Chauvin Arnoux C.A 6549 User manual

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■■
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■MÉGOHMMÈTRES
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■MEGOHMMETERS
C.A 6549
FRANCAIS
E N G L I S H
Mode d'Emploi
User's manual

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Meaning of symbol
!
CAUTION ! Refer to the user manual before using the instrument.
Failure to follow or carry out the instructions in this User Manual preceded by this symbol
may result in personal injury or damage to the instrument and the installations.
Meaning of symbol
This instrument is protected by double or reinforced insulation. It does not need to be
grounded for electrical safety.
Meaning of symbol
CAUTION ! Risk of electric shock.
The voltages of the parts identified by this symbol may be ≥120VDC. For safety reasons,
this symbol lights on the display unit as soon as a voltage is generated.
Thank you for purchasing this C.A 6549 megohmmeter and for your confidence.
For the best possible service from your instrument:
- read this User Manual carefully,
- comply with the precautions for use.
!
PRECAUTIONS FOR USE
!
■Comply with the conditions of use : temperature, humidity, altitude, degree of pollution and place of
use.
■This instrument may be used directly on installations of which the operating voltage does not exceed
1000V with respect to ground (measurement category III), or on circuits by-passing the network and
protected, or on circuits not by-passing the network (measurement category I).In the latter case, the
operating voltage must not exceed 2500V, with impulse voltages limited to 2.5kV (cf.NF EN 61010
ed.2 of 2001).
■Use only the accessories delivered with the instrument, compliant with safety standards (NF EN
61010-2-031).
■Use a fuse having the appropriate rating and type (see § 8.1.2); failure to do so may damage the
instrument and void the warranty.
■Set the switch to OFF when the instrument is not in use.
■Check that none of the terminals is connected and that the switch is set to OFF before opening the
instrument.
■Repairs and metrological verifications must be carried out by approved, qualified personnel.

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CONTENTS
1. PRESENTATION ............................................................................................................................ 50
1.1. The megohmmeter ............................................................................................................... 50
1.2. Accessories ......................................................................................................................... 50
2. DESCRIPTION ............................................................................................................................... 51
2.1. Housing / Front panel / Keys ................................................................................................ 51
2.2. Display ................................................................................................................................. 53
3. MEASUREMENT FUNCTION ........................................................................................................ 54
3.1. AC / DC voltage ................................................................................................................... 54
3.2. Insulation measurement ....................................................................................................... 54
3.3. Capacitance measurement .................................................................................................. 56
3.4. Residual current measurement ............................................................................................ 56
4. SPECIAL FUNCTIONS .................................................................................................................. 56
4.1. MODE/PRINT key ................................................................................................................ 56
4.2. DISPLAY/GRAPH key ......................................................................................................... 60
4.3. 3/ T° key ............................................................................................................................ 68
4.4. 6/ SMOOTH key ................................................................................................................ 69
4.5. SET-UP function (instrument configuration) ......................................................................... 69
4.6. List of coded errors .............................................................................................................. 75
5. PROCEDURE ................................................................................................................................ 75
5.1. Course of measurements ..................................................................................................... 75
5.2. Measurement in Voltage Step mode ..................................................................................... 77
6. MEMORY / RS 232 ......................................................................................................................... 78
6.1 RS 232 characteristics ......................................................................................................... 78
6.2 Recableing / plyback of memory (MEM/MR) ........................................................................ 79
6.2 Printing measured values (PRINT key) ................................................................................ 80
7. SPECIFICATIONS .......................................................................................................................... 85
7.1 Reference conditions ........................................................................................................... 85
7.2 Characteristics per function ................................................................................................. 86
7.3 Power supply ....................................................................................................................... 89
7.4 Environmental conditions ..................................................................................................... 90
7.5 Construction specifications .................................................................................................. 90
7.6 Compliance with international standards .............................................................................. 90
7.7 Variations with in domain of use ........................................................................................... 91
8. MAINTENANCE ............................................................................................................................. 91
8.1 Servicing .............................................................................................................................. 91
8.2 Metrological verification........................................................................................................ 92
9. GUARANTEE ................................................................................................................................. 92
10.TO ORDER .................................................................................................................................... 92

