GOSSEN METRA HIT 27M, METRA HIT 27I User Manual

Operating Instructions

METRAHIT⏐27

METRA HIT 27M: Digital Multimeter and Milliohmmeter
METRA HIT 27I: Digital Multimeter, Milliohmmeter and Megohmmeter

3-349-207-02

8/12.10

Symbols used in the Digital Display

1

2

3
4

5

6

8

7

7

max. 600 V !

1

10

9

64 53

7

8

2

1 Main display with decimal point and polarity display

2 Auxiliary display with decimal point and polarity display

3 : Multimeter in continuous operation,

4 REM: Memory mode operation, disappears after communication

5 ZERO: Zero balancing

6 MAN: Manual measuring range selection

7 Unit of measure (if blinking, refer to chapter 11.2 on page 16 and

8 MIN/MAX: Display of smallest/largest recorded values

9 : Acoustic signal enabled,

1Display (LCD)

2 ON|OFF key

10 : Low storage battery voltage (< 3.3 V), recharge storage

Operating mode menu: open submenus / acknowledge entries
METRA HIT 27I: background illumination ON / OFF

3 DATA| CLEAR key for following functions: save measured value,

delete and MIN/MAX
Operating mode menu: Selection of individual menu items

against direction of flow / increase values

4 MAN|AUTO key for manual measuring range selection

Operating mode menu: Selection of individual menu items

in direction of flow, decrease values

5 FUNC key for selecting functions, start key INS measurement

Operating mode menu: Exit menu level and return to a higher level/

exit parameters configuration without saving data

6 Rotary selector switch for measuring function

7 Connector jacks *

8 Connector jacks for mains power battery charger NA HIT 2x

(only with storage batteries inserted)

⊥

Earthing input

*

S- Sense –, for 4-wire connection only with
S+ Sense +, for 4-wire connection only with Ω/mΩ/mΩ@1A
V;

Ω; °

C, MΩ measurement input

2 GMC-I Messtechnik GmbH

Ω/mΩ/mΩ@1A

Standard Equipment

Type 27M 27I 27AS

Article Number M227A M227B M227C

Instrument METRA HIT 27M 27I 27I
3 size AA NiMH storage batteries •• •
KS17S measurement cable set •• •
operating instructions •• •
abbreviated operating instructions •• •

GH18 protective rubber cover with
carrying strap

DKD calibration certificate •• •
Charging unit NA HIT 2x — ••
Kelvin clips KC4 (1 set = 2 each) — ••

Kelvin probes KC27 (1 set = 2 each)
Hard case HC30 — — •

USB-Adapter, USB cable, METRA­win 10 and METRAwin 90-2 soft­ware

ON blinks at transmission frequency in transmission mode

via the interface is ended by means of key or switch operation

chapter 15 on page 26)

with time specification

beeper is activated for corresponding function

batteries

•• •

—— •

—— •

Table of Contents

Page Page

1 Safety Features and Precautions ...............................4

2 Initial Start-Up ............................................................5

3 Selecting Measuring Functions and Measuring

Ranges .......................................................................6

3.1 Automatic Measuring Range Selection ..................................... 6

3.2 Manual Measuring Range Selection ......................................... 6

3.3 Quick Measurements ..............................................................7

4 Triple Digital Display ..................................................7

5 Measured Value Storage ............................................8

5.1 Measured Value Storage – Key Function “DATA”

(Hold/Compare) ...................................................................... 8

6 Saving Minimum and Maximum Values

“MIN/MAX” with Time Stamp .....................................9

7 Voltage and Frequency Measurement ......................10

7.1 Voltage Measurement [V] ...................................................... 10

7.1.1 Zero Balancing in the 3 V DC Measuring Range ...................... 10

7.1.2 Transient Overvoltages .......................................................... 10

7.1.3 Voltage Measurements at Above 600 V .................................. 10

7.2 Frequency Measurement [Hz] ................................................ 11

8 Resistance and Diode Measurements ......................11

8.1 Resistance Measurement (2-wire connection) [Ω] .................. 11

8.1.1 Zero Balancing in the 300 Ω and 3 kΩ Measuring Ranges .....11

8.2 Continuity Test during Resistance Measurement ....................12

8.3 Diode Measurements ...........................................................12

9 Milliohm Measurement (4-Pole-Measurement) .......13

9.1 Compensation of Cable Resistance ........................................ 13

9.1.1 Measurement with Kelvin Probe KC27 ................................... 13

9.2 Thermovoltage Compensation ................................................ 13

9.3 Milliohm Measurement with 200 mA or 20 mA DC [mΩ] ........ 14

9.4 Milliohm Measurement with 1 A Pulsating Measuring
Current [mΩ@1 A]
(automatic thermovoltage correction in 3…

300 mΩ

range) ...........14

10 Temperature Measurement [°C] ..............................14

11 Insulation Resistance Measurement [MΩ@...V]

(METRA HIT 27I only) ................................................15

11.1 Preparing for Measurement ...................................................15

11.2 Insulation Resistance Measurement ....................................... 16

11.3 Ending the Measurement and Discharging .............................. 16

12 Using the Menus – from the Initial InFO Menu to

Operating and Measuring Parameters ..................... 17

12.1 Sampling rAtE ........................................................... 17

12.2 Saving Measured Values ....................................................... 17

12.2.1Memory Mode – DATA Key Function (see also chapter 5.1) ..... 17

12.2.2Memory Mode Operation – STORE Menu Function .................. 18

12.3 Querying Memory Occupancy – INFO  MEMO/OCCUP ......... 18

12.4 Clearing the Memory – MEMO  CLEAr ................................ 18

12.5 Activating the Default Values ................................................. 18

12.6 Transmission Mode Operation with RS 232 Interface .............. 19

13 Characteristic Values ..................................... 22

14 Maintenance ............................................................ 25

14.1 Storage Batteries and Batteries ............................................. 25

14.2 Fuses ................................................................................... 26

14.3 Housing ............................................................................... 26

14.4 Device Return and Environmentally Compatible Disposal ......... 26

15 Multimeter Messages ..............................................26

16 Accessories ............................................................. 27

17 Repair and Replacement Parts Service,

Calibration Center* and Rental Instrument Service . 27

18 Guarantee ................................................................ 28

19 Product Support ....................................................... 28

20 Recalibration ............................................................ 28

GMC-I Messtechnik GmbH 3

1 Safety Features and Precautions

Attention!

!

Attention!

!

Attention!

!

Warning!

You have selected an instrument which provides you with
high levels of safety.

This instrument fulfills the requirements of the applicable
European and national EC guidelines. We confirm this with
the CE marking. The relevant declaration of conformity can
be obtained from GMC-I Messtechnik GmbH.
The METRA HIT27 is manufactured and tested in
accordance with safety regulations IEC 61010–1:2001 /
DIN EN 61010–1:2001 / VDE 0411–1:2002. When used for
its intended purpose, safety of the operator, as well as that of
the instrument, is assured. Their safety is however not
guaranteed, if the instrument is used improperly or handled
carelessly.

In order to maintain flawless technical safety conditions, and to
assure safe use, it is imperative that you read the operating
instructions thoroughly and carefully before placing your instrument
into service, and that you follow all instructions contained therein.

Observe the following safety precautions:

• The instrument may only be operated by persons who
are capable of recognizing contact hazards and taking
the appropriate safety precautions. Contact hazards exist
anywhere, where voltages of greater than 33 V (RMS)
may occur.

• Avoid working alone when taking measurements which
involve contact hazards. Be certain that a second person
is present.

Maximum allowable voltage between any given connector
jack and earth is 600 V, category II.

Nominal system voltage may not exceed 600 V.
Voltage measurements may only be performed with
the selector switch set to the V or the V~ position.
If the multimeter sockets are confused with the sense
sockets, the instrument may be damaged and the
operator may be subjected to danger!

• No measurements may be made with this instrument in
electrical circuits with corona discharge (high-voltage).

• Special care is required when measurements are made in
HF electrical circuits. Dangerous pulsating voltages may
be present.

• Measurements under moist ambient conditions, or with
an instrument with condensation moisture are not
permitted.

• Be absolutely certain that the measuring ranges are not
overloaded beyond their allowable capacities. Limit
values are listed in chapter 13 on page 22.

• The instrument may only be used in power installations if the
electrical circuit is protected with a fuse or circuit breaker with
a maximum rating of 20 A, and the nominal voltage of the
installation does not exceed 600 V.

• Maximum allowable interference voltage between the
jacks (7) and earth briefly amounts to 600 V
selector switch positions in the event of an error. The fuse
blows at an interference voltage value of > 3 V in the mΩ
range.

• Be prepared for the occurrence of unexpected voltages
at devices under test (e.g. defective devices, after testing
coil resistance at contactors etc.), for example,
capacitors may be dangerously charged. In the interest of
safety, always test for the absence of voltage first with
the selector switch in the V and V~ positions.

• In order to avoid damage to the instrument when
interference voltages are applied (within allowable limit
values), the mΩ measuring circuit is equipped with an
F1.6A/1000 V fuse, which makes this measuring circuit
highly resistive if excessive current should occur in the
event of a fault for the duration of overloading.

• Do not plug the mains power battery charger into the
instrument if normal batteries have been installed instead of
storage batteries.

The instrument may not be operated in explosive
atmospheres, or connected to intrinsically safe
electrical circuits.

RMS

in all

Contact hazard!

