should a mains plug be

required for a different mains outlet socket, a suitably rated and approved mains lead set should

be used which is fitted with the required wall plug and an IEC60320 C13 connector for the

instrument end. To determine the minimum current rating of the lead-set for the intended AC

supply, refer to the power rating information on the equipment or in the Specification.

WARNING ! - THIS INSTRUMENT MUST BE EARTHED

Any interruption of the protective conductor inside or outside the instrument will make the

instrument dangerous. Intentional interruption is prohibited.

Connections

Front Panel Connections

Appliance Connector

The load under test should be plugged into the front panel appliance connector. Power to the

connector is supplied from the fixed LOAD POWER cable via an internal 20A fuse and a relay

which is controlled by the LOAD switch. If the LOAD switch is in the OFF position, or if there is no

instrument power (e.g. the POWER switch is OFF) then the load power supply is disconnected

from the appliance socket.

A wide choice of national appliance connectors is available but the connector is factory fitted and

cannot be changed by the user. The maximum load current that can be supplied is the rating of

the connector, or 16Arms, whichever is lower.

Voltage and Current Monitor

The Voltage Monitor and Current Monitor BNC sockets output reconstructed, scaled versions of

the load power voltage and current waveforms referenced to instrument ground, permitting direct

connection to other instruments such as an oscilloscope. The output voltage is approximately

2.5V pk-pk for a full-scale signal on any current or voltage range.

Rear Panel Connections

Instrument Power and Load Power

The IEC inlet supplies power for the instrument only; the fixed lead supplies the load power to the

front panel appliance connector. Refer to the Installation section.

USB

The USB interface is intended for communication with a PC running the HA-PC Link Plus

software. See software installation section for information about device driver requirements.

RS232

The RS232 interface should be connected to a standard PC port using a fully wired 1-1 male-

female cable without any crossover connections. It may also be used with a serial printer.

The 9-pin female D-connector has the following pin-out:

Name

Direction

Description

DCD

Passively asserted (+10V through 10k)

TXD

Transmitted data to computer

RXD

Received data from computer

DTR

Computer can receive

GND

Signal ground

DSR

Passively asserted (+10V through 10k)

RTS

( I )

Assumed asserted

CTS

Computer may send

No connection

The signal ground is connected to instrument ground. The Baud rate is fixed at 115,200.

Printer

25-way female D-connector configured as a standard parallel (Centronics) printer port. Connect

directly to a suitable printer using a standard shielded cable.

Initial Operation

This section is a general introduction to the organisation of the instrument and is intended to be

read before using it for the first time. It is important to recognise that compliance quality

measurements cannot be taken by relying on the instrument defaults. A full understanding of the

various configuration options must be gained by studying the detailed descriptions of each

function which follow in the sections of this manual below, starting with Power Meter.

In this manual front panel keys and connectors are shown in capitals, e.g. METER, VOLTAGE

MONITOR; all soft-key labels, messages and data values displayed on the LCD are shown in a

different type font, e.g. Setup Range, Load Declared Class A.

Switching On

With both the POWER and LOAD switches in the OFF position connect the INSTRUMENT

POWER lead to the standard AC supply and connect the LOAD POWER lead to a suitable low

distortion AC source as described in the Installation section.

Switch the POWER switch to ON to turn the instrument power on; the display will show the

Initialisation screen for a few seconds followed by the Select screen. A 20 second time-out is

started, with a count down shown on the display. If no key is pressed during this time out, or if the

Resume Operation soft-key (F5) is pressed, the instrument will continue operation using the

Test and Report parameters automatically stored at the last power−down; the parameter settings

stored are given in the table at the end of this chapter. The instrument will start up with the LCD

showing the Waveform Graph display. The display will show the load voltage waveform, which

will appear to be unstable for 4 to 5 seconds or more until the sampling clock synchronises

exactly with the incoming supply; the display will then show a single cycle of the voltage

waveform with the rising zero-crossing point at the left edge.

The second soft-key option on the Select screen is Restore Defaults; this continues

operation with all parameters defaulted to their original factory setting. The stored parameters

and their default settings are listed in the table at the end of this chapter.

