Gossen MetraWatt METRISO G1000A User manual

METRISOG1000A
Insulation and Resistance Measuring Instrument 3-349-675-03
3/9.14
Operating Instructions

2GMC-I Messtechnik GmbH
Overview of Included Features Scope of Delivery
1 Insulation and resistance measuring instrument
1 Factory calibration certificate
1 Set of batteries (8 pieces in battery holder)
1Carryingstrap
1 Alligator clip
1 KS17-4 cable set
1 Condensed operating instructions
1 CD ROM with the following content:
– Comprehensive operating instructions
(English and German)
– Data sheet
Battery Compartment Lid and Location of the Fuses
(housing bottom)
METRISO G1000A
Article number M542A
Measurements:
RINS U = 50, 100, 250, 500, 1000 V
3
RLO 0.17 ... 4  3
U 10 ... 1000 V 3
Display Functions:
Scale illumination
3
Limit value LED (green/red) for:
additional acoustic signal,
limit values per VDE 0100
RINS RLO
Caution LED
for dangerous contact voltage
– When switched off
– For active test voltage
3
FUSE LED
For blown fuse
3
Battery level display 3
Special Functions:
Discharge capacitive devices under test
3
Safety shutdown (UBatt < 8 V) 3
Features:
Measuring category
CAT II 1000 V / CAT III 600 V / CAT IV 300 V
3
Test resistor: 10 M 3
Factory calibration certificate 3
a b
Replacement Fuse
Fuse Link
Battery Compartment Lid

GMC-I Messtechnik GmbH 3
Inserting the Battery Holder (side view) Connections (housing top)
1Z550A accessory as option: test probe with START/STOP key and an additional
key for illuminating the measuring point, including shielded, plug-in connector
cable
Battery Holder
Battery Compartment Lid
Battery Holder
Contacts
Battery
Contact
Spring
User Interface
Compartment
Shielded
Cable
Test
Resistor
Test
Resistor
Test Pro be with
Control Keys 1
Connector with
Shielded Cable,
Option KS-C (Z541F)
(G500/G10 G500/G1000)
Measuring Connections
+COM
+ COM
10 M
GUARD SHIELD
Guard connection
see section 5.4

4GMC-I Messtechnik GmbH
User Interface
Red LED: limit value violated
Red LED:
– Interference voltage with device off
Function
Selector Switch
Guide for
Carrying Strap
Guide for
Carrying Strap
Green LED: limit value complied with
– Blinking indicates standby mode
Control Panel Keys
(see description on page 5)
Display Panel
(see description on page 5)
Refer to page 10 for a description of the LEDs.
– Test voltage active

GMC-I Messtechnik GmbH 5
Control Panel Keys – Adjusting Screw
aSTART: Starts insulation resistance measurement depending
on rotary selector switch setting (see measuring ranges ➀and
➁), or low-resistance measurement with automatic polarity
reversal (see low-resistance measuring range ➂).
Reactivates the instrument from the standby mode.
bCONTIN./ZERO *
Starts long-term measurement for insulation and low resis-
tance (low resistance: polarity in one direction only).
Each measurement takes up to 3 minutes; the instrument is
then switched to standby. Reactivates the instrument from the
standby mode.
cBat. TEST: Starts the battery test (see battery level display ➄
and section 3.1).
d10k-1T/100k-100M
Switches between measuring ranges for insulation resistance
measurement (see measuring ranges
➀ and ➁ , as well as sec-
tion 5.2).
Reactivates the instrument from the standby mode.
Mechanical Zero Point – Adjusting Screw (e)
If necessary, use the adjusting screw (e) to set the pointer to the
mechanical zero point (measuring range lower limit for all measur-
ing ranges, except battery level indicator) with the switch in the
OFF position.
Electrical Zero Point – ZERO Function (Roffset)
ZERO function (Roffset): for subtracting cable resistance from the
measurement results with the help of the CONTIN. and 10k-1T/
100k-100M keys (see section 7.3).
* the supplementary labelling „ZERO“ depends on the product series
Analog Display Symbols
1Insulation resistance measuring range: 10 k... 1 T
LED ➀ lights up orange: this measuring range is active
LED ➀ blinks orange: open cable ends (special case with
50 V test voltage: full-scale pointer deflection of 1 G)
2Insulation resistance measuring range: 100 k... 100 M
LED ➁ lights up orange: this measuring range is active
3Low-resistance measuring range: 0 ... 5 
LED ➃blinks orange if the range is exceeded
4Voltage measuring range: 0 ... 1000 V
LED ➃ lights up orange: low-resistance measurement is active
LED ➃lights up orange: voltage measurement is active
5Battery level indicator :
Left-hand range limit: batteries low or weakly charged
Right-hand range limit: batteries full or fully charged
6Fuse link and electronic fuse:
FUSE ZERO/FUSE ➅ blinks red: blown fuse
Voltage measurement is still possible.
– Funktion ZERO (Roffset):
LED ZERO/FUSE ➅ lights up red permanently after
offset blancing, see section 7.3.
a b c d
e
1
2
4
5
6 3
➀
➁
➃
➅