Dangerous voltages at the external jacks may be
looped through to the sense sockets during voltage
measurement. Therefore do not touch the sense
sockets.

• Be prepared for the occurrence of unexpected voltages
at devices under test (e.g. defective devices). For
example, capacitors may be dangerously charged.

• Make certain that the measurement cables are in flawless
condition, e.g. no damage to insulation, no interruptions
in cables or plugs etc.

4 GMC-I Messtechnik GmbH

Meanings of symbols on the instrument:

Warning!
Attention!

!

Attention!

!

Note!



!

+

Consecutive number

Registration number
Date of calibration (year - month)

German calibration service calibration laboratory

B0730

01-08

DKD-K­19701

Warning concerning a source of danger
(attention: observe documentation!)

Ground

2 Initial Start-Up

Storage Batteries or Batteries

Refer to chapter 14.1 regarding correct storage battery or
battery installation.

Mains power battery charger connection for
recharging storage batteries
(rechargeable batteries)

Continuous, doubled or reinforced
insulation

CAT II Measurement category II device

Indicates EC conformity

This device may not be disposed with the trash.
For further details on the WEEE marking, please
refer to our website www.gossenmetrawatt.com
and enter search term ’WEEE’.

DKD calibration certificate (red label):

Repair, Parts Replacement and Balancing

When the instrument is opened, voltage conducting parts
may be exposed. The instrument must be disconnected from
the measuring circuit before the performance of repairs, the
replacement of parts, or balancing. If balancing, maintenance
or repair of a live open instrument is required, this may only
be carried out by trained personnel who are familiar with the
dangers involved.

Defects and Extraordinary Strains

If it may be assumed that the instrument can no longer be
operated safely, it must be removed from service and
secured against unintentional use.
Safe operation can no longer be relied upon,

• If the instrument or the test probes are damaged

• If the instrument no longer functions

• After long periods of storage under unfavorable
conditions (e.g. humidity, dust, or excessive
temperature), see „Ambient Conditions“, page 24.

The mains power battery charger may not be
connected if normal batteries (which are not suited for
recharging) have been inserted: Danger of explosion!

As a result of internal voltage monitoring, the
instrument may respond as follows if the battery
charge level is low:
– Cannot be switched on
– Shuts back down immediately
– Shuts back down immediately when a load is

applied in the mΩ range

If this is the case, replace or recharge the storage

batteries.

The mains power battery charger may only be used to
recharge the storage batteries!

Mains power battery chargers with an output voltage of
greater than 5 V may not be used. The milliohmmeter’s
internal voltage regulator might otherwise be destroyed.
No guarantee claims can be accepted if any mains
power battery charger other than the
(available as an accessory).

Switching the Instrument On Manually

Ð Press the ON|OFF key.

As long as the key is held depressed, all of the segments
at the LCD are illuminated. The LCD is shown on page 2.
Power-up is acknowledged with a brief acoustic signal.
The instrument is ready for use as soon as the key is released.

Switching the Instrument On with a PC

After transmission of a data frame from the PC, the
multimeter is switched on. See also chapter 12.6.

Switching the Instrument On Automatically

The multimeter is switched on automatically in the
transmission and memory modes.

Electrical discharge and high frequency interference
may cause incorrect displays to appear, and may
disable the measuring sequence. In such cases,
switch the instrument off and back on again in order
to reset. If the problem persists, briefly dislodge the
storage batteries from the connector contacts.

NA HIT 2x

is used

GMC-I Messtechnik GmbH 5

Setting Time and Date

See chapter 12 on page 17.

Switching the Instrument Off Manually

Ð Press and hold the ON|OFF key until OFF appears at the

display.

Shutdown is acknowledged with two, brief acoustic signals.

Switching the Instrument Off Automatically – SLEEP MODE

The instrument is switched off automatically if none of the
keys or the rotary switch are activated for approximately 10
minutes. Shutdown is acknowledged with a brief acoustic
signal.

Transmission mode: In this case, checking is first performed to
determine whether or not the sampling rate has been set to a
value of greater than 10 s. The instrument is switched off after
10 minutes, but the instrument is reactivated 10 s before data
is to be saved to memory. The instrument is then switched
back off again.

In the transmission mode, the instrument can be manually
activated with the ON| OFF key. After activation of this type, the
instrument returns to the “SLEEP MODE”.
If the instrument is to be fully shut down, it must first be
activated and then switched off with the ON| OFF key. This
ends both memory mode and transmission mode operation.

We recommend setting the instrument to continuous
operation for transmission mode operation.

The continuous operation mode is not effected by automatic
shutdown.

Disabling Automatic Shutdown

The instrument can be set to continuous operation.
Ð Press and hold the FUNC key and then switch the

instrument on by pressing the ON| OFF key. Continuous
operation is indicated at the display with the symbol.

Switching LCD Illumination On and Off (METRA HIT 27I only)

Ð Briefly press the ON |OFF key after the instrument has

already been switched on.

Illumination is switched off automatically after approximately 2
minutes.
Note: Electrical discharge and high frequency interference
may cause incorrect displays to appear, and may disable the
measuring sequence. In such cases, switch the instrument
off and back on again in order to reset. If the problem
persists, briefly dislodge the storage batteries or batteries
from the connector contacts.

Disconnect the instrument from the measuring circuit before
opening and refer to chapter 14.1, “Storage Batteries and

Batteries”!

3 Selecting Measuring Functions and Measuring Ranges

3.1 Automatic Measuring Range Selection

The multimeter is equipped with auto-ranging for all
measuring ranges, except for temperature measurement, and
diode and continuity testing. Auto-ranging is active as soon
as the multimeter is switched on. The instrument
automatically selects the measuring range which allows for
highest possible resolution for the applied quantity. When the
instrument is switched to frequency measurement, the
previously selected voltage measuring range remains active.

The instrument automatically switches to the next highest or
next lowest measuring range for the following measured
quantities:

Switching to next

Measuring Ranges

V~, V , Hz, Ω, mΩ,

30 / 300 mΩ at 1 A

3 mΩ@1A, MΩ@...V 3¾ 3100 280

Resolu-

highest range

tion

at ±(... d +1 d)

4¾ 31,000 2800

3.2 Manual Measuring Range Selection

Auto-ranging can be deactivated and measuring ranges can
be selected manually in accordance with the following table.

The manual mode is deactivated by pressing and holding the
MAN|AUTO key (approx. 1 s), by activating the rotary switch, or
by switching the instrument off and then back on again.



MAN|
AUTO

Manual mode active:

short

utilized measuring range is fixed

Range switching sequence for:

V: 3V→ 30 V → 300 V → 600 V → 3V→…
Hz: 300 Hz → 3kHz→ 300 Hz → …

short

Ω:

30 MΩ→ 300

mΩ:30mΩ→ 300 mΩ→ 3 Ω→ 30 Ω→ 30 mΩ→ …
mΩ@1A: 3 mΩ→30 mΩ→300 mΩ→3mΩ→ …

long Return to automatic range selection

Function

Ω→ 3kΩ→

30 k

Ω→

300kΩ→ 3M

Automatic range selection is disabled as long as the
MIN/MAX function is active.

Switching to next

lowest range

at ±(... d -1 d)

Ω→

…

Acknow-

ledgement

Dis-

Acoust.

play

Signal

MAN 1 x

MAN 1 x

—

2 x

6 GMC-I Messtechnik GmbH

3.3 Quick Measurements

23.000

MIN MAX

10.000 24.000

V

Auxiliary Display MIN

Main Display

Auxiliary Display MAX

If you wish to perform quicker measurements than those pos­sible with the automatic measuring range selection function,
make sure to establish the appropriate measuring range:

•by manual measuring range selection, i. e. by selecting the
measuring range with the best resolution, see
chapter 3.2.

or

•via DATA function, see chapter 5. After the first measure-
ment, the proper measuring range will be automatically
determined so that measurements are performed more
rapidly from the second measured value onwards.

With both functions, the established measuring range is
maintained for the subsequent series mode measurments.

4 Triple Digital Display

The three digital displays (1 main display and 2 auxiliary
displays) show the measured value with decimal and plus or
minus sign. The selected unit of measure is displayed as well.
A minus sign appears to the left of the value during the
measurement of zero-frequency quantities, if the plus pole of
the measured quantity is applied to the “⊥” input.

“OL” (overload) appears if the measuring range upper limit is
exceeded for the following measured quantities:
V AC, V DC, Hz, Ω,
3 mΩ at 1 A, , MΩ

The digital display is refreshed at different frequencies for the
various measured quantities.

The main display appears immediately after the multimeter is
switched on, but the auxiliary displays have to be activated by
pressing the DATA|CLEAR key (except for position MΩ@...V,
where the auxiliary displays appear immediately upon
selecting the function).

This assures that any undefined existing condition which
prevailed when measurement was started is not continuously
displayed as a maximum value, e.g. no-load operation.
In the following flowcharts, the initial displays are highlighted
through the use of a bold border line.

, mΩ, 30 / 300 mΩ at 1 A: 30999

@...V: 3099

GMC-I Messtechnik GmbH 7

5 Measured Value Storage

Acoustic Signal

30.000

20.000 data

V

30.000

MIN MAX

20.000 30.000

V

DATA

DATA

MAN

The METRA HIT27 provides two entirely different options for
storing data:

• Measured Value Memory – DATA Key Function:
Each time a measuring point is contacted, a measured
value is stored in accordance with a defined condition
(see chapter 5.1).