The final soft-key option is Setup, which gives access to a further screen where the soft-keys

are Restart and Update Software. Restart returns the instrument to the Initialisation

screen. Update Software selects the mode in which the instrument’s firmware can be

updated from a PC via its RS232 or USB port; see the section of the Firmware Update chapter of

this manual for details.

If the load is now connected and the LOAD switch also turned to ON the load current waveform

will also show in the display; the instrument will auto-range to show the current waveform at the

best resolution achievable. Load power is always disconnected, even if the LOAD switch is ON,

when INSTRUMENT POWER is turned off.

Safety Note: Neither the POWER switch, nor the LOAD switch, fully disconnect their respective

AC supplies when switched to the OFF position. To fully disconnect from the AC supply unplug

the mains cords from the AC supply outlets; make sure that the means of disconnection are

readily accessible. Disconnect from the AC supplies when not in use.

Display Contrast

The contrast of the LCD may vary a little with changes of ambient temperature or viewing angle

but can be optimised for a particular environment by using the front panel contrast control. Insert

a small screwdriver or trimmer tool through the adjustment aperture marked LCD and rotate the

control for optimum contrast.

Keyboard

The keys on the front panel can be considered in the following groups:

•The five keys beneath the LCD. When the green VIEW lamp is lit these are used to directly

call each of the five main display views (METER for Power Meter, WAVE for Waveform Graph,

etc.). In addition, when the set-up screen for each of these views is displayed (by pressing

the SET-UP / VIEW key to light the red SET-UP lamp) they become 'soft-keys' which take the

functions shown immediately above them in boxes on the LCD.

•The four cursor keys marked andare used to move the edit zone (shown as an

outline box) around the editable fields of a set-up display. For each position of the edit zone

the keys below the display have the functions shown immediately above them in boxes on the

LCD; the functions change as the edit zone is moved which is why they are called 'soft' keys.

The cursor keys auto-repeat when held down.

•Numeric keys permit direct entry of values in certain set-up displays. ENTER confirms a

numeric entry and CANCEL terminates the entry without changing the parameter to the new

value.

•START TEST and STOP TEST have specific functions determined by the type of test selected

on the Test Control set-up display; full details are given in the Test Control section.

•The LOCAL key switches the instrument between remote and local (keyboard) control.

Stored Settings and their Factory Defaults

The following parameters have their present setting stored at power−down; these are recalled at

power−up if Resume Operation is selected. If Restore Defaults is selected instead, the

settings are those shown in the Defaults Setting column.

Parameter

Default Setting

Nominal Voltage and tolerance

230V ± 2%

Nominal Frequency and tolerance

50Hz ± 0.5%

Test Duration

Standard value for each mode.

Assessment inset

1.00

Operating Mode

EN61000-3-2:2014 Harmonics

Load Classification

Class A

Class C Limit basis, current and PF

Automatic (maximum fundamental current)

Class D Limit basis and power

Automatic (maximum power)

Class A, B or D minimum power

75W

Class D −A cross−over power (1995)

600W

Flicker sensing method

Voltage

Simulated Flicker Reference Impedance

0.4 + j 0.25 

dmax limit

4 %

tmax limit

* < 500 ms above 3.3%

dc limit

* 3.3 %

Steady State Definition

* > 1000 ms within ±0.2%

Switching sequence On and Off time

1000 cycles

Switching sequence On and Off phase

0 degrees

Left Margin (of Report)

5 characters

Report No.

* These values apply to EN 61000-3-3:2013 and differ from earlier issues.

Note that the Report’s Header, Title and Footer text is not restored to the original form by the

Restore Defaults choice; the text can only be changed by entering new characters.

Power Meter View

With the green VIEW lamp lit, press the METER key to display the Power Meter view.

The Power Meter view gives a continuously updated display of the major parameters of the

supply voltage and load current, together with an instantaneous summary of whether the supply

and load meet the limits of the harmonics standard.

The Supply Voltage group shows the Vrms and frequency of the load power supply,

together with its total harmonic distortion (THD), peak voltage (Vpk), the phase of the peak with

respect to the zero-crossing point and the calculated crest factor (Vpk/Vrms).