6GMC-I Messtechnik GmbH
Contents Page Contents Page
1 Applications ...............................................................................7
2 Safety Features and Precautions ..............................................8
3 Initial Start-Up ...........................................................................9
3.1 Battery Test .....................................................................................9
3.2 Installing or Replacing Batteries .....................................................9
4 General Operation ....................................................................10
4.1 Switching On, Monitoring and Switching Off ................................10
4.2 Analog Display ...............................................................................11
5 Insulation Resistance Measurement
– Riso/Rins Function ...............................................................12
5.1 Connection ....................................................................................12
5.2 Executing the Measurement .........................................................12
5.3 Ending the Measurement – Safe Discharging ...............................14
5.4 Measurements with the Guard Cable ............................................14
6 Measuring Direct, Alternating and
Pulsating Voltage – V Function ................................................15
7
Measuring Low-Resistance of up to 5 
– RLO Function ........................................................................16
7.1 Measurement with Automatic Polarity Reversal ...........................17
7.2 Measurement with Manual Polarity Reversal ................................17
7.3 Taking Measurement Cables and Extension Cables into Account (up
to 5 ) – ZERO Function (Roffset) .................................................18
8 Test Resistor for Insulation Measurement for Checking the
Insulation Measuring Instrument .............................................18
9 Technical Data ........................................................................19
10
List of Abbreviations and their Meanings ..................................... 23
11 Maintenance ........................................................................... 24
11.1 Battery and Rechargeable Battery Operation ................................24
11.2 Fuses .............................................................................................24
11.2.1Fuse Link – ZERO/FUSE LED ...................................................................... 24
11.2.2Electronic Fuse – ZERO/FUSE LED ............................................................. 25
11.3 Housing .........................................................................................25
12 Recalibration ........................................................................... 26
13 Appendix ................................................................................. 26
13.1 Sample Connection Layouts for Insulation Resistance Measurement 26
13.2 Attaching the Test Probe Holder to the Carrying Strap .................29
13.3 Technical Data for Measurement Cables
(scope of delivery: KS17-4 safety cable set) .................................30
13.4 Optional Accessories (not included) ..............................................31
14 Repair and Replacement Parts Service
Calibration Center* and Rental Instrument Service ...................... 31
15 Product Support ...................................................................... 32

GMC-I Messtechnik GmbH 7
1 Applications
These instruments fulfills all requirements of applicable European
and national EC directives. We confirm this with the CE mark. The
relevant declaration of conformity can be obtained from GMC-I
Messtechnik GmbH.
The METRISO G1000A insulation and resistance measuring instru-
ment allows for quick and efficient testing of protective measures
in accordance with DIN VDE 0100, ÖVE-EN 1 (Austria), SEV 1000
(Switzerland), and regulations specific to other countries as well.
The device is equipped with a microprocessor and complies with
IEC/EN 61557 / VDE 0413 regulations:
Part 1: General requirements
Part 2: Insulation resistance measuring instruments
Part 4: Instruments for measuring resistance at earthing con-
ductors, protective conductors and equipotential bonding
Part 10: Combined measuring equipment for testing, measuring
or monitoring protective measures
as well as requirements per VDE 0701-0702:
Repair, modification and testing of electrical devices
The test instrument is especially well suited for:
•Systemssetup
• Initial start-up
• Periodic testing
• Troubleshooting in electrical systems
The following measurements and tests can be performed with the
insulation measuring instruments:
• Insulation Resistance
• Low-resistance
• Voltage
The following can also be tested by using a shielded measure-
ment cable:
• Floor covering electrostatic discharge capability

