Metrix MX 409 User manual

Megohmmeter
EN - User’s manual
MX 409

2
WARNING, risk of DANGER! The operator must refer to these instructions whenever this danger symbol appears.
Information or useful tip. Earth. Battery. Fusible.
The voltage on the terminals must not exceed 700V. Equipment protected by double insulation.
The product is declared recyclable following an analysis of the life cycle in accordance with standard ISO 14040.
Chauvin Arnoux has adopted an Eco-Design approach in order to design this appliance. Analysis of the complete
󰀨-
ance exceeds regulation requirements with respect to recycling and reuse.
The CE marking indicates compliance with the European Low Voltage Directive (2014/35/EU), Electromagnetic
Compatibility Directive (2014/30/EU), and Restriction of Hazardous Substances Directive (RoHS, 2011/65/EU and
2015/863/EU).
The rubbish bin with a line through it indicates that, in the European Union, the product must undergo selective
disposal in compliance with Directive WEEE 2012/19/EU. This equipment must not be treated as household waste.
Denition of measurement categories
Measurement category IV corresponds to measurements taken at the source of low-voltage installations.
Example: power feeders, counters and protection devices.
Measurement category III corresponds to measurements on building installations.

Measurement category II corresponds to measurements taken on circuits directly connected to low-voltage installations.
Example: power supply to electro-domestic devices and portable tools.
PRECAUTIONS FOR USE
This instrument is compliant with safety standard IEC/EN 61010-2-034 or BS EN 61010-2-034 and the leads are compliant with
IEC/EN 61010-031 or BS EN 61010-031, for voltages up to 600 V in category IV.
Do not use the instrument for measurements on circuits that are not in measurement categories II, III, or IV or that might be con-
nected inadvertently to circuits that are not in measurement categories II, III, or IV.
The operator and/or the responsible authority must carefully read and clearly understand the various precautions to be taken
in use. Sound knowledge and a keen awareness of electrical hazards are essential when using this instrument.
 
Do not use the instrument on networks of which the voltage or category exceeds those mentioned.
Do not use the instrument if it seems to be damaged, incomplete, or poorly closed.
Before each use, check the condition of the insulation on the leads, housing, and accessories. Any item of which the insulation
is deteriorated (even partially) must be set aside for repair or scrapping.
Before using your instrument, check that it is perfectly dry. If it is wet, it must be thoroughly dried before it can be connected or
used.
Use only the leads and accessories supplied. The use of leads (or accessories) of a lower voltage or category limits the voltage
or category of the combined instrument and leads (or accessories) to that of the leads (or accessories).
Use personal protection equipment systematically.
 
All troubleshooting and metrological checks must be performed by competent and accredited personnel.
Thank you for purchasing a megohmmeter MX 409.
For best results from your instrument:
read these operating instructions carefully,
comply with the precautions for use.
770 V

3
CONTENTS
1. FIRST START-UP.................................................................................................................................................................4
1.1. Unpacking....................................................................................................................................................................4
1.2. Accessories and spares...............................................................................................................................................4
1.3. Inserting the batteries ..................................................................................................................................................5
1.4. Using the protective sheath .........................................................................................................................................6
2. PRESENTATION OF THE INSTRUMENT..........................................................................................................................7
2.1. MX 409 ........................................................................................................................................................................7
2.2. Functions ....................................................................................................................................................................8
2.3. Display.........................................................................................................................................................................8
2.4. Keys and button...........................................................................................................................................................9
3. USE......................................................................................................................................................................................10
3.1. Checking the operation of the instrument..................................................................................................................10
3.2. Voltage measurement................................................................................................................................................10
3.3. Insulation resistance measurement...........................................................................................................................12
3.4. Continuity measurement............................................................................................................................................15
3.5. Resistance measurement..........................................................................................................................................18
3.6. HOLD function ...........................................................................................................................................................19
3.7. Backlighting ...............................................................................................................................................................19
3.8. SET-UP......................................................................................................................................................................20
3.9. Alarm function............................................................................................................................................................21
3.10. Programmed duration..............................................................................................................................................21
3.11. Automatic stop .........................................................................................................................................................22
4. TECHNICAL CHARACTERISTICS ..................................................................................................................................23
4.1. General reference conditions ....................................................................................................................................23
4.2. Electrical characteristics ............................................................................................................................................23
4.3. Variations in the range of use ....................................................................................................................................25
4.4. Intrinsic uncertainty and operating uncertainty ..........................................................................................................26
4.5. Power supply .............................................................................................................................................................26
4.6. Environmental conditions ..........................................................................................................................................27
4.7. Mechanical characteristics .......................................................................................................................................27
4.8. Compliance with international standards...................................................................................................................27
4.9. Electromagnetic compatibility (CEM).........................................................................................................................27
5. MAINTENANCE..................................................................................................................................................................28
5.1. Cleaning ....................................................................................................................................................................28
5.2. Replacing the batteries..............................................................................................................................................28
5.3. Replacing the fuse.....................................................................................................................................................28
5.4. Calibrating the instrument..........................................................................................................................................29
6. WARRANTY........................................................................................................................................................................32