For compliance quality measurements, the load power supply must meet the following

requirements:

Harmonics (max % of fundamental) 0.9% : 3rd

0.4% : 5th

0.3% : 7th

0.2% : 9th

0.1% : even 2nd –10th

0.1% : all 11th –40th

Voltage 230 Vrms ± 2%

Frequency 50Hz ± 0.5%

Crest Factor (Vpk/Vrms) Between 1.40 and 1.42

Phase of Vpk Between 87° and 93° after zero crossing

All the above parameters are continuously monitored. All supply parameters are compared

against the limits and a pass or fail indication is given in the Harmonic Summary section of the

display.

The Load Power group shows the true power (Watts), apparent power (V.A) and power factor

(W/V.A). The maximum value of the true power is also shown.

The Load Current group shows the rms and peak load currents, together with the total

harmonic distortion (THD), the phase of the current peak, the calculated crest factor (Ipk / Irms)

and the total harmonic current (this is the rms sum of all the harmonics between 2 and 40 and

can be used to find a worst case operating condition of the load under test). When testing

harmonics for a Class C equipment the total harmonics display is replaced by the value of the

fundamental current

The Harmonic Summary group gives a simple overview of the supply and load harmonic

status. It states whether the supply passes or fails the specified requirements; compliance quality

measurements can obviously only be made with a supply that meets the harmonics, voltage,

frequency, crest factor and phase requirements described earlier. It also states the load class as

declared by the user and any power related exclusions detected by the analyser; refer to the Test

Control section. Lastly the display states whether the load current passes or fails the harmonics

limits of the Class shown.

When the instrument is operated in Inrush or Flicker mode the region at the bottom of the screen

is used to display a summary of those measurements instead of the Harmonic Summary. In

Flicker mode two further display pages are available: one showing Voltage Variations and the

second Flicker Results. For full details, see the relevant chapters in this manual.

Power Meter Set-up

With the Power Meter view displayed, pressing SET-UP shows the Power Meter set-up screen,

which gives access to the Setup Range soft-key. In Flicker mode, it also gives access to the

Flicker and Voltage Variations result pages. See the Flicker Meter chapter for details.

Set-up Range

Pressing the Setup Range soft-key (on either the Meter or Waveform Graph views) changes

the display to a graphical view of the current waveform with three further soft-keys: Up, Down

and Lock Range. Pressing any of these turns off auto-ranging; the Lock Range key keeps

the present measurement range, while the Up and Down keys change the range in ×2 and ÷2

steps respectively. The scaling of the waveform display changes to reflect the peak capability of

the new range and the maximum current is shown in the bottom left-hand corner of the display;

for example, 1500mA peak means that the top of the display represents +1500mA and the

bottom represents –1500mA with respect to the centre zero line.

The range can be set from 24mA peak to 400A peak in 2:1 steps. The waveform display on this

set-up screen is always updated every cycle, regardless of the mode set up for the Waveform

Graph view.

Important Note: Totake compliance quality measurements the range must not change during

the test. The user must select a range that will accommodate the highest waveform peak that will

be encountered during the load’s operating cycle. It is therefore recommended that a preliminary

assessment of the load should be made, with the instrument in auto-range mode, to determine

the highest peak current operating condition. The instrument should then be locked on this range

to ensure that harmonics measurements are correct and that the derived values (Average, Max

Hold and Min Hold etc.) are meaningful.

If too low a range is chosen, no damage will be done, but all the measurement results will be

invalid and the message Overload will show in the status line at the top of the Meter View display.

It is more important to maintain adequate ‘headroom’ for the measurement, i.e. to avoid overload,

than it is to maximise the vertical resolution on the Waveform Graph view; measurement

accuracy is maintained even when the vertical scaling of the display is well below optimum.

Once the range is locked, the Lock Range soft-key label becomes Auto Range; pressing

this key releases the lock and allows the instrument to auto-range on the present waveform.

Several other soft-keys 'toggle' between alternate choices in this way; it is only necessary to

remember that at any time the soft-key box shows what will happen when the key is pressed.

Having set the range (or selected auto-range), the previous view can be recalled by pressing the

VIEW key.

Auto-ranging is only available in Harmonics operating mode (see the Test Control section). Note

that auto-ranging is disabled while the LOAD switch is OFF to prevent the instrument auto-

ranging to the most sensitive range when there is no load current. At switch-on the default range

is 3A peak if the LOAD switch is OFF; at other times, switching the LOAD to OFF locks the range

at the setting currently in use.

