Gossen MetraWatt METRA HIT 22S User manual

METRA HIT
22S/M, 23S, 24S, 25S, 26S/M/MIL
Analog Digital Multimeter
with Signalgenerator 3-348-984-03
13/3.06
Operating Instructions

2 GMC-I Gossen-Metrawatt GmbH
1LCDisplay
2MENU/ON|OFF ON / OFF key
Operating Mode Menu :Entry acknowledgment (ENTER or ↵)
3DATA|CLEAR function key for holding, comparing, deleting
measurement value and MIN/MAX
Operating Mode Menu: Individual menu item selection
reverse flux direction,
increase values
4MAN|AUTO Manual measuring range selection key
Operating Mode Menu: Individual menu item selection
forward flux direction,
reduce values
5ESC|FUNC Multifunction key
Operating Mode Menu: Exit menu level and
return to next highest level,
exit parameter entry mode
without storage of values
6Rotary switch for measurement functions
7 Connection jacks with automatic blocking
1
2
3
4
5
6
7
7 **
*
→ chapter 4
→ chapter 2
→ chapter 5
→ chapter 3
→ chapter 7
ff.
→ chapter 3
→ chapter 3
* RMS value measurement with METRA HIT 26S/M/MIL and 25S only
** METRA HIT 22S/M: no current measuring range – with clip only
max.
1000 V ! METRA HIT 23S:
16 A unfused!

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Digital Display Symbols
1 Continuous operation
2 Digital display with display of decimal point and polarity
3 Manual measuring range selection
4 Memory display, “hold measurement value”
5MIN-MAXstorage
6Eventmarking
7 Selected current type
8 Unit of measure
9 Measuring range exceeded
10 Pointer for analog display
11 Analog display scale
12 Violation of negative analog display range
13 Stopwatch activated
14 Zero balancing
15 Memory mode
16 Low battery
17 Acoustic signal on
Meaning of symbols on the instrument
Warning concerning a point of danger
(Attention: observe documentation)
Earth
Continuous, doubled or reinforced insulation
CAT II/III/IV
Measurement category II / III and/or IV device
CSA approval mark
(North American test authority)
Indicates EC conformity
This device may not be disposed 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’.
123 7
8
910
1112
13
16
17
14
15 REM
456
!
Consecutive number
Registration number
Date of calibration (year – month)
German calibration service – calibration laboratory
B0730
01-04
DKD-K-
19701

4 GMC-I Gossen-Metrawatt GmbH
Contents
Page
1 Safety Features and Precautions .................................... 6
2 Initial Start-Up ................................................................. 8
3 Selection of Measurement Functions and
Measuring Ranges ........................................................ 10
3.1 Automatic Measuring Range Selection .............................. 10
3.2 Manual Measuring Range Selection .................................. 10
3.3 Quick Measurements ....................................................... 11
4 LC Display ..................................................................... 11
4.1 Digital Display ................................................................. 11
4.2 Analog Display ................................................................ 11
5 Measurement Value Storage, “DATA Function”
(Hold & Compare) .......................................................... 12
6 Minimum and Maximum Value Storage
“MIN-MAX” with Time Stamp ....................................... 13
7 Voltage Measurement ................................................... 14
7.1 Transient Overvoltages ..................................................... 15
7.2 Voltage Measurements for Greater than 1000 V ................ 15
8 Alternating Voltage Level Measurement (dB) ................ 16
9 Current Measurement with METRA HIT 23/24/25/26 .... 17
9.1 AC Measurement with Current Transformers ..................... 18
9.1.1 mA or A Transformer Output (METRA HIT 23/24/25/26) .... 18
9.1.2 Transformer Output mV/A) ............................................... 19
10 Resistance Measurement .............................................. 20
11 Continuity Testing for Resistance Measurement .......... 20
12 Diode Testing ................................................................ 21
13 Continuity Testing for Diode Tests ................................ 22
14 Signal Generator ........................................................... 22
15 Capacitance Measurement ........................................... 24
16 Frequency Measurement .............................................. 24
17 Temperature Measurement .......................................... 25
18 Event Counting and Zero Crossings .............................. 26
18.1 Event Counting ................................................................ 26
18.2 Count Zero Crossings ...................................................... 27
19 Stopwatch ..................................................................... 27
20 Storing Measurement Values
with the METRA HIT 22M/26M/MIL ............................... 28
20.1 General Parameters ......................................................... 30
20.2 Trigger Functions ............................................................ 31
20.2.1 Trigger Function Parameters ............................................ 32
21 Setting the Measurement Parameters .......................... 38
21.1 Description of Items in the SEt .Menu . ............................ 40