4
1. FIRST START-UP
1.1. UNPACKING
1One MX 409.
2Two straight/right-angle safety leads (red and black).
3One red crocodile clip.
4One black test probe.
5
6Six LR6 or AA batteries.
7One carrying case.
8One multilingual safety data sheet.
9One multilingual getting started guide
10 
1.2. ACCESSORIES AND SPARES
For the accessories and spares, consult our web site:
www.chauvin-arnoux.com
➀
➅
➄
➃
➁➂
➆
➇➈➉
Ω
kΩ
190,rue Championnet
75876PARISCedex 18
FRANCE
ATTESTATION DE VERIFICATION
CHECKING ATTESTATION
Numéro de l'appareil :
Equipment number
Établien usine, ce document atteste que le produit ci-dessus a été vérifié et est conforme aux
conditionsd'acceptation définies dans nos procédures de fabrication et de contrôle.
Tousles moyensde mesure et d'essai utilisés pour vérifier cet appareil sont raccordés aux
étalonsnationaux et internationaux soit par l'intermédiaire d'un de nos laboratoires de métrologie
accréditésCOFRAC soit par un autre laboratoire accrédité.
Aprèssa mise en service, cet instrument doit être vérifié à intervalle régulier
auprèsd'un service de métrologie agréé.
Pourtout renseignement veuillez contacter notre service après vente et d'étalonnage.
Atthe time of manufacture, this document certifies that the above product have been verified and
complieswith acceptance conditions defined in our manufacturing and testing procedures.
Everytest or measuring equipment used to verify this instrument are related to national
andinternational standards through one of our laboratories of metrology certified by french COFRAC
equivalentto NAMAS in the UK or through another certified laboratory.
Afterbeing in use, this instrument must be recalibrated within regular intervals
byan approved metrology laboratory.Please contact our after sales and calibration department:
Serviceaprès vente et d'étalonnageTEL:[phone] FAX:[phone]
Aftersales and calibration departmente-mail:[e-mail]
WEB: www.manumesure.com
www.chauvin-arnoux.com
Vérifiépar :
Testedby
ATTESTATIONDE CONFORMITE
COMPLIANCE ATTESTATION
Nous certifions que ce produit a été fabriqué conformément aux spécifications
techniques de constuction applicables.
We certify that this product is manufactured in accordance with applicable
constructing specifications.
907009 119 - 02/03
Type/
Model
:
Désignation de l'instrument :
Instrument designation
Signature :
Signature
MX 409
MEGHOMMETER

5
1.3. INSERTING THE BATTERIES
Remove the protective sheath. Start by freeing the case from the top of the sheath.
Then withdraw the case from the sheath.
Turn the instrument over.
Use a screwdriver to unscrew the captive screw of the battery compartment cover, then remove the cover.
Insert the 6 batteries provided, with the polarities as shown.
Put the battery compartment cover back in place; make sure that it is completely and correctly closed.
Screw the captive screw back in.
Put the sheath back on the instrument, from the bottom.

6
1.4. USING THE PROTECTIVE SHEATH
You can place your instrument upright on its back stand.
To do this, pull the back stand down, to free it from its slot, then fold it and insert the end in the other slot.
The stand can also be used to hook the instrument on a door.

7
Ω
0
SET-UP
OFF
1000 V
500
V
700 V
max
Ω
FUSED
600 V CAT IV
V
kΩ
Ω
250 V
MX 409
MEGOHMMETER
MΩ
HOLD
Ω
P
0
V
kΩ
GΩ
MΩ
V%
mA
AC
+
DC
HOLD
NOISE
REL
2. PRESENTATION OF THE INSTRUMENT
2.1. MX 409
Seven-position switch.
Measurement terminals.
Backlit LCD display unit.
TEST button.
4 function keys.