In Flicker mode with voltage sensing, the current range can be manually changed, but should be

left at a setting that avoids overload at any time during the test (otherwise the test will be

needlessly aborted). When the current sensing method is selected, the range is fixed to suit the

requirements of the reference impedance calculations and cannot be changed.

On selecting Peak Inrush mode, the highest current range is initially set, but it can be manually

changed as required.

The Voltage range is determined by the Nominal Voltage value which must be declared on the

Test Control set-up menu to match the actual supply voltage.

Waveform Graph View

The Waveform Graph display (which is the default display at instrument switch on) can be

selected by pressing the WAVE key whenever the green VIEW lamp is lit. The default format of

the display is a full-screen view of both the voltage and current waveforms. The format of the

display can be changed in various ways as described in the Waveform Graph Set-up section

below.

At the top of the display the scaling for both voltage and current are given. There are 8 divisions

vertically, thus 100mA/div is the scaling shown if the ± 400mA peak range has been selected

on the set-up screen. Note that although the hardware ranges of the instrument are in a precise

2:1 ratio, the scaling of the graph display is adjusted slightly to give convenient round number

values per division. In auto-range mode (the default condition) the most sensitive range that

gives an in-range display is automatically selected. To avoid excessive range changes when the

measurement is near a range boundary the instrument auto-ranges up at full-scale and auto-

ranges down at about 0.44 times full-scale.

The voltage display has two ranges only: 100V/div, for nominal 230V supplies, and 50V/div for

nominal 115V supplies; the voltage range is set from the value of the nominal voltage which must

be declared on the Test Control set-up display.

The X-axis of the single cycle display is divided into 6 divisions, each representing 60° of phase.

The rising zero-crossing point of the single voltage waveform cycle displayed is positioned at the

left edge of the display for the default selection of voltage as the Trigger Source; this will change

if alternative Trigger Sources are selected, see Trigger Source section.

The X-axis is marked every 180º of the 2 cycle display and every cycle of the 4 and 10 cycle

displays.

When measuring low power lighting equipment <25 Watts to the Class C rules specifying

waveform phase angle requirements, the bottom line of this screen reports the phase angles of

the start of conduction, the last current peak and the end of conduction. There are also two

graphical markers (short vertical lines above and below the centre line) showing the assessed

position of the last current peak in each half cycle.

Waveform Graph Set-up

With the Waveform Graph view displayed, pressing SET-UP shows the Waveform Graph set-up

screen.

With the exception of the Setup Range key, the functions of the soft-keys change as the edit

zone is moved through the editable fields of the display using the keys; each field is

described below. Pressing the VIEW key returns the display to the Waveform Graph view.

Set-up Range

Pressing the Setup Range soft-key (on either the Meter or Waveform Graph views) changes

the display to a graphical view of the current waveform with three further soft-keys: Up, Down

and Lock Range. Pressing any of these turns off auto-ranging; the Lock Range key keeps

the present measurement range, while the Up and Down keys change the range in x2 and ÷2

steps respectively. The scaling of the waveform display changes to reflect the peak capability of

the new range and the maximum current is shown in the bottom left-hand corner of the display;

for example, 1500mA peak means that the top of the display represents +1500mA and the

bottom represents –1500mA with respect to the centre zero line. The range can be set from

24mA peak to 400A peak in 2:1 steps. The waveform display on this set-up screen is always

updated every cycle, regardless of the mode set up for the Waveform Graph view.

Important Note: Totake compliance quality measurements the range must not change during

the test. The user must select a range that will accommodate the highest waveform peak that will

be encountered during the load’s operating cycle. It is therefore recommended that a preliminary

assessment of the load should be made, with the instrument in auto-range mode, to determine

the highest peak current operating condition. The instrument should then be locked on this range

to ensure that harmonics measurements are correct and that the derived values (Average, Max

Hold and Min Hold etc.) are meaningful.

If too low a range is chosen, no damage will be done but all the measurement results will be

invalid and the message Overload will show in the status line at the top of the Meter View display.

It is more important to maintain adequate ‘headroom’ for the measurement, i.e. to avoid overload,

than it is to maximise the vertical resolution on the Waveform Graph view; measurement

accuracy is maintained even when the vertical scaling of the display is well below optimum.