8GMC-I Messtechnik GmbH
2 Safety Features and Precautions
The electronic measuring and test instrument is manufactured
and tested in accordance with safety regulations IEC/EN 61010-
1/VDE 0411-1 and EN 61557. When used for its intended pur-
pose, safety of the operator, as well as that of the instrument, is
assured.
Read the operating instructions thoroughly and carefully before
using your instrument. Follow all instructions contained therein.
The measuring and test instrument may not be placed into ser-
vice:
• If the battery compartment lid has been removed
• If external damage is apparent
• If connector cable or measuring adapters are damaged
• If the instrument no longer functions flawlessly
• After extraordinary stressing due to transport
• After a long period of storage under unfavorable conditions
(e.g. humidity, dust or extreme temperature)
Opening of Equipment / Repair
The equipment may be opened only by authorized service per-
sonnel to ensure the safe and correct operation of the equipment
and to keep the warranty valid.
Even original spare parts may be installed only by authorized ser-
vice personnel.
In case the equipment was opened by unauthorized personnel,
no warranty regarding personal safety, measurement accuracy,
conformity with applicable safety measures or any consequential
damage is granted by the manufacturer.
Meanings of Symbols on the Instrument
Warning concerning a point of danger
(attention, observe documentation!)
Protection class II device
CAT II / III Device assigned to measuring category
CAT II 1000 V / CAT III 600 V / CAT IV 300 V
EC mark of conformity
The device and included batteries may not be dis-
posed of with the trash. Further information regarding
the WEEE mark can be accessed on the Internet at
www.gossenmetrawatt.com by entering the search
term “WEEE”.
!

GMC-I Messtechnik GmbH 9
3 Initial Start-Up
3.1 Battery Test
A battery test should be conducted after inserting the batteries, or
if none of the measuring range LEDs lights up during insulation
resistance measurement. Press and hold the Bat. TEST key to this
end. Pointer deflection within the scale for the battery test indi-
cates the condition of the batteries with an average load amount-
ing to a test voltage of 1000 V. The rotary selector switch position
is not taken into consideration. The left-hand scale limit repre-
sents minimum required supply voltage, and the right-hand limit
represent maximum available supply power.
Note
If the pointer is only deflected into the minimum supply
power range, several measurements can still be executed
with test voltages of less than 1000 V, because the bat-
tery test is conducted with a load which amounts to a test
voltage of 1000 V.
The instrument does not function if the batteries have been
depleted excessively, and alarm indication does not work either.
3.2 Installing or Replacing Batteries
New batteries must be inserted for initial start-up, or if only mini-
mal supply power is indicated.
Attention!
!
Before opening the battery compartment (see page 5 for
location), disconnect the instrument from the measuring
circuit (mains) at all poles.
Eight 1.5 V size AA batteries in accordance with IEC LR 6 are
required for operation of the insulation measuring instrument. Use
new alkaline manganese batteries only.
Rechargeable NiCd or NiMH batteries may also be used. These
can only be recharged externally. We recommend rechargeable
NiMH batteries.
Always replace batteries in complete sets.
Dispose of batteries in an environmentally sound fashion.
ÐLoosen both slotted screws for the battery compartment lid
on the back, and remove the lid.
ÐRemove the battery holder and insert eight 1.5 V size AA bat-
teries with correct polarity in accordance with the symbols.
Attention!
!
Make sure that all of the batteries are inserted with correct
polarity. If just one battery is inserted with reversed polar-
ity, it will not be recognized by the instrument and may
result in leakage from the batteries.
Ð
Push the battery holder into the battery compartment such that
the battery holder’s contacts touch the contact springs at the
bottom of the battery compartment (see drawing on page 3).
If the battery holder is not inserted as specified, the instrument
cannot be supplied with power.
ÐReplace the battery compartment lid and retighten the
screws.
Attention!
!
The instrument may only be placed into service if the
battery compartment lid is securely fastened!