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Page
21.1.1 rAtE – Sampling Rate ..................................................... 40
21.1.2 Menu – Rapid Query ...................................................... 40
21.1.3 tiME – Time and Date .................................................... 40
21.2 Description o Parameters in the inFo Menu ...................... 41
21.3 Default Settings ............................................................... 41
21.4 List of All Parameters ...................................................... 42
22 Data Transmission via RS232 Interface ........................ 43
22.1 Activating the Interface .................................................... 43
22.2 Selecting Interface Parameters ......................................... 44
23 Accessories ................................................................... 45
24 Characteristic Values ................................................. 46
25 Maintenance ................................................................. 54
25.1 Batteries ......................................................................... 54
25.2 Fuses ............................................................................. 56
25.3 Housing .......................................................................... 56
26 Multimeter Messages ................................................... 57
27 Accessories ................................................................... 57
27.1 General ........................................................................... 57
27.2 Characteristic Values of Measuring Cables
(Scope of Supply of Safety Cable Set KS17-2) ................... 57
28 Repair and Replacement Parts Service
DKD Calibration Lab
and Rental Instrument Service ...................................... 58
29 Guarantee ...................................................................... 59
30 Product Support ............................................................ 59
Use for Intended Purpose:
– The multimeter described herein is a portable instrument
which can be held in one hand during measurements.
– Only such measurements are performed as described in
chapters 7 to 19.
– The measuring instrument including measuring cables
and plug-on test probes is only used within the measur-
ing category indicated (refer to page 52 and/or page 53
and to the table on page 6 for the meaning of the mea-
suring categories).
– The limits of the overload capacity may not be exceeded.
Refer to the Characteristic Values on page 48 for the
duration and values of the overload capacity.
– Measurements are only performed within the specified
ambient conditions. Refer to page 53 for the operating
temperature range and relative humidity.
– The measuring instrument is only used in accordance
with the specified protection type (IP code), see page 53.

6 GMC-I Gossen-Metrawatt GmbH
1 Safety Features and Precautions
You have selected an instrument which provides you with a
high level 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 Gossen-Metrawatt GmbH.
The analog digital multimeter 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 (see page 5), safety of the opera-
tor, 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 instru-
ment into service, and that you follow all instructions contained
therein.
For your safety, as well as for the protection of your instru-
ment, the multimeter is equipped with an automatic socket
blocking device. This is coupled to the rotary switch, and
only allows connection to the socket required for the
selected function. It also prevents the switching of the
rotary selector to disallowed functions when a measure-
ment cable is plugged into a socket.
The following special multimeter is not covered by the new safety
standard: METRA HIT 23S.
Measuring Categories and their Meaning per IEC 61010-1
The measurement category and the relevant maximum
rated voltage (e. g. 600 V CAT III) which are shown on the
instrument casing apply to your measuring instrument.
CAT Definition
I
Measurements in electrical circuits not directly connected to
the mains system:
e. g. power systems in motor vehicles or aeroplanes, batteries ...
II
Measurements in electrical circuits directly connected to the
low-voltage system:
via plug, e.g. in households, offices, laboratories ...
III
Measurements in facility installations:
stationary consumers, distributor connections, devices
attached to a distributor
IV Measurements at the source of low-voltage installations:
Meters, main terminal, primary overcurrent protection devices