• Memory Mode Operation – STORE Menu Function:
After activating the STORE menu function, all measured
values are saved in accordance with the selected
sampling rate. Memory mode operation is ended
manually using the same menu function, see
chapter 12.2.

In both cases, saved measured values can be read out with
the help of METRAwin



10 PC software (as of version 5.22).
However, read-out is only possible if a BD232 IR adapter has
been plugged into the METRA HIT27 and connected to the
PC with an interface cable.

5.1 Measured Value Storage – Key Function “DATA”

(Hold/Compare)

Measured values can be automatically “frozen” with the DATA
hold function. This is useful when, for example, contacting
the measuring points with the test probes requires your full
attention.

Memory should be cleared before starting a measurement
series with the DATA key function.
This assures, on the one hand, that adequate memory
capacity is available and, on the other hand, that only data
from the last measurement series are read out in a contigu­ous fashion. Check current memory occupancy to this end:
INFO  MEMO/OCCUP
Clear memory if required: MEMO  CLEAr.

After the measured value has been applied and the
corresponding “condition” from the table below has been
fulfilled, the measured value appears at the left-hand auxiliary
display and 2 acoustic signals are generated. At the same
time, “MAN” appears, indicating that the measuring range is
now fixed. The test probes can now be removed from the
measuring points, and the measured value can be read from
the auxiliary display. If the measured value is less than the
value specified in the table, the instrument is reactivated for
storage of the next value and “data” blinks at the display. The
measured value is saved to non-volatile memory, which is
acknowledged by an acoustic signal in each case.

Comparison of measurement values (DATA Compare)

If the newly stored measurement value deviates less than

0.33% of the measuring range from the first measurement
value, the acoustic signal (DATA Compare) sounds twice.
If it deviates more than 0.33% from the measuring range,
only a brief signal sonds.

Function

DATA

Switch on brief

Store
(stabilized mea­surement value)

Reactivate

Switch to

function

MIN/MAX

Quit long

1)

Reactivation results from falling short of specified measured value limits.

2)

When a measurement value is stored for the first time as a reference value, the
acoustic signal sounds twice.
For subsequent data hold, two acoustic signals are only generated if the
currently frozen value deviates from the fist saved value by less than 0.33% of
the measuring range, depending upon resolution.



DATA

1)

brief see Table chapter 6

Condition Response at Instrument

Measuring

Function

Ω,

Ω,

Measurement

Value

V, Hz > 10% of MR

0 L

V, Hz < 10% of MR stored

0 L

Sub-Display

Meas.

Value

is

displayed

meas.

value

is

deletedisdeleted

DATA

is

displayed

blinks

Key

R = measuring range, MV = measured value

As long as the DATA function is active, the measuring ranges
should not be changed manually.

The DATA function is deactivated if the DATA| CLEAR key is
pressed and held (approx. 1 s), by turning the rotary switch or
by switching the instrument off and back on again.

8 GMC-I Messtechnik GmbH

Acoustic

Signal

brief

brief
2x

2x

2)

6 Saving Minimum and Maximum Values

Note!



CLEAR

long

MIN

MAX

tMIN

MIN

tMAX

MAX

Current Measured Value

Current Measured Value

Current Measured Value

Current Measured Value

DATA

short

30.000

V

30.000

10.000 data

V

30.000

MIN MAX

10.000 30.000

V

30.000

MIN

09:20:05 10.000

V

30.000

MAX

09:20:05 30.000

V

DATA

DATA

DATA

DATA

MAN

MAN

MAN

blinks

“MIN/MAX”

Minimum and maximum values can be displayed at the
auxiliary displays for long-term observation of measured
quantities.

Ð Press the DATA | CLEAR key twice: Current MIN and MAX

values appear at the auxiliary displays.

Automatic range selection is disabled as long as the
MIN/MAX function is active.

Ð Press the DATA | CLEAR key once again for a display of the

minimum value and the time of its occurrence.

Ð Press the DATA | CLEAR key once again for a display of the

maximum value and the time of its occurrence.

The MIN and MAX values are deleted by pressing and holding
the DATA|CLEAR key (approx. 1 s), by turning the rotary switch,
or by switching the instrument off and back on again.

Function

MIN/MAXDATA

1.

Save

2.

Save and

Display

3.

Return to 1 short

Stop

No new MIN/MAX values are calculated for a period
of 2 to 4 seconds after the measuring range has been
changed (depending upon measuring function), in
order to allow measured values to settle in.

with Time Stamp

MIN and MAX

Measured Values /

2 x short are

short

short t and

long

Time of

Measurement

saved

are

saved

are

saved

are deleted is deleted

Response from Instrument

Display

Main Display

Current

measured value

same as 1

Aux.

Display

MIN and

MAX

t and

MIN

MAX

same as

1

is

deleted

Acoustic

Signal

1 x

1 x

1 x

1 x

2 x

GMC-I Messtechnik GmbH 9

7 Voltage and Frequency Measurement

Note!



Attention!

!

FUNC FUNC

V

Hz

V~

Hz

226.000

050

.

00

mΩ

S+S–

VΩ°C

– (+)
~

+ (–)
~

max. 600 V (3 kHz)

V: 0.1 mV … 600 V
Hz: 1Hz … 3kHz

Measuring Ranges:

m

Ω

S+S–

VΩ°C

Voltage Measurements at Above 600 V
with the HV3 High-Voltage Probe

black

black

red

x1000

x100

7.1 Voltage Measurement [V]

Ð Select voltage type V or V~/Hz with the rotary selector

switch as appropriate for the measured quantity.

Ð Connect the measurement cables as shown.

The “⊥” connector jack should be grounded.

Ð The V~/Hz selector switch position: Each time the FUNC key is

pressed, voltage and frequency measurement are
alternately selected, and switching is acknowledged with
an acoustic signal. The respective measured quantity is
displayed at the LCD.

An intermittent acoustic signal warns the operator if
the measured value exceeds the upper range limit in
the 600 V range.

Make sure that a current measuring function (Ω, mΩ,

MΩ) or a C measuring function (°) has not been
selected when the multimeter is connected for

voltage measurement!
If fuse blowing limits are exceeded as a result of
operator error, both the operator and the instrument
are in danger!

7.1.1 Zero Balancing in the 3 V DC Measuring Range

Ð Select the 3 V measuring range.
Ð Plug the measuring cables into the instrument and

connect the free ends to each other.

Ð Press the FUNC key.
The instrument acknowledges zero balancing with an
acoustic signal, and „0.0000 V“ and the “ZERO” symbol appear
at the display. The voltage value measured at the moment the
key is pressed serves as a reference value (2000 digits). It is
automatically subtracted from all subsequent measured
values. If the measuring range is changed (MAN key), the
ZERO function only remains active (at the display and in
memory) for the selected measuring range.

Ð Zero balancing can be deleted:
– By once again pressing and holding the FUNC key, which

is acknowledged with two acoustic signals
(ZERO is deleted in the display)

– By switching the instrument off

7.1.2 Transient Overvoltages

The multimeter is protected against transient overvoltages of
up to 4 kV with rise times of 1.2, and halftimes of 50 μs. For
measurements at transformers or motors with long pulse
durations etc., we recommend the use of our KS30
measuring adapter. It provides protection against transient
overvoltages of up to 6 kV with rise times of 10, and halftimes
of 1000 μs. It has a continuous load capacity of 1200 V
Additional influence error caused by the KS30 measuring
adapter amounts to approximately –2%.

7.1.3 Voltage Measurements at Above 600 V

Voltages of greater than 600 V can be measured with a high­voltage probe, e.g. the HV3
Messtechnik GmbH. It is absolutely essential to ground the
bonding terminal. Observe all applicable safety precautions!

1)

or the HV302) from GMC-I

RMS

.

10 GMC-I Messtechnik GmbH

1)

HV3: 3 kV

2)

HV30: 30 kV, for direct voltage only

7.2 Frequency Measurement [Hz]

Note!



Note!



0.L

kΩ

FUNC

0.5435

diode

V

FUNC

000..0

short

Ω

FUNC

Ω

mΩ

S+S–

VΩ°C

R

x

Voltage Drop

Ω: 10 mΩ … 30 MΩ

Overall measuring range:

+–

Ð Select the V~/Hz measuring function with the rotary

selector switch.

Ð Apply the measured quantity as described under voltage

measurement.

Ð Briefly press the FUNC key in order to measure frequency.

The frequency values appears at the main display. The
frequency measuring range can be selected
subsequently by pressing MAN|AUTO. The previously
selected voltage measuring range remains active.

Ð The instrument can be switched from frequency

measurement back to alternating voltage measurement
by pressing the FUNC key once again. This selection is
acknowledged with an acoustic signal.

Frequency measurement is only possible if the
measuring signal passes through zero (AC coupling).

8 Resistance and Diode Measurements

8.1 Resistance Measurement (2-wire connection) [Ω]

Ð Make sure that the device under test is voltage-free (see

chapter 7.1). Interference voltages distort measurement
results and damage the instrument!

Ð Set the rotary selector switch to “Ω”.
Ð Connect the device under test as shown.

High Impedance Measurements in the 3 MΩ / 30 MΩ
Range

In the event of extremely high resistances the
capacitive influence of the person performing the
measurement and/or the measuring cable may
distort the measured value.
Use therefore short or shielded measurement cables.