10 GMC-I Messtechnik GmbH
4 General Operation
The test leads are connected to the “+” and “COM” jacks.
When measuring electrostatic
discharge capacity for floor
coverings, the shielded cable
should also be connected to
the COM and SHIELD jacks (KS-C
accessory set, “cable set con-
sisting of measurement cable
and high-resistance measure-
ment cable for measurements
in the Grange” (see diagram). Be sure to observe color coding.
4.1 Switching On, Monitoring and Switching Off
The instrument is switched on as soon as the rotary switch is
turned to any position other than OFF.
If battery voltage falls below the allowable limit value (U < 8 V), the
instrument cannot be switched on, or it is immediately switched
off.
Measurement cannot be started in the resistance measuring
ranges in the event of interference voltage.
The instrument is switched to the standby mode after 3 minutes,
if neither the rotary switch nor any keys have been activated dur-
ing this time.
A brief acoustic signal is generated before the instrument
switches itself off automatically with the rotary switch in a position
other than OFF. Moreover, 6 brief acoustic signals indicate every
10 minutes that the device is still on standby. The device should
be switched off by setting the rotary selector switch to OFF in
order to save (rechargeable) batteries.
The instrument can be activated once again by pressing the START
key.
The instrument can be switched off manually by turning the rotary
switch to the OFF position.
For purposes of transport and maintenance, we recommend turn-
ing the rotary selector switch to the OFF position in order to avoid
switching the test instrument on inadvertently.
Start-Up Test
When the instrument is switched on, i.e. as soon as the rotary
switch is turned to any position other than OFF, all LEDs light up
briefly: limit, caution, blown fuse, insulation resistance measuring
ranges, voltage measurement and scale illumination.
Optical Indicators
1Function testing should be executed at regular intervals (see following section re-
garding testing the LEDs).
KS-C
(Z541F)
+
COM
SHIELD
GUARD
LED Status Function – Cause
Limit value indication
–Measuredinsulation resistance does not violate the limit
value.
– Measured low-resistance Rlo does not violate the limit
value.
Limit value indication
– Measured insulation resistance has fallen short of the limit
value.
– Measured low-resistance Rlo has exceeded the permissible
limit value.
Detection of interference voltage in the off state 1
If dangerous voltage of greater than 50 V is present at the measure-
ment inputs:
– Initialization of the insulation resistance and
low-resistance measurements is disabled.
– Presence of test voltage is indicated.
Limit
Green
Limit
Red
!
Red

GMC-I Messtechnik GmbH 11
Testing the LED which Indicates Detection of Interference Voltage
when Switched Off – OFF Switch Position
Ð Apply a voltage of greater than 50 V (+ and COM jacks).
ÐTurn the rotary switch to the V position.
ÐRead the voltage value at the analog display.
ÐTurn the rotary switch to the OFF position.
Test results: If applied voltage is unchanged and the LED which
indicates the detection of interference voltage lights up red, the
LED is OK. In this case, the LED reliably indicates interference
voltage even when the instrument is switched off. We recom-
mend executing this test at regular intervals.
Limit Values for Insulation and Low-Resistance Measurements
Limit LEDs for Insulation Resistance and Low-Resistance
Measuring Ranges
The Limit LED lights up green if the measured insulation resistance
value does not violate the limit value. The Limit LED lights up red, if
the measured insulation resistance value violates the limit value. If
the Limit LED does not light up at all, this means that the selected
test voltage value has not been reached. A battery test is advis-
able in this case.
4.2 Analog Display
Insulation Resistance Measuring Ranges
The logarithmic representation of the upper resistance scale
allows for quick recognition of the order of magnitude.
In order to achieve the required accuracy during protective mea-
sures testing, the 10k-1T/100k-100M key makes it possible to
switch to the expanded lower measuring range of 100 k
100 M.
The two orange LEDs, ➀and ➁, indicate which of the two resis-
tance measuring ranges is active at the moment.
Low-Resistance Measuring Range
LED ➃lights up orange to indicate that low-resistance measure-
ment is active. LED ➃blinks when the measuring range is
exceeded.
Voltage Measuring Ranges
The two lower scales are for voltage measurement and the bat-
tery test (see section 3.1). LED ➃lights up orange in order to indi-
cate that voltage measurement is active.
Measuring Range Overflow in the Resistance Measuring Ranges
The LED assigned to the respective measuring range, namely ➀,
➁or ➃blinks orange in the event of measuring range overflow.
Scale Illumination
Scale illumination is active for about 15 seconds after switching
the instrument on, after a measurement is started and after
changing measuring ranges.
Limit RISO / RINS 50 k@ UISO/UINS = 50 V
100 k@ UISO/UINS = 100 V
500 k@ UISO/UINS = 250 V
1M@ UISO/UINS = 500 V
1M@ UISO/UINS = 1000 V
Limit RLO 2 