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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 may
occur (effective value).
• Avoid working alone when taking measurements which
involve contact hazards. Be certain that a second person
is present.
•The maximum allowable voltage
between the jacks (7) and earth
is 1000 V for category III and 600 V for category IV
Exception METRA HIT 23S: 1000 V Categorie II only.
•Nominal line voltage may not exceed the following values:
– Between conductor and neutral: 600 V
– 690 V between phase conductors in 4-wire 3-phase
systems
– 1000 V between phase conductors in 3-wire 3-phase
systems.
• Be prepared for the occurrence of unexpected voltages
at devices under test (e.g. defective devices). For exam-
ple, capacitors can be dangerously charged.
• Make certain that the measurement cables are in flaw-
less condition, e.g. no damage to insulation, no interrup-
tions in cables or plugs etc.
• 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 are not
allowable.
• Be absolutely certain that the measuring ranges are not
overloaded beyond their allowable capacities. Limit val-
ues can be found in the table “Measuring Ranges” in
chapter 24 “Characteristic Values”.
• All current ranges are equipped with fuses, except for
METRA HIT 23S (which has no 16 A fuse in the 3 und
16 A measuring ranges).The maximum permissible
voltage of the measuring circuit (= nominal voltage of the
fuse) is 1000 V AC/DC in the „mA“ and „A“ ranges.

8 GMC-I Gossen-Metrawatt GmbH
•METRA HIT 23S has been optimized for measurements in
secondary current transformer circuits and has no inte-
grated fuse in the 16 A current circuit for reducing hazards in
the event of short circuits on the primary side.
In circuits with voltages involving contact hazards
METRA HIT 23S may only be used if the current circuit is
protected by a fuse or a circuit breaker with 20 A.
METRA HIT 23S must not be used for current measure-
ments in the 16 A current circuit (rotary swith „A“) in
application category III and IV.
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 for repair, replacement of parts
or balancing. If repair or balancing of a live, open instru-
ment is required, this may only be carried out by trained
personnel who are familiar with the dangers involved.
Errors 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 demonstrates visible damage,
• if the instrument no longer functions,
• after a long period of storage under unfavorable condi-
tions, (e.g. high humidity, dust or excessive temperature),
see "Ambient Conditions", page 53.
2 Initial Start-Up
Batteries
Please refer to chapter 25.1 regarding correct batteries
installation!
Attention!
!
Before opening the instrument, disconnect it from
the measuring circuit.
Switching the Instrument On Manually
➭Press the ON key until the display disappears.
Activation is acknowledged with a brief acoustic signal.
As long as the key remains pressed, all segments of the
liquid crystal display (LCD) are active. The LCD is shown
on page 3.
After the key is released, the instrument is ready for
operation.
METRA HIT 22S: Press key until LCD appears.

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Switching the Instrument On via PC (except for METRA HIT 22S)
After transmission of the first data block from the PC, the
multimeter is switched on. See also chapter 22, page 43.
Automatic Start-Up
The multimeter is switched on automatically in the transmit
or data storage mode.
Note!
☞Electrical discharge and high frequency interference
can cause incorrect displays, and may block the
measuring sequence. To reset, switch the instru-
ment off, and then back on. If this procedure is
unsuccessful, briefly disconnect the battery from the
contact terminals.
Setting Time and Date
See chapter 21.1.3, page 40.
Switching the Instrument Off Manually
➭Press and hold the ON key, until the display is deacti-
vated.
Deactivation of the instrument is acknowledged by two
brief acoustic signals.
Automatic Shut-Off
Your instrument shuts itself off automatically, if the mea-
surement value remains constant for a long period of time
(maximum measurement value fluctuation: approx. 0.8%
of the measuring range per minute or 1 °C or 1 °F per
minute), and if none of the keys or the rotary switch are
activated for a period of 10 minutes. Deactivation of the
instrument is acknowledged by a brief acoustic signal.
Exceptions are as follows:
Event counting, stopwatch, transmit or memory mode and
continuous operation.
Disabling Automatic Shut-Off
The instrument can also be switched to
“CONTINUOUS ON”.
➭Simultaneously press the ON key and the multifunction
key ESC|FUNC when switching the instrument on. The
“CONTINUOUS ON” function is indicated at the LCD
with the symbol.