8
2.2. FUNCTIONS
The megohmmeter MX 409 is a portable measuring instrument, with LCD display. Powered by batteries.
This instrument is used to check the safety of electrical installations. It can be used to test a new installation before it is powered
up, to check an existing installation, whether in operation or not, or to diagnose a malfunction in an installation.
The MX 409 is used to make:
voltage measurements,
insulation measurements at 250, 500, and 1000V,
continuity measurements,
resistance measurements.
The alarm function of the MX 409 makes it possible to check that the readings are OK rapidly, without looking at the display unit.
2.3. DISPLAY
Ω
P
0
V
kΩ
GΩ
MΩ
V%
mA
AC
+
DC
HOLD
NOISE
REL
1Indicates that the measurement is frozen.
2󰀨
3Indicates that the resistance of the leads is compensated in a continuity measurement.
4󰀨
5Indicates the condition of the batteries.
6Secondary display unit.
7Main display unit.
8Indicates whether the measurement is OK or not with respect to the alarm threshold.
9Indicates the presence of a hazardous voltage on the terminals
10 Indicates that the alarm is active in an insulation or DMR measurement.
11 Indicates that the beep is activated.
12 Indicates a spurious voltage in a continuity or resistance measurement.
➅
➀➁➂
➆
➄
➃
➇ ➈ 11
➉12

9
2.4. KEYS AND BUTTON
2.4.1. TEST BUTTON
Pressing the TEST button starts an insulation measurement.

In resistance measurement, it is used to enter the DMR mode and record the reference measurement. And also to exit from the
DMR mode.
2.4.2. FUNCTION KEYS
Key Function
HOLD

Pressing the key freezes or unfreezes the measurement.


In insulation measurement, pressing the key activates or deactivates the alarm.
In continuity measurement, pressing the key activates or deactivates the alarm beep.
In resistance measurement, pressing the key activates or deactivates the DMR alarm beep.
In voltage measurement, the key is pressed to choose between AC+DC measurement or DC only.

SET-UP
In insulation measurement, the TIMER key is used to select the and functions.
In insulation measurement, a long press on the key sets the alarm threshold corresponding to the test voltage.
In continuity measurement, a long press on the key serves to choose the alarm threshold.
In resistance measurement, a long press on the key lets you set the threshold in %.
Ω
0
󰀨
In continuity measurement, a long press lets you compensate the resistance of the measurement leads.

10
3. USE
3.1. CHECKING THE OPERATION OF THE INSTRUMENT
Before making any use of the instrument, check that it is operating correctly.
Make a voltage measurement on a known voltage. If the measurement is incorrect, do not use the instrument.
In continuity measurement, short-circuit the leads. The reading must be close to zero. If not, either the leads are defective or
the fuse must be replaced (see §5.3).
3.2. VOLTAGE MEASUREMENT
3.2.1. MAKING A MEASUREMENT
Set the switch to V. The instrument also makes voltage
measurements in the MΩ settings.
Using the leads, connect the device to be tested to the
terminals of the instrument.
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
V
AC
+
DC
The instrument displays the AC+DC voltage. If it is >30V, the symbol is displayed to warn the user that the voltage on the
terminals is hazardous.
To know the value of the DC component of the voltage, press the key.
V
AC
+
DC VDC

3.2.2. AC+DC MEASUREMENT
Why is it important to measure the AC+DC voltage?
100 V
-100 V
If the voltage is pure AC, the DC voltage reading is zero.
V = 0 V
V = 100 V
V = 100 V

11
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V

VDC
The AC+DC measurement yields better information as regards energy and electrical safety.
3.2.3. ERROR INDICATION
If the measurement departs from the measurement range, the instrument so reports by displaying OL.
3.2.4. BATTERY VOLTAGE
To check the battery voltage, press and hold the TEST key with the switch set to V.
V = 10 V
V = 0 V
V = 10 V
V = 100 V
V = 40 V
V = 140 V
10 V
If the voltage is pure DC, the AC voltage reading is zero.
If the voltage is mixed (AC plus DC), as in the example opposite, a DC voltage with a
ripple, the AC+DC measurement gives the true value; the AC measurement does not.
100 V

12
The measurement remains frozen until you press the HOLD key. The instrument then returns to voltage measure-
ment. You can also start another measurement immediately by a long press on the TEST button.