12 GMC-I Messtechnik GmbH
5 Insulation Resistance Measurement
– Riso/Rins Function
5.1 Connection
Note
Checking the Measurement Cables
Before performing insulation measurement, the test
probes on the measurement cables should be short-cir-
cuited in order to assure that the instrument displays a
value very close to 0 (see section 7).
This makes it possible to detect interrupted measurement
cables, which simulate high insulation resistance.
ÐConnect the device under test to the +and COM jacks.
Sample connection layouts for insulation resistance measurement
are included in section 13.1.
Note
Insulation resistance can only be measured at voltage-
free objects. The measurement cannot be started until
the test probes are in contact with the device under test.
If line voltage or interference voltage of greater than 50 V
is applied to the measurement inputs, this is indicated by
means of a double acoustic signal. Insulation measure-
ment cannot be started as long as interference voltage is
present.
5.2 Executing the Measurement
Note: Condensation must be ruled out when performing measure-
ments at close to the freezing point.
ÐSelect the measuring function, as well as the desired test volt-
age depending on the device under test, with the rotary
switch, e.g. RiSO 100 V.
Attention!
!
Do not touch the instrument’s terminal contacts or the
conductive ends of the two test probes during insulation
resistance measurement!
If nothing has been connected to the terminal contacts, or if a
resistive load component has been connected for measurement,
your body would be exposed to a maximum short-circuit current.
The resulting electrical shock is not life endangering. However, the
noticeable shock may lead to injury (e.g. resulting from a startled
reaction etc.).
ÐStart an individual measurement by briefly pressing the START
key, or initiate continuous measurement by briefly pressing
the CONTIN./ZERO key.
ÐContact the measuring point with both test probes.
A double acoustic signal indicates that measurement has been
started.
The Caution! LED remains illuminated for as long as test voltage
is applied to the test probes.
LED ➀lights up to indicate that the upper measuring range of
10 k1Thas been complied with (default setting).
ÐWait until the pointer settles in. Depending on the device
under test, this may take anywhere from several seconds to
half a minute if, for example, large capacitors (long cables)
have to be charged.
ÐRead the measured value from the upper voltage scale ➀.
If the Limit LED lights up green, the insulation measurement is
valid and the limit value has not been violated.
If the limit value is fallen short of, the Limit LED lights up red.
!

GMC-I Messtechnik GmbH 13
Note
If the Limit LED does not light up at all, this means that the
selected test voltage value has not been reached. A battery
test is advisable in this case (see section 3.1 on page 9).
ÐSwitching to the Measuring Range with Higher Resolution
In order to perform measurement with the enhanced accuracy
required for protective measures testing, select the measuring
range with higher resolution, namely 100 k100 M, with
the help of the 10k–1T/100k–100M key immediately after the
measured value is displayed. LED ➁, which is assigned to this
measuring range, lights up.
ÐRead the measured value from the lower voltage scale ➁.
If the Limit LED lights up green, the insulation measurement is
valid and the limit value has not been violated. If the limit value is
fallen short of, the Limit LED lights up red.
After test voltage is switched off – Caution! LED goes out
(U > 50 V) – the pointer remains frozen in place for about 3 sec-
onds. When the Limit LED and the LED for measuring range ➁
both go out, the measurement has been completed and the
pointer returns to its neutral position.
Note
Three-Phase Systems
All conductors (L1, L2, L3 and N) must be tested against
PE!
Note
The instrument’s batteries are exposed to excessive
stress during insulation resistance measurement. For this
reason, it’s advisable to perform individual rather than
continuous measurements.
+
COM
+
COM
SHIELD GUARD
L1
L2
N
PE
L3
RBRE
RINS
Rx
0V!
!
RINS
RINS
1
2
➀
➁
!