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3 Selection of Measurement Functions and
Measuring Ranges
The rotary switch is coupled to the automatic socket
blocking device, which makes two jacks available for each
function. Before switching to the “mA” or “A” functions, or
out off the “mA” or “A” functions, be certain that the plug
has been removed from the corresponding jack. The
socket blocking device prevents inadvertent switching to
disallowed functions when a plug connection exists.
3.1 Automatic Measuring Range Selection
The multimeter is equipped with automatic measuring
range selection for all measuring ranges, except for tem-
perature measurement, as well as diode and continuity
testing. This automatic feature is active as soon as the
instrument is switched on. The instrument automatically
selects the measuring range which provides optimum res-
olution for the measured quantity.
The previously selected voltage measuring range remains
active after switching the instrument to frequency mea-
surement or events counting.
The instrument is automatically switched to the next high-
est or next lowest measuring range for the following mea-
sured quantities:
1) 280 digits apply when switching from 100 kHz to 3 kHz
3.2 Manual Measuring Range Selection
The automatic measuring range feature can be deactivated
and the ranges can be manually selected and prescribed
according to the following table.
The manual mode is deactivated by pressing and holding
the MAN|AUTO key (approx. 1s), by activating the rotary
switch or by switching the instrument off and back on again.
Measuring Range Reso-
lution
Switching to the
Next Highest
Range
at ±(... D + 1 D)
Switching to the Next
Lowest Range 1)
at ±(... D –1 D)
V,V,A,
mA , A , Ω, 30
mF, Hz
4 ¾ 31 000 2 800
3 nF ... 3 mF 3 ¾ 3 100 280
⇓
MAN/
AUTO
Function
Acknowledge
Dis-
play
Acoust.
Signal
Brief Manual Mode Active:
selected measuring range is fixed MAN 1 x
Brief
Switching Sequence for:
V: 300 mV →3V→30 V →300 V →1000 V →
300 mV → ...
dB: same switching sequence as for V
mA : 300 μA→3mA→30 mA →300 mA →300 μA ...
A: 3A→10 A → 3 A ...
Ω:30MΩ→300 Ω→ 3kΩ→30 kΩ→ 300kΩ→
3MΩ→30 MΩ...
F: 3nF→30 nF →300 nF →3 μF→30 μF→
300 μF→3000 μF→30000 μF→3 nF ...
Hz: 300 Hz →3kHz→100 kHz →300 Hz ...
MAN 1 x
Long Return to Automatic Range Selection — 2 x

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3.3 Quick Measurements
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:
•bymanual measuring range selection, i. e. by selecting
the measuring range with the best resolution, see
chapter 3.2.
or
•viaDATA 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 measure-
ments.
4LCDisplay
4.1 Digital Display
The measurement value appears at the digital display with
correct decimal place and plus or minus sign. The selected
unit of measure and the type of current are displayed as
well. A minus sign appears in front of the numeric value for
the measurement of zero-frequency quantities if the posi-
tive pole of the measured quantity has been connected to
the “⊥” input. If the measuring range upper limit is
exceeded for the following measured quantities, “OL”
(overload) appears at the display:
V DC, I DC, Ω, Hz, F,
V (AC, AC+DC), I (AC+DC), dB (V), 30 mF: 30999 digits
3 nF ... 3 mF 3099 digits
The digital display is refreshed at various intervals depend-
ing upon the measured quantity (see Display Update on
page 51).
4.2 Analog Display
The analog display with simulated pointer demonstrates
the dynamic characteristics of a moving coil mechanism
and is refreshed 20 times per second. The analog display
is especially advantageous for the observation of measure-
ment value fluctuation, as well as during balancing.
The analog display includes its own polarity indicator. The
analog scale has a negative range including 5 scale mark-
ings which allows for the precise observation of measure-
ment value fluctuations which drop below zero. If the mea-
surement value exceeds the display range, the triangle
appears at the left hand side of the display and polarity is
reversed at the analog display after approx. 0.7 s. If the
measuring range is exceeded (> 30999 digits, within a
range of F : > 3099), the triangle appears at the right hand
side of the display.
Scaling for the analog display is adjusted automatically,
which is quite helpful for manual measuring range selec-
tion.