8.1.1 Zero Balancing in the 300 Ω and 3 kΩ Measuring Ranges

Cable and contact resistances can be eliminated for the
measurement of small resistance values in the 300 Ω and
3kΩ ranges by means of zero balancing:

Ð Plug the measuring cables into the instrument and

connect the free ends to each other.
Ð Press the FUNC key.
The instrument acknowledges zero balancing with an

acoustic signal, and „000.00 Ω“ or „0.0000 kΩ“ and the “ZERO”
symbol appear at the display. The resistance value measured
at the moment the key is pressed serves as a reference value
(max. 20 Ω, or 200 Ω, or 2000 digits). It is automatically
subtracted from all subsequent measured values. If the
measuring range is changed (MAN|AUTO key), the ZERO
function remains active (at the display and in memory).

Ð Zero balancing can be deleted:
– By once again pressing and holding the FUNC key, which

is acknowledged with two acoustic signals,
– By switching the instrument off.

GMC-I Messtechnik GmbH 11

8.2 Continuity Test during Resistance Measurement

Note!



mΩ

S+S–

VΩ°C

Conducting Direction

Reverse Direction

If the “acoustic signal ” function is activated and the
0 ... 310 Ω measuring range is selected, a continuous
acoustic signal is generated by the instrument within a range
of 0 to approx. 10 Ω.

Overflow “0l” is displayed where Rd > 310 Ω.

Activating and Deactivating Continuity Testing (acoustic signal)

Ð Set the rotary selector switch to „Ω//“.
Ð Repeatedly press the FUNC key until and “short” appear

at the display, provided the connector jacks are open
(Display 0.L).

Ð Connect the measurement cables to the device under

test.

Ð The instrument is switched to resistance measurement

by pressing the FUNC key once again.

8.3 Diode Measurements

Ð Make sure that the device under test is voltage-free (see

chapter 7.1). Interference voltages distort measurement
results!

Ð Set the rotary selector switch to „Ω//“.
Ð Briefly press the FUNC key for diode measurement. Unit of

measure “V” and “diode” are then displayed if the
connector jacks are open (Display 0.L).

Ð Connect the device under test as shown.

Conducting Direction and Short-Circuit

The instrument displays conducting-state voltage in volts. As
long as voltage drop does not exceed the maximum display
value of 3 V, several series connected components or
reference diodes can be tested.

Reverse Direction or Interruption

Overload (.0l) is displayed at the instrument for diode
measurements where Ud > 3.1 V. Measuring current is
always a constant current of approximately 1 mA.

Resistors and semiconductors which are connected
in parallel to the diode distort measurement results!

12 GMC-I Messtechnik GmbH

9 Milliohm Measurement (4-Pole-Measurement)

Note!



VΩ°C

m

Ω

S+S–

red

black

black

Milliohm measurement on
conductor bars, welds, coils
up to 1 H, etc. with Kelvin
probe KC27 (or Kelvin clip
KC4)

Direct the spring-loaded test
probes inward towards the DUT,
if possible, as they are con­nected via the red plugs with S

+

or S

–

(Sense) .

01.180

m Ω

FUNC

MAN

00.010

termoC

m

FUNC

01.170

m

FUNC

mΩ

Ω

Ω

ZERO

MAN

MAN

Measure
Thermo­voltage

Thermo­voltage
Compen­sated
Measure­ment
Results

long

30 mΩ∗/300 mΩ

∗

at 200 mA

Measuring Ranges:

MAN

FUNC

3 Ω /30Ω at 20 mA

mΩ

S+S–

VΩ°C

R

x

Voltage Drop Measuring Current

mΩ: 0,001 mΩ … 30 Ω

Overall Measuring Range:

+–

Measurement Cables,
KC27 or KC4

Note:

When using KC27 or
KC4 always set red
plug at S

+

or S–,

respectively.

9.1 Compensation of Cable Resistance

Electrical resistance is a dipole quantity which can generally
only be measured using two poles. This is accomplished by
directing a measuring current of predetermined magnitude
through the device under test, and measuring the resultant
voltage drop. The respective resistance value is derived from
the quotient of these two values.

The two points between which voltage is measured are
decisive as regards the results of the measurement. All
resistances between these two points add to the measured
resistance value. These include contact resistance, as well as
cable resistance. If a very low resistance value needs to be
measured, for example contact resistance at a contactor with
a value of only a few milliohms, the points between which
voltage is measured must be moved out of the measuring
instrument and positioned as closely as possible to the
device under test. For this reason, the measuring instrument
is equipped with separate jacks for current feed and voltage
measurement. This type of 4-pole connection is known as
connection according to Kelvin.

KC4 Kelvin clips and KC27 Kelvin probes (available as
accessories) allow for easy, correct connection.

9.1.1 Measurement with Kelvin Probe KC27

9.2 Thermovoltage Compensation

Thermovoltages which occur as a result of material and
temperature differences may distort measurement results. For
this reason, the instrument is equipped with automatic
thermovoltage compensation in the relevant measuring
ranges.

GMC-I Messtechnik GmbH 13

If the measuring current is interrupted during 4-wire­mΩ-measurement or if the fuse is defective, the
message „leads open“ flashes on the display.
If fuse is defective, see chapter 14.2.

9.3 Milliohm Measurement with 200 mA or 20 mA DC [mΩ]

Note!



Note!



0023.2

°C

sensr

pt1000 selCt

°C



Pt100

FUNC

FUNC

00.10

temp

Ω





Cable
Resistance



Pt1000 (TF220)
Ni100
Ni1000

0 … 50

Ω



+

pt1000



FUNC

RTD

°C / °F

rlead

Ð Make sure that the device under test is voltage-free (see

chapter 7.1). Interference voltages distort measurement
results!

Ð Set the rotary selector switch to “mΩ”.
Ð Connect the device under test as shown.

KC4 Kelvin clips and KC27 Kelvin probes (available as
accessories) allow for easy, correct connection.

Resistance at the current jacks should amount to <1Ω.
Ð If applicable, select the desired measuring range using

the MAN| AUTO key: 30 mΩ, 300 mΩ, 3 Ω or 30 Ω.

This measuring method is suitable for resistances with
inductances of up to 1 H.

Thermovoltage Correction in the 30/300 mΩ Range

Ð Press the FUNC key in order to measure thermovoltage.

Wait until the measured value has settled in. This may
take several seconds, depending upon inductivity. Then
press the FUNC key once again in order to return to the
milliohm measuring function. All future measurement
result will be corrected based upon the previously
measured thermovoltage value. ZERO appears at the
display in order to indicate active compensation.

Measurements at Inductive Devices

Coils in motors, choke ballasts and contactors are highly
inductive. Changes in current at inductive devices, including
switching the milliohmmeter on and off or changing the
measuring range, result in a corresponding voltage change.
These changes may be of significant magnitude, and may
result in arcing under unfavorable conditions. The
milliohmmeter is protected against arcing by means of
suitable voltage arrestors.

9.4 Milliohm Measurement with 1 A Pulsating Measuring

Ð Make sure that the device under test is voltage-free (see

chapter 7.1). Interference voltages distort measurement
results!

Ð Set the rotary selector switch to “mΩ@1A”.
Ð Connect the device under test as shown.

KC4 Kelvin clips and KC27 Kelvin probes (available as
accessories) allow for easy, correct connection.

Resistance at the current jacks should amount to <0.2Ω.
Ð If applicable, select the desired measuring range using

the MAN| AUTO key: 3mΩ, (30 mΩ or 300 mΩ)

Thermovoltage is compensated automatically.

14 GMC-I Messtechnik GmbH

Current [mΩ@1 A]
(automatic thermovoltage correction in 3…

Due to high current consumption during this
measurement, NiMH storage batteries should be
installed and the NA HIT 2x mains power battery
charger should be used.

300 mΩ

range)

10 Temperature Measurement [°C]

Resistance thermometers (available as accessories) are used
for temperature measurement. A 2-pole measurement is
utilized. Cable resistance is set to 0.1 Ω as a default value.

Selecting Temperature Unit of Measure and Sensor Type

Ð Set the rotary selector switch to “°C”. Press FUNC to

access the selection menu for temperature unit of
measure and sensor type. sensr and selCt are displayed.

Ð Press the FUNC key to select the desired temperature unit

of measure: °C or °F.

Ð Select the sensor type (RTD) with the  keys.
Ð Connect the sensor to the two jacks (see diagram).

The selected temperature unit of measure and sensor
type remain unchanged after exiting the function, and
when the instrument is switched off.

Adjusting Cable Resistance

Note!



Note!



Note!



mΩ

S+S–

VΩ°C

RTD

see chapter 14

Measuring Range:

- - - - -

V

-000 250 V

MΩ@

50 ... 500V

10.29

V

023 250 V

MΩ

Selected Test Voltage

Displays test voltage

as long as key is depressed

R

ISO

FUNC MAN

+

FUNC

Continuous
Measurement

Measuring voltage

/Residual voltage

approx. 2% accuracy

Nominal/
test voltage

Ð After selecting a resistance thermometer, the

measurement display is accessed by pressing the  key.

Ð The menu for cable resistance adjustment is opened by

simultaneously pressing the  and  keys. Rlead and
temp are displayed.

Ð The decade (i.e. the position of the digit to be changed) is

selected with the  keys, and the respective digit is
set with the  keys.

Ð The menu is exited upon acknowledging the last digit by

pressing the  key, whereupon the measuring display
returns. The cable resistance value remains in memory.
The default value is 0.1 Ω. Entry is limited to a range of 0
to 50 Ω.