14 GMC-I Messtechnik GmbH
Special Case: Capacitive Devices Under Test
Caution!
If measurement is performed at a capacitive object such
as a long cable, it becomes charged with up to approxi-
mately 1000 V (test voltage)! Touching such objects is life
endangering!
5.3 Ending the Measurement – Safe Discharging
Individual measurement: Measurement is ended automatically as
soon as the measured value has settled in.
Continuous measurement is ended by once again briefly pressing
the CONTIN./ZERO key.
When an insulation resistance measurement has been performed
on a capacitive object it’s automatically discharged by the instru-
ment. Contact between the object and the instrument must nev-
ertheless not be interrupted.
Do not disconnect until:
•TheCaution! LED (U > 50 V) is no longer illuminated.
As an alternative, the device under test can be discharged in a
controlled manner (due to touch hazard) by switching to V and
contacting the device under test until the Caution! LED is no
longer illuminated and the measuring movement indicates 0 V.
Do not reverse polarity while discharging, because internal surge
protection will otherwise be triggered.
5.4 Measurements with the Guard Cable
The measurement of very high resistances necessitates extremely
minimal measuring current and may be rendered problematic as a
result of influences such as electromagnetic fields, humidity or
surface pollution. An accurate test set-up is thus absolutely
essential.
A guard cable must be used for measurements within a range of
100 G(10 G) 1T, in order to prevent surface current from
distorting measurement results. The guard rings prevent current
at the surface of the insulation material from flowing from the
+measurement cable to the –measurement cable, instead of
through the insulation material itself.
ÐInsert the plug from the guard cable (Accessory Z580C) into
the appropriate jack in the test instrument.
ÐPlug the alligator clip onto the guard cable test probe.
ÐConnect the alligator clip to the guard ring between the two
measuring points at the insulation material under test.
ÐRefer to section 5.2 on page 12 regarding the measuring se-
quence.
Note
The following materials can be used as guard rings: alu-
minum foil, copper foil or metallic hose clamps.
!
!
+Measurement Cable
–Measurement Cable
Guard Cable
Conductor
Insulation
Material
Guard Rings
Contact Ring
(COM)

GMC-I Messtechnik GmbH 15
6 Measuring Direct, Alternating and
Pulsating Voltage – V Function
You can measure direct voltage, as well as sinusoidal alternating volt-
age with frequencies ranging from 45 to 65 Hz with this test instrument
.
Pointer deflection at the measuring instrument is always positive
for the measurement of direct voltage, regardless of the polarity of
the connections. Alternating voltage is always indicated as an
RMS value.
Voltage measurement is used to test for the absence of voltage
before performing the insulation resistance measurement, as well
as for automatic discharging of capacitive devices under test. The
falling voltage value can be observed at the display.
ÐSelect the V measuring function with the rotary switch, LED ➃
lights up permanently.
ÐConnect the measurement cables to the +and COM jacks.
ÐContact the measuring point with both test probes.
Attention!
!
A double acoustic signal is generated and the Caution!
LED lights up red in order to indicate the presence of
voltage of greater than 50 V.
ÐRead the measured value from the V scale. The measured
value is displayed directly – without pressing the START key.
ÐAfter completing the measurement, switch the instrument off
by turning the rotary switch to the OFF position.
Note
No more than the maximum permissible voltage of
1000 V may be applied. Input impedance for the voltage
measuring range is roughly 10 M.
The START and CONTIN./ZERO keys have no function in this case.
!
+
COM
+
COM
SHIELD GUARD
L1
L2
N
PE
L3
RB
R
E
Max.
1.2 kV
U
V4

16 GMC-I Messtechnik GmbH
7 Measuring Low-Resistance of up to 5 
– RLO Function
According to the regulations, the measurement of low-resistance at
protective conductors, earth conductors or equipotential bonding
must be performed with (automatic) polarity reversal of the test volt-
age, or with current flow in one direction, and then in the other.
Attention!
!
In the measuring function RLO, measurements are per-
formed with currents higher than 200 mA.
Please check before measuring whether your DUT or
your circuit is designed for these high current values.
Connection
Note
Low-resistance can only be measured at voltage-free
objects.
ÐConnect the device under test to the +and COM jacks.
ÐSelect the Rlo measuring function with the rotary switch.
Attention: The measurement cannot be started until the test
probes are in contact with the device under test.
If line voltage or interference voltage of greater than 50 V is
applied to the measurement inputs, this is indicated by means of
a double acoustic signal. Low-resistance measurement cannot be
started as long as interference voltage is present. The display is
not returned to low-resistance measurement until voltage is less
than approximately 8 V. If resistance is greater than 5 , LED ➃
blinks.
Measurement Types
You can choose one of two different types of measurement:
• Measuring sequence with automatic polarity reversal (reversal
of current flow direction) via the START key
• Manual measurement with positive polarity via the CONTIN./
ZERO key
+
COM
+ COM
10 M 
GUARD SHIELD
RLO
R < 5 
RLO
Rx
0V!
!
RLO 4
➃