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1. PRESENTATION
1.1. C.A 6549 MEGOHMMETER
The C.A 6549 megohmmeter is a top-of-line measuring instrument, portable, in a rugged construction-
site housing with cover, with a graphic screen, operating from battery or line power.
Its main functions are:
§automatic detection and measurement of voltage / frequency / input current,
§quantitativeandqualitative insulation measurement:
- measurement at 500/ 1000/ 2500/ 5000V DC or other test voltage between 40 and 5100 V DC
(“adjustablevoltage”),
- measurement in voltage step mode (the applied voltage increases in steps),
- automatic calculation of DAR/PI and DD (dielectric discharge index) quality ratios,
- automatic calculation of measurement result referred to a reference temperature.
§automaticcapacitancemeasurement,
§automatic measurement of residual current.
This megohmmeter helps ensure the safety of electrical installations and equipment.
Its operation is controlled by microprocessor for the acquisition, processing, and display of measurements
and the storage and printing of results.
It has many advantages, among them:
- digital filtering of insulation measurements,
- automaticvoltagemeasurement,
- automatic detection of external AC or DC voltages on the terminals, before or during insulation
measurements, disabling or stopping the measurements when measurement accuracy is no longer
guaranteed,
- threshold programming to trigger audible alarms,
- timer for measurement time checks,
- protection of the instrument by fuse, with detection of defective fuses,
- operator safety by automatic discharge of residual high voltage on the equipment tested,
- automatic shutdown of the instrument to save battery power
- battery charge indication,
- large backlit graphic display unit that is very easy for the user to read,
- Memory (128 KB), real time clock, and serial interface
- PC control of the instrument (using the optional DataViewer Pro software)
- Printing in RS 232 or Centronics mode.
1.2. ACCESSORIES
§Measuring cables
The megohmmeter is delivered with 3 measuring cables as standard:
- 2 3m safety cables (red & black with rear pick up), with an HV plug for connection to the instrument and
an HV alligator clip for connection to the item tested
- 2 blue cables (3m and 0.3m with rear pick up) to measure high insulation values (cf. § 5.1).
Optionally, you can order the same cables in lengths of 8m and 15m, and also simplified cables (the
crocodile clip is replaced by a 4mm banana jack in which standard crocodile clips or contact pins can be
connected).

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§DataViewer Pro PC software
This is used to:
- recover stored data (results, graphs, etc.)
- print personalized test protocols in accordance with user needs,
- create text files to be able to use spreadsheets (ExcelTM, etc.),
- configure and completely control the instrument via the RS 232 port.
The minimum recommended configuration is a PC with a 486DX100 processor.
§Serial printer (optional)
This compact printer can be used to print measurement results, whether stored or not, directly in the field.
§Serial-parallel adapter (optional)
The optional RS232/Centronics adapter converts the serial interface (RS232) into a parallel printer interface
(Centronics), making it possible to print all measurements directly on A4-format office printers, without
using a personal computer.
2. DESCRIPTION
2.1. HOUSING
View of the front panel of the instrument
2.1.1. FRONT PANEL OFTHE C;A 6549