The selected cable resistance value remains
unchanged after exiting the function, and when the
instrument is switched off.

11 Insulation Resistance Measurement [MΩ@...V]

(METRA HIT 27I only)

11.1 Preparing for Measurement

High-resistance measurements

In the event of extremely high resistances the
capacitive influence of the person performing the
measurement and/or the measuring cable may
distort the measured value. Use therefore short or
shielded measurement cables.
The measurement cables may not come into contact
with one another during high-resistance insulation
measurements.

Ð Set the rotary selector switch to “MΩ@50V”, “100V”,

“250V” or “500V”, depending upon the desired test

voltage.
Ð Connect the DUT as shown on the next page.

Interference voltage

The rotary selector switch may only be set to
MΩ@...V for insulation resistance measurement

GMC-I Messtechnik GmbH 15

(not for voltage measurement).
However, if interference voltage is inadvertently
applied with the switch in this position, it is displayed
at the bottom left. Insulation resistances may only be
measured on voltage-free objects.

If an interference voltage of > 50 V is present, insulation
resistance measurement is disabled. The LCD continues to
display the interference voltage value. If a voltage of greater
than 610 V is present, an acoustic signal is generated as well.

Note!



Testing the Measurement Cables

Attention!

!

Attention!

!

Note!



mΩ

S+S–

MΩ

R

ISO

U

Measured

(50 to 500V)

Ω: 10 k

Ω … 3GΩ

Measuring Range:

!

Initial testing should be performed by short-circuiting
the measurement cables using their test probes. The
instrument must display nearly 0 Ω. A broken
measurement cable can be detected in this way.

11.2 Insulation Resistance Measurement

Ð Press and hold the FUNC key until the display settles in, in

order to measure insulation resistance.

The selected and displayed test voltage blinks during
measurement.

Attention: Contact hazard!

Current voltage at the device under test appears at the
interference or residual voltage display during measurement.
This value is slightly less than nominal voltage.

Insulation resistance measurement is ended by releasing the
FUNC key.

Auto-ranging is active during insulation resistance
measurement. Manual measuring range selection is not
possible.

The instrument’s storage batteries are rapidly
depleted during insulation resistance measurement.
Only hold the multifunction key depressed as long as
is actually necessary. The continuous measurement
described below should only be performed if
absolutely necessary.
Use NiMH storage batteries only.

Do not touch the conductive ends of the test probes
when the instrument has been activated for the
measurement of insulation resistance.
You may otherwise be exposed to a current of

1.5 mA (limited in the measuring instrument), and
although this is not life endangering, the resulting
electrical shock is quite discernible.

If, on the other hand, measurement is being performed on
a capacitive device under test, for example a cable, it may
be charged to approximately ±600 V, depending upon the
selected nominal voltage.
Touching the device under test after measurement has
been performed may be life endangering in this case!

16 GMC-I Messtechnik GmbH

Continuous Measurement

Ð Activation: Briefly press the multifunction key and the

MAN| AUTO key simultaneously. This is acknowledged with
an acoustic signal.

Ð Deactivation: Briefly press the multifunction key.

11.3 Ending the Measurement and Discharging

After measurement has been completed, any remaining
residual voltage is displayed which may result from cable
capacitance. These charges are quickly dispersed by means
of two internal resistors with a value of 2 MΩ. However,
contact to the device under test must be maintained. The
falling voltage value can be observed at the interference or
residual voltage display.

Do not disconnect the device under test until the voltage value has
dropped to below 25 V!

12 Using the Menus – from the Initial InFO Menu to

Operating and Measuring Parameters

Menu-driven operation via the initial „1NF0 “ menu allows the
user to query online help, activate the memory and query
memory occupancy, activate the interface and configure
device parameters.

Ð The initial „1NF0 “ menu is accessed by simultaneously

pressing and holding the FUNC and ON |OFF keys with the
instrument switched on, until „1NF0 “ appears at the
display.

Ð The display can be switched from the main „1NF0 “ menu

to the other main menus including “store“, “memo”, “ send”
and “set”, and then back to the „1NF0 “ menu, by
repeatedly pressing the  keys.

Ð After accessing the desired main menu, the associated

submenus are opened by activating the  key.

Ð The desired parameter or the desired function is selected

by repeatedly pressing the  keys.

Ð Acknowledge with the  key in order to change the

corresponding parameter or parameters.

Ð After the desired digit has been selected with the 

keys and the value has been adjusted with the  keys,
the next digit is accessed with the  key, or the display is
returned to the start menu or switched to the next
submenu.

Ð The measuring mode is started by repeatedly pressing

the FUNC key until the measuring display appears.

Ð The multimeter is switched off by pressing and holding

the ON| OFF key until the display goes blank.

The following pages include an overview of the menu
structure.

12.2 Saving Measured Values

The METRA HIT27 provides two entirely different options for
storing data:

• Measured Value Memory – DATA Key Function:

Each time a measuring point is contacted, a measured

value is stored in accordance with a defined condition

(see chapter 5.1 and chapter 12.2.1).

• Memory Mode Operation – STORE Menu Function:

After activating the STORE menu function, all measured

values are saved in accordance with the selected

sampling rate. Memory mode operation is ended

manually using the same menu function.
In both cases, saved measured values can be read out with

the help of METRAwin
However, read-out is only possible if a USB-HIT IR adapter
has been plugged into the METRA HIT27 and connected to
the PC with an interface cable.

12.2.1 Memory Mode – DATA Key Function (see also chapter 5.1)

The instrument is equipped with a measured value memory
(32 kB) which is synchronized with a quartz movement, and
has an average capacity of 1000 measured values. Minimum
capacity is 800 measured values and maximum capacity is
1200 measured values.
Data are stored and can be transmitted directly to a PC with
the METRAwin
the storage batteries are depleted or the batteries or storage
batteries are replaced.
Measured values are stored in so-called blocks. Measured
values resulting from the same measuring function are saved
to the same block.

Only absolute values and absolute time stamps can be
saved, i.e. no relative or Δ values, and no relative time
stamps.

12.1 Sampling rAtE

The sampling rate specifies the time interval after which the
respective measured value is transmitted to the interface or to
measured value memory.

Certain sampling rate limit values apply to various measured
quantities, and these may not be exceeded (see table below).

Measured Quantity Sampling Rate

V0.5s
V ∼, 0.5 s

, °C (Pt100, Pt1000) 0.5 s

mΩ, Ω

Hz 1 s
mΩ@1A 1.5 s

Memory content can only be read out with the help of a PC,
an IR adapter (USB-HIT), and METRAwin
software.

Stored measurement data blocks are retained even if the
instrument is without voltage supply.

Preparing for Memory Mode Operation

Ð First set the sampling rate for memory mode operation,

and then start memory mode operation.

The sampling rate can also be changed during memory

mode operation.
Ð First select the desired measuring function and an

appropriate measuring range.
Ð Check the storage battery charge level before starting

long-term measurement recordings (see chapter 14.1 on

page 25). Connect the mains power battery charger if

applicable.



10 PC software (as of version 5.22).



10 software. Date and time must be reset if



10 analysis

GMC-I Messtechnik GmbH 17

12.2.2 Memory Mode Operation – STORE Menu Function

Attention!

!

Ð First set the sampling rate for memory mode operation,

and then start memory mode operation.
The sampling rate can also be changed during memory
mode operation.

Ð First select the desired measuring function and an

appropriate measuring range.

Ð Check the storage battery charge level before starting

long-term measurement recordings, see chapter 14.1 on
page 25. Connect the charger if necessary.

Starting Memory Mode Operation with Menu Functions

Ð Open the “Operating Mode” menu (refer to the menu

diagram) and select the StorE function.

Ð Now activate the  key to open the start menu for

memory mode operation: StArt blinks.
Activate the  key once again in order to start memory
mode operation: REM appears at the display.

Ð Press the  key in order to switch to the measuring

function.
A new memory block is created when another measuring
function is selected with the rotary switch or the FUNC key.
Data storage then continues automatically. The “SLEEP
MODE” is still active, i.e. the device is switched on and off
automatically at sampling rates of long duration
(see chapter 2).
When memory capacity has been exhausted, MEMO FULL
appears at the display, and an acoustic signal is generated
simultaneously. The signal can be deactivated by pressing
any key.

REM Display

The REM symbol indicates that memory mode operation has
been activated via menu function STORE.

Press the  key if you wish to monitor the measured values
also during the memory process.
The „STORE“ function cannot be started while the „DATA“
function is activated.

12.3 Querying Memory Occupancy – INFO  MEMO/OCCUP

Memory occupancy can be queried from the „1NF0 “ menu.
The main display shows current occupancy as a percentage
between 001 and 100%

12.4 Clearing the Memory – MEMO  CLEAr

This function deletes all measured values from
memory.

This function cannot be performed during memory mode;
bUSY

is displayed instead of CLEAR.

MEMO

12.5 Activating the Default Values

Previously entered changes can be undone, and the default
settings can be reactivated. This may be advisable after the
occurrence of software or hardware errors.

Ð Simultaneously press and hold the FUNC, MAN |AUTO and

DATA|CLEAR keys, and switch the instrument on with the
ON|OFFkey.

Exiting Memory Mode Operation with Menu Functions

Ð Select the StorE menu.
Ð Activate the  key: StOP blinks.
Ð Activate the  key once again: the auxiliary displays are

cleared. Memory mode operation has now been

deactivated.
Ð Press the  key in order to return to the measuring

function.
Ð Memory mode operation can also be exited by switching

the instrument off.