GMC-I Messtechnik GmbH 17
7.1 Measurement with Automatic Polarity Reversal
ÐStart measurement in both current flow directions by briefly
pressing the START key, the LED ➃lights up during measure-
ment.
After the measuring sequence has been started, the instrument
performs measurement with automatic polarity reversal, first with
current flow in one direction (), and then in the other ().
Measurement is executed in the background. During both mea-
surements, the pointer briefly moves back towards 0 , indicating
to the user that measurement is being performed with both polar-
ities in the background.
The respectively larger (worse) measured value is displayed when
measurement has been completed (after the relay has audibly
switched two times).
The Limit LED lights up in order to indicate that the measured
value is valid. When the Limit LED and ➃ go out, the measure-
ment has been completed and the pointer returns to its neutral
position.
Limit Value Indication
If the measured value is less than or equal to 2 , the Limit LED
lights up green. If the measured value is greater than 2 , the Limit
LED lights up red.
Resistances which do not demonstrate a stable value until after a
“settling in period” should not be measured with automatic polar-
ity reversal. In this case, measurement with automatic polarity
reversal may lead to varying and/or inflated measurement values,
and thus to an ambiguous reading.
7.2 Measurement with Manual Polarity Reversal
In order to determine whether or not test results are independent
of current flow direction, measurement can be performed manu-
ally in one direction of current flow (positive polarity). Measure-
ment in the other direction of current flow (negative polarity) is
then conducted by switching the test probes.
ÐStart continuous measurement by briefly pressing the CONTIN./
ZERO key, the LED ➃lights up during measurement.
The red or green Limit LED indicates whether or not the limit value
has been violated (see section 7.1).
Measurement takes up to 3 minutes, after which the instrument is
switched to the standby mode. If you want to stop measurement
prematurely, press the CONTIN./ZERO key once again, after which
the relay switches audibly. Measurement is ended after roughly 5
seconds.
Differing results indicate voltage at the device under test (e.g.
thermovoltage or unit voltages).
Measurement results can be distorted by parallel connected
impedances in load current circuits and by equalizing current,
especially in systems which make use of “overcurrent protection
devices” (previous neutralization) without an isolated protective
conductor. Resistances which change during measurement (e.g.
inductance), or a poor contact, can also cause distorted mea-
surements.
Examples of resistances whose values may change during mea-
surement include:
–Incandescentlampresistance with changing values caused
by warming due to measuring current
– Resistances with a large inductive component
In order to assure unambiguous measurement results, causes of
error must be located and eliminated.
Limit
< Limit RLO
= OK 3

18 GMC-I Messtechnik GmbH
7.3 Taking Measurement Cables and Extension Cables into
Account (up to 5 ) – ZERO Function (Roffset)
Ohmic measurement cable resistance can be subtracted from the
measurement results automatically. Proceed as follows:
ÐSelect function Rlo with the rotary selector switch.
ÐShort circuit the test probes at the ends of the measurement
cables.
ÐPress and hold the CONTIN./ZERO key.
ÐAdditionally press the measuring range selection key
(10k–1T/100k–100M) until the pointer indicates “0”.
LED ZERO/FUSE ➅ lights up red permanently:
ÐRelease both keys.
During the course of subsequent low-resistance measurements,
cable resistance ROffset is taken into consideration, i.e. subtracted,
as long as the rotary selector switch is not turned to the OFF posi-
tion. Perform low-resistance measurement as described above in
the preceding pages. The stored value is retained, even if the
instrument has meanwhile been in standby operation provided
that the rotary selector switch position has not been changed.
8 Test Resistor for Insulation Measurement for
Checking the Insulation Measuring Instrument
According to section 5.3.1.2 of VDE 0105-100 (EN 50110-1), the
following applies: “These measuring instruments must be tested
before, and if applicable after use.”
The two outermost
metallic jacks on the connection panel must
be connected to each other internally via a 10 Mtest resistor to
this end.
The sum of test resistor and cable resistance (for both cables),
including test probes, amounts to 10 M±5%. This value allows
for quick self-testing.
ÐConnect the measurement cables to the +and COM jacks.
Ð Insert the test probes into the above described metallic jacks.
ÐSelect the Riso/ins measuring function with the rotary switch,
as well as the desired test voltage, e.g. RiSO 100 V.
ÐPress the start key and view the measurement results.
The pointer should remain frozen at 10 Mfor about 5 seconds.
When the Limit LED and the LED for measuring range ➀both go
out, the measurement has been completed and the pointer
returns to its neutral position.
+
COM
+
COM
SHIELD GUARD
10M RISO/RINS
10 M