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- 3 4mm-dia. safety terminals identified as «+», «G», and «-»
- Access to the fuse that protects terminal “G”
- 8-way rotary switch:
§Off: switches instrument power off
§500 V-2 TΩ: insulation measurement at 500V up to 2 TΩ
§1000 V-4 TΩ: insulation measurement at 1000V up to 4 TΩ
§2500 V-10 TΩ: insulation measurement at 2500V up to 10 TΩ
§5000 V-10 TΩ: insulation measurement at 5000V up to 10 TΩ
§Adjust.50...5000V:insulationmeasurement with adjustabletest voltage (from 40Vto5100V:10V
steps from 40 to 1000V and 100V steps from 1000 to 5100V)
§Adjust. Step: insulation measurement with voltage step function (the test voltage varies in steps)
§SET-UP: adjustment of instrument configuration
- 1 yellow START / STOP key: beginning / end of measurement
- 8 elastomer keys each having a main function and a secondary function.
- 1 backlit graphic screen
- 1 socket for connection to line power (direct operation on line power and/or battery charging)
- 1 RS 232 serial INTERFACE male connector (9 pins) for connection to a PC or printer.
Note: The battery compartment is inside the housing.
2.1.2. KEYS
8 keys each having a main function and a secondary function :
2nd select the secondary function written in yellow italics below each key.
MODE Primary function :before insulation measurements, select the desired type of measurement.
PRINT Secondary function : immediate printing of measurement result(s) on a serial or parallel
printer.
DISPLAY Primary function : browse throught the various screens accessible before, during and
after the measurement.
GRAPH Secondary function : after a "timed run" measurement, display insulation resistance versus
measurement time.
4Primary function : select a parameter to be modified, to the right. At the end of the line, the
cursor jumps to the beginning of the line (all the way to the left).
Secondary function : activate / deactivate display backlighting.
3Primary function : select a parameter tobe modified, to the left
T° Secondary function :activate the calculation to refer the measurement value to the reference
temperature programmed in SET-UP.
5Primary function : in the various menus, select a function; otherwise, generally, increment
the flashing parameter on which the cursor is positioned. Pressing and holding the key
increases the rate of change of the parameter.
ALARM Secondary function : activate / deactivate the alarms programmed in the SET-UP menu.
6Primary function : in the various menus, select a function; otherwise, generally, decrement
the flashing parameter on which the cursor is positioned. Pressing and holding the key
increases the rate of change of the parameter.
SMOOTH Secondary function : enable / disable display smoothing in insulation measurement.

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MEM Fonction première : store measured values.
MR Fonction seconde : retrieve stored data (this function is dependent of the switch position),
except in the OFF and SET-UP positions.
2.2. DISPLAY
2.2.1 GRAPHIC DISPLAY UNIT
Thedisplay unitisa graphicdisplayunit witha resolution of320 x 240pixels. It hasbuilt-in backlighting that
can be activated or deactivated using the ✻ key.
The various screens that are accessible are presented and explained throughout this manual.
We explain below, however, the various symbols that may appear on the screen.
2.2.2 SYMBOLS
REMOTE Indicates that the instrument is controlled remotely via the interface.
In this mode, all of the keys and the rotary switch are inactive, except for shutdown of
the instrument (OFF position).
COM Flashes when data are transmitted to the serial interface.
Lit steadily if there is a problem in transmission.
2nd Indicates that the secondary function of a key will be used.
¿Indicates that the "programmed time test" mode was selected before the measurement
was started.
DAR Indicates that the "automatic calculation of Dielectric Absorption Ratio" mode was
selected before the measurement was started.
PI Indicates that the "automatic calculation of Polarization Index" mode was selected before
the measurement was started
DD Indicates that the "automatic calculation of Dielectric Discharge Index" mode was
selected before the measurement was started.
SMOOTH Smoothing of insulation measurement display.
ALARM Indicates that the alarm is activated. An audible alarm will be emitted if the value
measured is above the limit value defined in the SET-UP menu.
Indicates the battery charge condition (cf.§ 8.1.1.)
Voltage generated dangerous, U > 120VDC.
External voltage present, symbol activated following press on START key, if U > 25VRMS

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3. MEASUREMENT FUNCTIONS
3.1. AC / DC VOLTAGE
Turning the switch to an insulation position (position other than OFF or SET-UP) sets the instrument to
automatic AC / DC voltage measurement.
The voltage between the input terminals is measured at all times and indicated on the display unit:Input
Voltage.
Also, as soon as the switch is turned, the frequency and the residual DC current between the terminals of
the instrument are measured. The residual current is measured in order to evaluate its impact on the
insulation measurement to come.
The insulation measurements cannot be started if there is an excessively high external voltage on the
terminals.
Also, if an excessively high spurious voltage is detected during the measurement, the measurement is
automatically stopped : the symbol is displayed next to the measured external voltage (see § 3.2).
Switching between the AC and DC modes is automatics; in AC, RMS values are measured.
3.2. INSULATION MEASUREMENT
§When the switch is turned to an insulation position, one of the following displays appears :