18 GMC-I Messtechnik GmbH

12.6 Transmission Mode Operation with RS 232 Interface

The METRA HIT27 is equipped with an bidirectional infrared
interface for the transmission of measurement data to a PC.
Data are transferred optically through the instrument housing
by means of infrared light to an interface adapter (accessory
USB-HIT), which is attached to the instrument. The adapter’s
USB-HIT-interface allows for the establishment of a
connection to the PC via an interface cable.

The driver to be installed assigns a virtual COM interface to
the instrument. It is not possible to set up a multi-channel
system with this adapter.

Beyond this, commands and parameters can be transmitted
from the PC to the instrument as well. The following functions
can be executed:

• Configuration and read-out of measuring parameters

• Measuring function and measuring range selection

• Start measurements

• Read out measured values

Activating the Interface

The interface is switched on manually as described below for
transmission mode operation. The instrument continuously
transmits measurement data to the PC via the interface
adapter in this operating mode. The interface is activated
automatically by the PC for receiving operation (i.e. the
instrument receives data from the PC).

Starting Transmission with Menu Functions

InFO  SEnd  StArt 

The symbol blinks at the display in order to indicate
interface operation.

Automatic Activation and Deactivation of the Transmission Mode

If the sampling rate is 20 s or longer, the display is switched
off automatically between samples in order to prolong
storage battery or battery service life.
Exception: continuous operation
As soon as an event occurs, the display is automatically
switched back on.

Configuring Interface Parameters

Addr – Address

If several instruments are connected to the PC via interface
adapters, an unique address must be assigned to each
device. Address 1 should be used for the first device,
address 2 for the second etc. If only one multimeter is
utilized, an address between 1 and 14 should be used.
Address 15 is not used for addressing, i.e. the device with
address 15 always responds, regardless of the actual
address.

GMC-I Messtechnik GmbH 19

Main Menus and Submenus

1nf0

mem0

+

send

Set

2x

FUNC ON







Clear

yes no







Selection must blink:
YES: delete memory
no: do not delete



Selection
acknowledge

send

0ff/0n start/st0p







StArt blinks



Activate:

Transmission mode active



StOP blinks



Activate:

no Transmission mode

Current
Status

3.9

batt

V

8 01

mem0 oCCUp

t im e

12:58:08

d a t e

15 08 .02

set

rate





See next page for
more submenus





Storage Battery
Charge Level

Current Time Current Date

↵

 

Delete Memory Menu (see chapter 12.4)

Transmission Mode (see chapter 12.6)

Configure Device Parameters (see chapter 12.1)

Query Information

!

Memory Occupancy
(see chapter 12.3)

t C a l

15 08 .02

Calibration Date

t a d J

15 08 .02

Balancing Date

blinks

does not blink

„

EMPTY

“ appears at the display

 

store store

0ff/0n start/st0p





Memory Mode Menu



StArt blinks



Activate:

Memory mode active



StOP blinks



Activate:

Memory mode inactive

REM is displayed REM is displayed



During memory
mode the memory
cannot be deleted,
bUSY

MEMO

is dis­played instead of
CLEAr.

20 GMC-I Messtechnik GmbH

SEt Submenu for rAtE, Addr, dAtE and tIME Parameters

set

rate

set

addr

set

tIme

set

00:10 :00 rate







Change
Value



Acknowledge
Sampling Rate

00:00:01, 00:00:02, 00:00:05, 00:00:10, 00:00:20, 00:01:00
00:02:00, 00:05:00, 00:10:00, 00:20:00, 01:00:00; 0.50 = 500 ms

Possible Settings

set

15 addr







Change
Value

Set Device Address



Acknowledge
Address

set

13:15:21 t Ime







Change
Valu e

Set Time



Acknowledge
Selection

set

13.08.02 date

Set Date



Select
Position



Change
Valu e



Acknowledge
Selection



Select
Position

Possible Settings (DD:MM:YY, DD=day, MM=month, YY=year)

Possible Settings (hh:mm:ss, hh=hours, mm=minutes, ss=seconds)

Digit
blinks

Possible Settings (see also chapter 12.6): 0 … 15

Set Sampling Rate (see also chapter 12.1)

(hh:mm:ss, h = hours, m = minutes, s = seconds)

Continued from previous page

set

date





GMC-I Messtechnik GmbH 21

13 Characteristic Values

Measuring

Function

V

Resolution at Upper

Measuring Range

Range Limit

4¾ 30000 / 3¾ 3 000

1)

3 V 100 μV2.1MΩ 2.1 MΩ // < 50 pF 0.1 + 10

30 V 1 mV 2.1 MΩ 2.1 MΩ // < 50 pF 0.1 + 5 0.2 + 10 (>500d)

300 V 10 mV 2.1 MΩ 2.1 MΩ // < 50 pF 0.1 + 5 0.2 + 10 (>500d)

Input Impedance

DC AC

6)

600 V 100 mV 2.1 MΩ 2.1 MΩ // < 50 pF 0.1 + 5 0.2 + 10 (>500d)

Meas. current approx.

mΩ@1A

(4 L)

Open-circuit voltage

3mΩ 0.001 mΩ 3.5 … 4 V 1 A

300 mΩ 0.01 mΩ 3.5 … 4 V 1 A

30 mΩ 0.01 mΩ 3.5 … 4 V 200 mA

mΩ

(4 L)

300 mΩ 0.01 mΩ 3.5 … 4 V 200 mA

3 Ω 0.1 mΩ 3.5 … 4 V 20 mA

30 Ω 1mΩ 3.5 … 4 V 20 mA

300 Ω 10 mΩ 3.5 … 4 V 1 mA 0.1 + 10

3kΩ 100 mΩ 3.5 … 4 V 100 μA0.1+5

Ω

(2 L)

30 kΩ 1 Ω 3.5 … 4 V 20 μA0.1+5

300 kΩ 10 Ω 3.5 … 4 V 20 μA0.1+5

3MΩ 100 Ω 3.5 … 4 V 10 μA0.1+5

30 MΩ 1kΩ 3.5 … 4 V 10 μA1.5+10

300 Ω 0.1 Ω 3V 1mA 1+5

3V 0.1mV 3V 1mA 1+5

Test Voltage Measuring Current

MΩ@

...V

Hz

30 MΩ 0.01 MΩ 50/100/250/500 V

3000MΩ

10)

1MΩ 50/100/250/500 V 3 + 10

300 Hz 0.01 Hz

3kHz 0.1 Hz

Temperature

Sensor

9)

Pt 100

Measuring Range Resolution

–200.0 … + 100.0 °C

< 1.5 mA

2)

f

min

1 Hz 0.05 + 5

Intrinsic Error at Max. Resolution under Reference Conditions

+100.0 … + 600.0 °C 0.5 + 5

Pt 1000 –200.0 … + 100.0 °C1 K + 5

°C/°F

+100.0 … + 600.0 °C 0.5 + 5

0.1 °K

Ni 100 – 60.0 … +180.0 °C0.5+ 5
Ni 1000 – 60.0 … +180.0 °C0.5+ 5

1)

Display: 3¾ places in the range of 3 mΩ@1A, 30 mΩ, , MΩ@...V;
A different sampling rate can be selected in the rAtE menu for saving and
transmitting measured values.

2)

Lowest measurable frequency for sinusoidal measuring signals symmetrical to
the zero point

3)

At 0°…+40° C

4)

ZERO is displayed for “zero balancing” function.

5)

Range 3 V~: UE=0.15V

For voltages > 100 V: power limiting of 1.8 · 106V · Hz

6)

20 … 45 … 65 Hz … 1 kHz sine, see influences on page 23.

7)

Pulsating measuring current with interval of T = 1 s

8)

Plus sensor deviation

9)

Temperature value is calculated from the characteristic curve per EN 60751

10)

In the event of extremely high resistances the capacitive influence of the person
performing the measurement and/or the measuring cable may distort the
measured value. Use therefore short or shielded measurement cables.

11)

In the event of an overload, the integrated FF1.6A/1000V fuse is triggered.

Key

rdg. = reading (measured value), R = measuring range, d = digit(s), 2/4 L = 2/4-wire connection

Intrinsic Uncertainty at Max. Resolution

under Reference Conditions

±(...% rdg. + ... d) ±(...% rdg. + ... d)

DC AC

7)

7)

7)

±(...% rdg. + ... d)

1+10

0.5 + 10

0.5 + 10

0.25 + 10

2+10

±(...% rdg. + ... d)

±(...% rdg. + ... d)

1 K + 5

30 V~: UE=1.5V
300 V~: UE=15V
600 V~: UE=30V

4)

4)

8)

6)

0.2 + 10 (>500d)

4)

5)

. . . 3 V

eff/rms

. . . 30 V

eff/rms

. . . 300 V

eff/rms

. . . 600 V

eff/rms

Overload Capacity

3)

Value Time

600 V

DC
AC

Cont.

RMS

sine

±0.6 V

Cont.30 mΩ 0.001 mΩ 3.5 … 4 V 1 A

11)

±0.6 V

Cont.