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5 Measurement Value Storage, “DATA Function”
(Hold & Compare)
Measurement values can be automatically “frozen” with the
DATA (hold) function. This can be especially useful when
your full attention is required for contacting the measuring
point with the test probes. After the measurement value
has been acquired and the appropriate “condition” as
shown in the table below has been fulfilled, the measure-
ment value is frozen at the digital display and an acoustic
signal is generated. The test probes can now be removed
from the measuring point and the measurement value can
be read from the digital display. If the measurement value is
less than the lower limit value shown in the table, the
instrument is reactivated and stores a new value.
Measurement Value Comparison (DATA Compare)
If the newly stored value deviates less than 100 digits from
the previous value, the acoustic signal sounds twice. If it
deviates more than 100 digits, only a brief acoustic signal
sounds.
1) Reactivation if actual value falls below prescribed limit value
2) Relative to alternating voltage values
3) Acoustic signal sounds twice when measurement value is first
stored as reference value. Only sounds twice for subsequent hold
function if the current hold value deviates less than 100 digits
from the first hold value.
4) Exception: 10% at 300 Ωor 3 nF
The DATA function has no effect on the analog display,
which continues to indicate the current measurement
value. However, as long the digital display remains
“frozen”, the decimal place can not be shifted.
The measuring ranges ought not to be changed manually
as long as the DATA function is active.
The DATA function is deactivated by pressing and holding
Function
DATA
⇓
DATA
Condition Reaction at Instrument
Measur-
ing
Function
Mea-
sured
Value
Display Acous-
tic
Signal
Meas.
Value
Digital
DATA
Switch on brief blinks 1 x
Store
(stabilized
measured
value)
V, dB 2), A
F, H z
> 3,3%
of range 4) is dis-
played
is dis-
played
1 x
2 x 3)
ΩOL4)
Reactivate 1)
V, dB 2), A
F, H z < 3,3%
of range 4) stored
meas.
value
blinks
ΩOL4)
Changeover
to MIN/MAX
function
brief see table chapter 6
Cancel long is
deleted
is
deleted 2 x

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(approx. 1 s) DATA|CLEAR key, by activating the rotary switch
or by switching the instrument off and back on again.
6 Minimum and Maximum Value Storage
“MIN-MAX” with Time Stamp
Minimum and maximum measurement values which occur
at the measuring instrument’s input after activation of the
MIN/MAX function can be “frozen”. The most important
application for this function is the determination of mini-
mum and maximum values during long-term observation
of measurement values.
The “MIN/MAX” function can be activated for all measuring
ranges except for counter, events and stopwatch, nor is
time stamping available for frequency and capacitance
measurements.
The MIN/MAX function has no effect on the analog display,
which continues to indicate the current measurement
value.
Apply the measured quantity to the instrument’s measure-
ment input and select the measuring range before activat-
ing the MIN/MAX function.
After the function has been activated, measuring ranges
can only be selected manually which causes deletion of the
stored MIN-MAX values.
MIN and MAX values are deleted by pressing and holding
the DATA|CLEAR key (approx. 1 s), by activating the rotary
switch or by switching the instrument off and back on
again.
Function
MIN/MAX
⇓
DATA/
CLEAR
MIN and MAX
Measurement
Values/
Time of
Measurement
Reaction at Instrument
Display
Acoust
Signal
Display Digital MIN
MAX
1.
Switch on
and Store
2 x brief are stored
Current
Measurement
Value
MIN and
MAX
blink
2 x
2.
Store and
display
brief
Storage continues
in background,
new MIN and MAX
values and
integration peri-
ods are displayed.
Stored MIN
Value MIN 1 x
brief Elapsed Time to
MIN Value
Storage
MIN and
t1 x
brief MIN and
t1 x
brief Stored MAX
Value MAX 1 x
brief Elapsed Time to
MAX Value
Storage
MAX
and t 1 x
brief MAX
and t 1 x
3.
Return to
1.
brief
same as 1.,
stored values are
not deleted
same as 1. same as
1. 1 x
Cancel long are deleted is deleted is
deleted 2 x