HOLD
3.3. INSULATION RESISTANCE MEASUREMENT
3.3.1. DESCRIPTION OF THE MEASUREMENT PRINCIPLE
The device generates a DC test voltage between the +and COM terminals. This voltage depends on the resistance to be meas-
ured: it is between UNand 1.25 UNwhen R ≥ RN= UN/ 1mA, and is lower otherwise. The device measures the voltage and current
present between the two terminals and from them deduces the value of R=V/I.
The COM terminal is the voltage reference point and the +terminal delivers a positive voltage.
3.3.2. MAKING A MEASUREMENT
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
Set the switch to one of the MΩ positions.
The test voltage you should choose depends on the voltage of the installation to be tested.
For example, for a network installation at 230 V, insulation measurements will be made
at 500 V.
Use the leads to connect the object to be tested to the terminals of the instrument.
The object to be tested must not be live.
V

Press the TEST button and keep it pressed until the measurement is stable. The symbol indicates that the instrument is gen-
erating a hazardous voltage.
When you release the TEST button, the measurement is frozen and the instrument displays HOLD. You can see the voltage falling,
which shows that the object tested is being discharged into the instrument. If the object tested is not capacitive, discharging is very
rapid. When the voltage falls below 30V, the symbol disappears from the display.
Do not disconnect the instrument while the symbol is still displayed.
MΩ
V
3.3.3. TIMER KEY
In insulation measurement, the following functions are available:
1st press This function is used to lock the TEST button so as not to have to keep it pressed during the
insulation measurement.
2nd press
This function is used to make a measurement having a programmed duration (see §3.10).
3rd press Return to the initial screen.

13

3.3.4. OPERATION OF THE TEST BUTTON
The TEST button is pressed to make an insulation measurement. The test voltage is generated for as long as the press is main-
tained. When the button is released, the measurement stops.
In the mode, simply long-press the TEST button to start the measurement, then long-press again to stop it; there is no need
to keep the button pressed. However, if you forget to stop the measurement, it will stop automatically after 40 minutes.
In the mode, simply long-press the TEST button to start the measurement; it stops automatically at the end of the programmed
duration.
3.3.5. ALARM

Before the insulation measurement, pressing the key activates the alarm.
The alarm threshold is displayed, along with the and
symbols.
Press the TEST key. If the measurement exceeds the
threshold, the symbol is displayed.
kΩ
VV
MΩ
The alarm thresholds can be programmed (see §3.9). There is one for each test voltage.
V
MΩ
On the other hand, if the measurement is below the threshold, the instrument emits a con-
tinuous beep, the backlighting lights red, and the symbol is displayed.

A second press on the key deactivates the alarm.

14
3.3.6. ERROR INDICATION
If the measurement departs from the measurement range, the instrument so reports by displaying LO (if the insulation re-
sistance is too low to allow generation of the voltage) or >4200MΩ (for a test voltage of 250 or 500V) or >11.00GΩ (for a test
voltage of 1000V).
If the object to be tested is at a hazardous voltage, the symbol is displayed, the instrument emits a pulsed beep, and
pressing the TEST button is impossible.
If the instrument fails to generate a voltage, check the fuse (see §5.3).

15
3.4. CONTINUITY MEASUREMENT
3.4.1. DESCRIPTION OF THE MEASUREMENT PRINCIPLE
The instrument generates a 200mA direct current between the +and COM terminals. It then measures the voltage present between
these two terminals and from it deduces the value of R = V/I.
3.4.2. MAKING A MEASUREMENT
To comply with the IEC 61557 standard, continuity measurements must be made with a positive current, then with a negative cur-
rent. The 2 measurements must then be averaged. The reversal of the current serves to compensate for any residual electromotive
forces and, more important, to check that the continuity is in fact duplex.
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
Ω
mA
Set the switch to Ω.
Use the leads to connect the object to be tested to the terminals of the instrument.
The object to be tested must not be live.
Ω
mA
R
To make sure that there is no voltage, make a voltage measurement before the continuity measurement.

Ω
mA
R
Ω
mA
Note the second value and calculate the average.
󰀨

16
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
Ω
mA
Ω
mA
Ω
mA
Ω
0

Ω
0
Press the key until the instrument beeps and displays the
Ω
0
symbol.