11)

4)

600 V

DC
AC

max. 10 s

RMS

sine

600 V

max. 10 s300 MΩ 0.1 MΩ 50/100/250/500 V 2 + 10

DC/AC

600 V AC Cont.

600 V

DC
AC

max. 10 s

RMS

sine

eff/rms

eff/rms
eff/rms

eff/rms

22 GMC-I Messtechnik GmbH

Influencing Quantities and Influence Error

Influencing

Quantity

Temperature

1)

With zero balancing

Influencing

Quantity

Frequency

2)

Specified error valid as of display values of 10% of the measuring range

Influencing

Quantity

Relative

humidity

1)

With zero balancing

Influencing

Quantity

Common

Interference

Volt age

Series Mode
Interference

Volt age

Sphere of

Influence

0 … +21 °C

and

+25…

+40°C

Frequency

> 20 Hz ... 45 Hz

V

> 65 Hz ... 1 kHz

AC

Sphere of

Influence

75%

3 days

instrument off

Interference quantity max. 600 V ~ V DC > 90 dB

Mode

Interference quantity max. 600 V ~

Interference quantity: V∼,
respective nominal value

max. 600 V ~ , 50 Hz, 60 Hz sine

Interference quantity max. 600 V DC V ~ > 60 dB

Measured Quantity /
Measuring Range

V DC 0.1 + 5

V AC 0.5 + 5

mΩ@ 1 A 4L 1 + 5

mΩ@ 200 mA 4L 1 + 5

300 Ω … 300 kΩ 2L 0.2 + 5

3MΩ 2L 0.5 + 5

30 MΩ 2L 1 + 5

Insulation 30 M

Measured Quantity /

Measuring Range

Sphere of Influence

50 Hz, 60 Hz sine

of the measuring range,

Ω …

Hz 0.1 + 5

°C (RTD) 0.5 + 10

Measured

Quantity /

Measuring

Range

3V

up to

600.0 V

All measured

quantities

3 G

Influence Error

1)

± (... % rdg. + d)/10 K

Ω

Influence Error
± (... % rdg. + d)

2 + 10

Influence Error

1)

1 x intrinsic
uncertainty

Measuring

Range

30 V ~ > 80 dB

300 V ~ > 70 dB

600 V ~ > 60 dB

V= > 60dB

Real-Time Clock

Accuracy ±1 minute per month
Temperature Influence 50 ppm/K

2 + 5

Damping

±dB

Reference Conditions

Ambient
temperature +23° C ±2K

Relative humidity, 40 ... 60%
Measured quantity
frequency 45 ... 65 Hz
Measured quantity
waveshape Sinusoidal, deviation between RMS

and rectified value < 0.1%

Storage battery voltage 3.6 V ±0.2 V

Response Time

Response Time (after manual range selection)

Measured Quantity /

Measuring Range

VDC, VAC 1.5s

2)

mΩ@ 1 A 4L 2 s

mΩ 1.5 s

300 Ω ... 3 MΩ 2s

3GΩ ∗ 5s

Continuity < 50 ms

°C Pt100 max. 3 s

>10 Hz 1.5 s

* without parallel capacity

Response Time

for Digital Display

1.5 s

Measured Quantity

Step Function

from 0 to 80%

of upper range limit value

from ∞ to 50%

of upper range limit value

from 0 to 50%

of upper range limit value

Display

LCD panel (65 mm x 30 mm) with display of up to 3
measured values, unit of measure, type of current and
various special functions.
Display / Char. Height 7-segment characters

Main display: 12 mm
Auxiliary displays: 7 mm

Number of places 4¾ places 30999 steps
Overflow display „0. L“ appears
Polarity display “–” sign is displayed if plus pole

is connected to “⊥”

LCD test All display segments available

during operation of the METRA
HIT27 are activated after the
instrument is switched on.

Background illumination METRA HIT 27I only

GMC-I Messtechnik GmbH 23

Power Supply

Storage batteries 3 ea. 1.2 V NiMH storage batteries

(AA size) (≥ 2100 mAh)

Service life with set of 2100 mAh NiMH storage batteries

Measuring
Function

V, Hz, Ω, , °C70 30
mΩ@1A 700 3
mΩ@200mA 260 8
mΩ@20mA 85 24

MΩ@ ... V / 1 MΩ100 21

Standby (MEM + clock)

Current
[mA] / 3.6 V

0.15 approx. 1 year

Service Life [h]

Additional consumption for:

Interface operation 0.5 mA
LCD illumination 25 mA at 3.6 V

If voltage drops below 2.7 V, the
instrument is switched off
automatically.

Storage battery test “ ” is displayed automatically if

storage battery voltage drops to
below approx. 3.3 V
(at mΩ@1A < 3.1 V).

Storage battery charging With NA HIT 2x (Z218H) mains power

battery charger; e.g. set of storage
batteries 2100 mAh: recharging
time 20 h
or
With external NiMH battery quick
charger Z206D:

recharging time

approx. 2 hours

Fuses

Fusible links for all
mΩ measuring ranges FF (UR) 1.6 A/1000 V AC/DC,

6.3 mm x 32 mm;
10 kA switching capacity at
1000 V AC/DC

and ohmic load

Acoustic signal For display > 610 V in 600 V range

(intermittent tone, 250 ms on/off)

Electrical Safety

Safety class II per IEC/EN 61010-1:2001

/VDE 0411-1:2002
measurement category II
Operating voltage 600 V
Fouling factor 2
Test voltage 3.5 kV~ per IEC/EN 61010-1:2001/

VDE 0411-1:2002

Electromagnetic Compatibility (EMC)

Interference emission EN 61 326-1:2006 class B
Interference immunity

EN 61326-1:2006
EN 61326-2-1:2006

Data Interface

Data transmission bidirectional, optical via infrared

light through the housing
(read data and configure
parameters)

With interface adapter as accessory

BD232 IR to RS 232C, serial, per

DIN 19241, cascadable for
multi-channel operation

USB-HIT IR to USB 1.1/USB 2.0,

single-channel operation

baud rate (MM ↔ PC) 9600 baud

Ambient Conditions

Accuracy range 0° C ... +40° C
Operating temperature −10° C ... +50° C
Storage temperature − 25° C ... + 70° C (w/o storage

batteries)

Relative humidity 45% ... 75%,

no condensation allowed
Elevation to 2000 m
Deployment Indoors only, except within

specified ambient conditions

Mechanical Design

Protection Housing: IP 54

Connector jacks: IP20

Extract from table on the meaning of IP codes

(1

IP XY

st

digit X)

Protection against

foreign object entry

0 not protected 0 not protected
1 ≥ 50.0 mm

2 ≥ 12.5 mm
3 ≥ 2.5 mm

4 ≥ 1.0 mm
5 dust protected 5 water jets

∅
∅

∅
∅

IP XY

(2nd digit Y)

Protection against the

penetration of water

1 vertically falling drops

vertically falling drops

2

with enclosure tilted 15°

3 spraying water
4 splashing water

Dimensions 84 mm x 195 mm x 35 mm
Weight Approx. 420 gr. with storage

batteries (without GH18 protective

rubber cover)

24 GMC-I Messtechnik GmbH

14 Maintenance

Attention!

!

Warning!
Attention!

!

Attention!

!

(b) (a)

Disconnect the instrument from the measuring circuit
before opening to replace storage batteries, batteries
or fuses!

14.1 Storage Batteries and Batteries

The mains power battery charger may not be
connected if normal batteries have been installed
instead of storage batteries: Danger of explosion!

Removing the Storage Batteries During Periods of Non-Use

The integrated quartz clock draws power from the storage
batteries, even when the instrument is switched off. It is
advisable to remove the storage batteries during long periods
of non-use for this reason (e.g. vacation). This prevents
excessive depletion of the storage batteries, which may result
in damage under unfavorable conditions.

Checking Storage Battery Charge-Level and Condition

The current storage battery charge level can be queried in the
“Info” menu (see chapter 12 on page 17):
FUNC + ON| OFF  InF0  X.X V (bAtt).

Make sure that no storage battery leakage has occurred
before initial start-up, and after long periods of storage.
Continue to inspect the storage batteries for leakage at short,
regular intervals.

– If storage battery leakage has occurred, carefully and

completely clean electrolyte from the instrument with a
damp cloth, and replace the storage batteries before
using the instrument.

– If the “ ” symbol appears at the display, the storage

batteries should be replaced or recharged as soon as
possible. You can continue working with the instrument,
but reduced measuring accuracy may result. Depleted
storage batteries require approximately 20 hours
recharging time with the NA HIT 2x mains power battery
charger. Recharging starts as soon as the instrument is
connected to the mains power battery charger. If the
storage batteries have been excessively depleted, the
instrument cannot be switched on. If this is the case,
leave the (switched on) instrument connected to the
charger for approximately 30 minutes, and then proceed
as described above.

Recharging the Storage Batteries

Use only the NA HIT 2x mains power battery charger (article
number Z218H) from GMC-I Messtechnik GmbH to recharge
the storage batteries in the instrument. This assures operator
safety by means of an extremely well insulated cable, and
safe electrical isolation (nominal secondary ratings: 5 V/
600 mA). The recharging time of the batteries (2,100 mAh) in
the instrument is approx. 20 h.

Before connecting the mains power battery charger to the
recharging jack, make sure that:
– Storage batteries have been installed (not normal batteries)
– The instrument has been disconnected from the measuring

circuit at all poles.

If possible, use the mains power battery charger only for
recharging storage batteries, not for measurements, in order
to avoid influence errors.

Replacing the Storage Batteries

Ð Set the instrument face down onto a flat working surface,

loosen the two screws at the back and lift off the housing
base, starting at the bottom. The housing top and
housing base are held together with the help of snap
hooks at the top front.