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7 Voltage Measurement
METRA HIT 26S/M/MIL V ACTRMS + V(AC+DC)TRMS
METRA HIT 25S V ACTRMS
METRA HIT 22S/M, 23S, 24S V AC mean value rectification
➭Depending upon the voltage to be measured, set the
rotary switch to V~, V orV .
➭Connect the measurement cables as shown.
The “⊥” jack should be grounded.
Note!
☞In the 1000 V range, an intermittent acoustic
signal sounds alarm if the measurement value
exceeds the measuring range upper limit value.
Attention!
!
Make absolutely certain that neither of the current
ranges (“mA” or “A”) is active when the multimeter is
connected for voltage measurements! If the fuse trip
limits are exceeded due to operator error, both the
operator and the instrument are in danger!
Zero Balancing in the 300 mV Measuring Range
➭Select the 300 mV measuring range.
➭Connect the measurement cables to the instrument, and
connect the free cable ends to one another.
➭Briefly press the multifunction key.
The instrument acknowledges zero balancing with an
acoustic signal and “000.00” (±1 digit) and the “ZERO”
symbol appears at the LCD. The voltage which was dis-
played at the moment the key was activated serves as a
reference value (max. ±2000 digits). It is automatically sub-
tracted from subsequently measured values.
➭Zero balancing can be deleted:
– by pressing and holding the ESC|FUNC multifunction key,
after which deletion is acknowledged with a twice
repeated acoustic signal,
– by switching the instrument off.
1000V
V
F°C
– (+)
~
+ (–)
~

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7.1 Transient Overvoltages
METRA HIT 22/23/24/25/26 multimeters are protected
against transient overvoltages in the voltage measuring
range up to 8 kV with a halftime value for front time of
1.2/50 μs. Due to the fact that overvoltages of greater
duration can be expected when performing measure-
ments, for example at transformers or motors,we recom-
mend our KS30 measuring adapter for such cases. It pro-
vides for protection against transient overvoltages of up to
6 kV with a halftime value for front time of 10/1000 μs.
Continuous loading capability is equal to 1200 Veff. Addi-
tional influence error due to use of the
KS30 measuring adapter amounts to approximately –2%.
7.2 Voltage Measurements for Greater than 1000 V
Voltages of greater than 1000 V can be measured with a
high-voltage probe, for example the HV31) or the HV302)
from GMC-I Gossen-Metrawatt GmbH. The earthing termi-
nal must be connected to ground for measurements of this
type. Observe all required safety precautions!
1) HV3: 3 kV
2) HV30: 30 kV, for (DC) voltages only
Voltage Measurements for Greater than 1000 V
with the HV3 High-Voltage Probe
black
black
red
x1000 x100
1000V
V
F
° C