3.4.3. COMPENSATION OF THE MEASUREMENT LEADS
For best measurement accuracy, compensate the resistance of the measurement leads.
To do this, short-circuit the measurement leads. The instrument displays the resistance of the leads.
The leads are also compensated for resistance measurements.
󰀨

If you change the leads without redoing the compensation, the reading can become negative.
The backlighting then lights red and the symbol is displayed.
Carry out a compensation with the new leads.
3.4.4. ELIMINATING THE COMPENSATION OF THE MEASUREMENT LEADS
To eliminate the compensation of the leads, leave the leads open and press the key until the instrument beeps and the
Ω
0
symbol disappears.
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
Ω
mA

Ω
0
Ω
mA
Ω
0

17
3.4.5. ALARM
The alarm is always active in continuity measurement.

If the measurement is below the threshold, the symbol is displayed.
If the measurement exceeds the threshold, the backlighting lights red and the symbol is displayed.

To activate the audible alarm signal, press the key. The symbol is displayed and the beep is emitted
when the measurement is below the threshold. This lets you check that the continuity measurement is OK just
by listening, without looking at the display unit.
3.4.6. ERROR INDICATION
If the measurement departs from the measurement range, the instrument so reports by displaying >42.00Ω.
When the measurement current is <200mA, the measurement made is still correct but is no longer compliant with the standard.
If there is a voltage exceeding 0.4V on the object to be tested, the instrument displays NOISE.
If the object to be tested is at a hazardous voltage, >30V, the symbol is displayed and the instrument emits a pulsed beep.

18
3.5. RESISTANCE MEASUREMENT
3.5.1. DESCRIPTION OF THE MEASUREMENT PRINCIPLE
The device generates a DC voltage between the +and COM terminals. It then measures the voltage present between these two
terminals and from it deduces the value of R = V/I.
3.5.2. MAKING A MEASUREMENT
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V

Use the leads to connect the object to be tested to the terminals of the instrument.
The object to be tested must not be live.
Ω
R
Ω
To make sure that there is no voltage, you can make a voltage measurement before the continuity measurement.
Otherwise, the instrument will report the presence of a voltage if there is one.
If the leads have been compensated for continuity, this compensation will be used in resistance measurements..
3.5.3. DMR MODE
󰀨
all the resistances of a given installation are the same to within a few percent (generally 5%).
Start by setting the threshold in % (see §3.9).
 TEST button to record it. This will be the reference measurement.
Ω

Ω
%
REL

19
󰀨
󰀨
3.7. BACKLIGHTING

HOLD
Pressing the HOLD key freezes the display of the measurement.
This can be done in all functions.
To unfreeze the display, press the HOLD key again.

Ω
0
Pressing the key switches on the backlighting of the display unit.
󰀨 󰀨
󰀨
Ω
%
REL
3.5.4. ERROR INDICATION
If the measurement departs from the measurement range, the instrument so reports by displaying >420.0kΩ.
If there is a voltage of more than 0.4V on the object to be tested, the instrument displays NOISE.
If the object to be tested is at a hazardous voltage, >30V, the symbol is displayed and the instrument emits a pulsed beep.
3.6. HOLD FUNCTION
Ω
%
REL
󰀨
symbol is displayed.
󰀨
backlighting lights red and the symbol is displayed.

Pressing the 󰀨-
uous beep. This lets you check all of the resistances without looking at the display unit.

To exit from the DMR function, press the TEST button.

20
3.8. SET-UP
To go to the set-up of the instrument, press the TIMER key while turning the switch from OFF to any other setting. When you hear
the beep, release the TIMER key.

SET-UP
+
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
Then use the and keys to scroll and modify the parameters.
The beep is active.
On changes to OFF.
The next time the instrument is switched on, the alarm beep will be deactivated.
1st press on 
P
󰀨
This means that after 10 minutes with no sign of the user's presence, the instru-
ment switches to standby. Press the TEST button to wake the instrument.
󰀨OFF changes to On.
󰀨
P
symbol will be displayed.
2nd press on 
󰀨
󰀨
OFF changes to On.
󰀨-
lighting will be deactivated.
3rd press on Display of the version of the instrument's embedded software.
4th press on 
󰀨OFF.
All of the changes will be applied the next time the instrument is switched on.