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Case 1
You select an insulation measurement with a fixed /
standard test voltage, in manual mode.
Positions :
500V - 2TΩΩ
ΩΩ
Ω
1000V - 4TΩΩ
ΩΩ
Ω
2500V - 10TΩΩ
ΩΩ
Ω
5000V - 10TΩΩ
ΩΩ
Ω
Case 2
You select an insulation measurement with a test
voltage other than those proposed as standard.
Position :
Adjust.50V...5000V
You can choose from the 3 "adjusted" voltages
predefined in SET-UP using the 5and 6keys, or
define another voltage by selecting it with the 4
key and adjusting it with the 5and 6keys.
Case 3
You select an insulation measurement with a test
voltage that varies in steps :this is the "step function"
mode.
Position :
Adjust. Step
You can choose among the three step functions
(5and 6keys) you defined earlier in SET-UP.
§Pressing the START/STOP key immediately triggers the measurement.
An audible beep is emitted every 10 seconds to indicate that a measurement is in progress.
A number of special functions can be used during the measurement (cf. § 4.).
Importantremark:
These insulation measurements cannot be started if there is an excessively high external voltage on the
terminals.
§If, when the START key is pressed, the external voltage on the terminals of the instrument is
greater than the value U peak defined below, the insulation measurement is not triggered and an
audible alarm is emitted; the instrument then returns to automatic voltage measurement.

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U peak ≥dlSt x Un
where - Upeak : external voltage, peak or DC, on the terminals of the instrument.
- dlSt : coefficient that can be adjusted in SET-UP - 3% (defaut value), 10% or 20%.
- Un : test voltage selected for the insulation measurement.
§Similarly, if during the insulation measurements, an external voltage greater than the value U peak
defined below is detected, the measurement is stopped and the symbol appears next to the value of
the external voltage measured.
U peak ≥(dlSt + 1,05) x Un,
where - Upeak : external voltage, peak or DC, on the terminals of the instrument.
- dlSt : coefficient that can be adjusted in SET-UP - 3% (defaut value), 10% or 20%.
- Un : test voltage selected for the insulation measurement.
Note :
The dISt factor is adjusted to optimize the measurement build-up time.
If there is no spurious voltage, dISt can be adjusted to its minimum value to obtain the shortest possible
measurement build-up time.
If there is a large spurious voltage, dISt can be increased so that the measurement will not be interrupted
as soon as a negative alternation occurs during the generation of the test voltage;this amounts to optimizing
the measurement build-up time in the presence of a spurious voltage.
§Pressing the START/STOP key again stops the measurement
Ifthe “programmedtime test” mode(TimedRunorTimed Run +DD)was selected as measurement mode,
the measurement is stopped (without action on the START/STOP button) at the end of this time.
Similarly, if the DAR and PI modes are selected as measurement modes, the measurement is stopped
only after the time needed to calculate them (time defined in SET-UP).
A number of special functions can be used during the measurement (cf. § 4.).
3.3. CAPACITANCE MEASUREMENT
The capacitance measurement is performed automatically during the insulation measurement, and is
displayed after the measurement stops and the circuit has been discharged.
3.4. RESIDUAL CURRENT MEASUREMENT
The residual current circulating in the installation is measured automatically upon connection to the
installation, then during and after the insulation measurement.
4. SPECIAL FUNCTIONS
4.1. MODE / PRINT KEY
■The primary function of the MODE key is very important : it is used before the
measurement to define the course of the measurement.
This key is inactive in the "Adjust. Step" and SET-UP positions.
Pressing the MODE key gives access to the list of possible measurement modes. Select the mode
using the 5,6,4and 3arrows.