Ð Remove the storage batteries from the battery

compartment.

Ð Insert three 1.2 V NiMH storage batteries into the battery

compartment, making sure that the plus and minus poles
match up with the provided polarity symbols.

Ð Important for reassembly: First set the housing base onto

the housing top and align accurately (see photo below).
Then press the two housing halves together, first at the
bottom front (a), and then at the top front (b).

Ð Secure the housing base with the two screws.

The instrument may not be operated if the housing
base has not been properly installed and secured!

Storage battery or battery leakage must be avoided.
Resulting damage is not covered by the guarantee.

GMC-I Messtechnik GmbH 25

14.2 Fuses

Attention!

!

Pb Cd Hg

The fuse is located at the measuring input. When the fuse is
defective, the measurements in the mΩ/Ω/ / ranges are
faulty. The error in the V range amounts to only 10%.

If a fuse should blow, eliminate the cause of overload before
placing the instrument back into service!

Inspecting the Integrated Fuse

Ð Set the rotary switch to the Ω measuring function.
Ð Short circuit the ⊥ and Ω jacks.

Display < 0.2 Ω: fuse OK
Display approx. 200 kΩ: fuse blown or poor contact at
the fuse holder

Replacing the Fuse

Ð Open the instrument as described under “Replacing the

Storage Batteries” .

Ð Remove the blown fuse with the help of an abject such

as a test probe, and replace it with a new fuse.

Table of Allowable Fuses

Type Dimensions Article Number

FF (UR) 1.6 A/1000 V AC/DC (10 kA) 6.3 mm x 32 mm Z109C *

* These fuses are available in packages of ten from our sales offices and

distributors.

Use specified fuses only!
If fuses with other blowing characteristics, other
current ratings or other breaking capacities are used,
the operator is placed in danger, and protective
diodes, resistors and other components may be
damaged.
The use of repaired fuses and short-circuiting the
fuse holder are prohibited.

14.3 Housing

No special maintenance is required for the housing. Keep
outside surfaces clean. Use a slightly dampened cloth for
cleaning. Avoid the use of cleansers, abrasives and solvents.

Disposing of Batteries or Storage Batteries

Dispose of old batteries or storage batteries properly, i.e. at a
designated collection point.

14.4 Device Return and Environmentally Compatible Disposal

The METRA HIT27 is a category 9 product (monitoring and
control instrument) in accordance with ElektroG (German
Electrical and Electronic Device Law). This device is not
subject to the RoHS directive.

We identify our electrical and electronic devices (as
of August 2005) in accordance with WEEE 2002/
96/EG and ElektroG with the symbol shown to the
right per DIN EN 50419 .
These devices may not be disposed with the trash. Please
contact our service department regarding the return of old
devices (address see chapter 17).

If you use batteries or rechargeable batteries in your instrument
or accessories which no longer function properly, they must
be duly disposed of in compliance with the applicable
national regulations.
Batteries or rechargeable batteries may contain harmful
substances or heavy metal such as lead (PB), cadmium (CD)
or mercury (Hg).
They symbol shown to the right indicates that
batteries or rechargeable batteries may not be
disposed of with the trash, but must be delivered to
collection points specially provided for this purpose.

15 Multimeter Messages

The following messages appear at the main display, or the
auxiliary displays as required. See “Symbols used in the
Digital Display” on page 2 for messages displayed at visible
segments.

Message Function Meaning

0. L

leads open

Blinking Unit of Measure

All measuring functions are balanced for each METRA HIT27
at the factory in accordance with the respective technical
specification. If a unit of measure blinks, this indicates that
balancing constants which have been established and saved
to the multimeter are no longer available for the respective
function. If this is the case, measurement results may deviate
from the specification. We recommend sending the
instrument to our Repair and Replacement Parts department
for rebalancing (see chapter 17).

Measuring Indicates overflow
4-wire-mΩ

Measuring current interrupted or fuse defective.

26 GMC-I Messtechnik GmbH

16 Accessories

The BD232 interface adapter (without memory) allows for remote

control of the instrument, as well as transmission of
measurement data from up to six multimeters to a PC (in the
online operating mode with METRAwin
Interface adapter USB-HIT is functionally identical to the BD232
interface adapter, although bidirectional transmission takes
place between the IR and the USB interface in this case.

The driver to be installed assigns a virtual COM interface to
the instrument. It is not possible to set up a multi-channel
system with this adapter.

METRAwin

METRAwin



10 Software



10 software is used to process and display
measurement data at a PC. Sampling can be triggered
manually with an adjustable sampling interval, or in a signal
dependent fashion. Storage of data in ASCII format can be
controlled with two trigger thresholds per measuring channel,
as well as by means of system time.

Hardware Requirements

– a WINDOWS and IBM compatible PC with at least

a 200 MHz Pentium CPU and 64 MB main memory
– VGA monitor with resolution 800 x 600 pixel or higher
– Hard disk with at least 40 MB available memory
–a CD-ROM drive
– Microsoft compatible mouse
– If print-outs are required: a Windows supported printer
–

1 free serial RS232 interface COM1 ... COM8 for utilizing

BD232
or

– 1 USB port for utilizing USB-HIT

Software Requirements

– MS Windows 98, ME, NT4.0, 2000, XP, VISTA (32/64 Bit)

or 7 (32 Bit).

General

The extensive accessories available for our measuring
instruments are checked for compliance with currently valid
safety regulations at regular intervals, and are expanded as
required for new applications. Currently up-to-date
accessories which are suitable for your measuring instrument
are listed at the following web address along with photo,
order number, description and, depending upon the scope of
the respective accessory, data sheet and operating
instructions: www.gossenmetrawatt.com
(→ english → Products → Measuring Technology – Portable →
Multimeters → METRA HIT ... → Accessories).



10).

17 Repair and Replacement Parts Service,

Calibration Center* and Rental Instrument Service

If required please contact:

GMC-I Service GmbH

Service Center

Thomas-Mann-Str. 20
90471 Nuremberg • Germany
Phone [phone]
Fax [phone]
E-Mail [e-mail]
www.gmci-service.com

This address is only valid in Germany.
Please contact our representatives or subsidiaries for service
in other countries.

* Calibration Laboratory for Electrical Quantities

Competent Partner

GMC-I Messtechnik GmbH is certified per
DIN EN ISO 9001:2000.

Our DKD Calibration Laboratory has been accredited in
accordance with DIN EN ISO/IEC 17025:2005 by the
Deutsche Kalibrierdienst (German Calibration Service) under
registration number DKD–K–19701.

Our competence in the field of metrology covers test reports,

Proprietary Calibration Certificates as well as DKD Calibration Cer­tificates.

Our range of services is complemented by our Test Equipment
Management service which is provided free of charge.

An on-site DKD calibration station is an integral part of our ser-
vice department. If any faults are detected during calibration,
our specialists are able to carry out the necessary repairs with
original replacement parts.

Needless to say, in our function as calibration laboratory, we
calibrate all instruments, irrespective of the manufacturer.

DKD Calibration Certificate Reprints

If you order a DKD calibration certificate reprint for your
instrument, please provide us with the reference numbers
indicated in the upper and lower most fields of the calibration
seal. We do not need the instrument’s serial number.

DKD – K – 19701 accredited as per DIN EN ISO/IEC 17025

Accredited quantities: direct voltage, DC value, DC resistance,
alternating voltage, AC value, AC active power, AC apparent power,
DC power, capacitance, frequency and temperature

GMC-I Messtechnik GmbH 27

GMC-I Messtechnik GmbH
Südwestpark 15
90449 Nürnberg•

Germany

Phone [phone]
Fax [phone]
E-Mail

[e-mail]

www.gossenmetrawatt.com

18 Guarantee

The guarantee period for all METRA HIT measuring and
calibration instruments is 3 years after date of shipment.

Calibration is guaranteed for a period of 12 months. The
guarantee covers materials and workmanship. Damages
resulting from use for any other than the intended purpose or
operating errors, as well as any and all consequential
damages, are excluded.

19 Product Support

If required please contact:

GMC-I Messtechnik GmbH

Product Support Hotline

Phone [phone]

Fax [phone]

E-Mail [e-mail]

20 Recalibration

The respective measuring task and the stress to which your
measuring instrument is subjected affect the ageing of the
components and may result in deviations from the
guaranteed accuracy.

If high measuring accuracy is required and the instrument is
frequently used in field applications, combined with transport
stress and great temperature fluctuations, we recommend a
relatively short calibration interval of 1 year. If your measuring
instrument is mainly used in the laboratory and indoors
without being exposed to any major climatic or mechanical
stress, a calibration interval of 2-3 years is usually sufficient.

During recalibration* in an accredited calibration laboratory
(DIN EN ISO/IEC 17025) the deviations of your instrument in
relation to traceable standards are measured and
documented. The deviations determined in the process are
used for correction of the readings during subsequent
application.

We are pleased to perform DKD or factory calibrations for you
in our calibration laboratory. Please visit our website at
www.gossenmetrawatt.com (→ Services → DKD Calibration
Center or → FAQs → Calibration questions and answers).

By having your measuring instrument calibrated regularly, you
fulfill the requirements of a quality management system per
DIN EN ISO 9001.

* Verification of specifications or adjustment services are
not part of the calibration. For products from our factory,
however, any necessary adjustment is frequently performed
and the observance of the relevant specification is confirmed.

Edited in Germany • Subject to change without notice • A pdf version is available on the internet.