GMC-I Messtechnik GmbH 19
9 Technical Data
1Accuracy specified here is only achieved with the following optional accessory:
“shielded high-resistance measurement cable KS-C (article number Z541F)”.
2Relative to scale length:
Scale 1: 83.13 mm
Scale 2: 75.05 mm
Scales 3 and 4: 67.02 mm
3Within the identified range on the respective scale (nominal range of use)
4) with ZERO balancing
5) 0.17 ... 2 : 20%
Meas.
Qty.
Scale /
Standard
Measuring
Range
Nominal Range
of Use
Nominal / Open-
Circuit Voltage
Nominal
Current IN
Short-
Circuit Cur-
rent IK
Intrinsic Uncertainty
under Reference
Conditions 2
Measuring
Uncertainty 3Overload Capacity
RINS VDE 0413
100 k...
100 M100 k... 10 M
50 V /100 V:
1.25 UISO
250 V /500 V /
1000 V:
1.1 UISO
1 mA 5 mA
2.5% 30% of
measured value 1000 V AC/DC
TRMS
10 k... 1 T100 k...
100 G2.5% 1
RLO 0 ... 5 0.17 ... 4 4) 4 V < U
0
< 6 V Test current IN200 mA 2.5% 10% 5) of
measured value
1000 V AC/DC
TRMS
U
AC/DC 0 ... 1000 V 10 ... 1000 V — — — 2.5% — 1000 V AC/DC TRMS
UBAT 8 ... 12 V 8.5 ... 12 V — — — —
2
1
3
4
5
1
2
4
53

20 GMC-I Messtechnik GmbH
Displays
Analog display
Measuring movement Moving-coil mechanism with core magnet
Scale length 83.13 mm (longest scale)
Limit LED LED lights up red to indicate an exceeded
limit value. LED lights up green to indicate
compliance with the limit value.
LED LED lights up red to indicate the presence
of interference voltage (when instrument is
switched off), test voltage during insulation
measurement or residual voltage after
insulation testing (U > 50 V)
Analog display LEDs Description see page 5
Reference Conditions
Reference temperature +23C3K
Relative humidity 40 ... 75%
Measured quantity
frequency
45 Hz ... 65 Hz
Measured quantity
waveform Sine, deviation between TRMS and recti-
fied value < 1%
Battery voltage 9.5 V 0.1 V
Test resistor 10 M1%
Normal position
of use 30°
Electrical Safety
Standard
VDE regulation VDE 0411, part 1, 1994-03
Protection class II
Pollution degree 2
Measuring category
CAT II 1000 V / CAT III 600 V / CAT IV 300 V
Fuses
Fuse link
FF315mA/1000V, effective in all resistance
measuring ranges, 1 additional replace-
ment fuse in the battery compartment
Electronic fuse for the protection of low-resistance mea-
surement RLO
Electromagnetic Compatibility (EMC)
Interference emission EN 61326-1:2006 class B
Interference immunity EN 61326-1:2006
Power Supply
Batteries 8 ea. 1.5 V mignon cell (8 ea. size AA)
(alkaline manganese per IEC LR14) or 8
rechargeable NiMH batteries (must be
recharged externally)
Nominal range of use 8.5 ... 12 V
Battery test
Battery capacity display via the Bat. TEST key
Battery saver circuit Standby function
Service life For RINS (1000 V / 1 M) and RLO with 20
s on-time and 1 measurement each for a
duration of 5 s
– With batteries (alkaline manganese):
900 measurements
– With rechargeable batteries (2000 mAh):
850 measurements
Safety shutdown If supply voltage is too low, the instrument
is switched off, or cannot be switched on.
When the rotary switch is set to the OFF
position, the instrument is completely dis-
connected from the batteries (after
approximately 10 seconds).
!