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8 Alternating Voltage Level Measurement (dB)
The voltage level measurement is
used for determining the overall
damping or gain of a transmission
system (shown here as a two-port
network).
Voltage level [dB]
with V1= VREF (reference level rEFvALUE)
result > 1: gain; result < 1: damping
➭Set the rotary switch to V .
➭Briefly press the ESC|FUNC multifunction key.
The level measurement function is now active. The mea-
surement value is calculated from the effective value of the
alternating voltage component dependent upon the mea-
suring range (300 mV ... 1000 V), and appears at the digital
display. The present alternating voltage value (U2) is indi-
cated at the analog scale.
The default setting for the reference level corresponds to a
value of 0 dB = 0.775 V (1 mW at 600 Ω). This value (UREF)
can be changed in the “Setup” menu:
SEt ↵  rEFdB ↵XXXXX dB ↵.
➭Frequency measurement can be activated by briefly
pressing the multifunction key once again.
➭If the ESC|FUNC mutlifunction key is pressed and held
(approx. 1 s), the instrument returns to voltage measure-
ment.
Note!
☞No matching resistors have been installed into the
instrument. It takes measurements with a high input
resistance of 5 MΩ.
Input resistance for voltage measurement is listed
under technical data. In order to perform correct
measurements at non-terminated devices under
test, a matching resistor must be connected to the
terminals. Observe power dissipation at the match-
ing resistor!
dB Ranges
For inherent deviations (details on errors and/or tolerances)
the values of the voltage measurement ranges apply (see
page 48), whereas these data are only valid as from 10%
of the respective measuring range.
Measuring Ranges Display Range at
Reference Voltage, UREF = 0,775 V Resolution
300mV
3V
30V
300V
1000V
– 48 dB ... – 8 dB
– 28 dB ... + 12dB
– 8 dB ... + 32 dB
+ 2 dB ... + 52 dB
+ 22 dB ... + 63 dB
0.01 dB
0.01 dB
0.01 dB
0.01 dB
0.01 dB
0.01 dB
V1V2
20
V2
V1
------log⋅=

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9 Current Measurement with METRA HIT 23/24/25/26
METRA HIT 25S/26S/M/MIL A (AC+DC)TRMS
METRA HIT 23S/24S A AC mean value rectification
Attention!
!
METRA HIT 23S: The instrument is intended for per-
forming measurements in the transducer sector of
energy measuring technology. The 3 A and 16 A
measuring ranges covered by METRA HIT 23S are
not fuse-protected!
➭First switch off the power supply to the measuring circuit
or the load component and discharge any capacitors
which might be present.
➭Select range A with the rotary switch for currents
> 300 mA, or range mA for currents < 300 mA.
Switch to the measuring range A first, for the measurement
of currents of an unknown quantity.
➭Select the respective current type which corresponds to
the measured quantity by briefly pressing the ESC|FUNC
multifunction key. Each activation of the key causes alter-
nate switching between DC1) and AC or (DC +
AC)TRMS2), as well as acknowledgement by means of an
acoustic signal. The symbols DC, AC or (DC+AC)TRMS
indicate the selected voltage type at the LC display.
After the range has been selected with the rotary switch,
the DC current mode is always active.
➭Securely connect the instrument to the load component
in series as shown (without matching resistor).
1) METRA HIT 23S/24S
2) METRA HIT 25/26
AmA
10A300mA
AmA
10A300mA
– (+) / ~
+ (–) / ~
. . . 300 mA
. . . 10 A
– (+) / ~
+ (–) / ~

18 GMC-I Gossen-Metrawatt GmbH
Current Measurement Tips:
• The measuring circuit must be mechanically stable and
protected against unintentional interruption. Conductor
cross sections and connection points must be substan-
tial enough to avoid excessive overheating.
• In the 300 mA and 10 A measuring ranges an intermit-
tent acoustic signal warns you, if the measurement value
has exceeded the measuring range upper limit value.
• Current ranges up to 300 mA are protected with a
FF (UR) 1.6 A/1000 V AC/DC fuse in combination with
power diodes up to a short-circuit current of 25 A. The
breaking capacity of the fuse is equal to 10 kA at a nom-
inal voltage of 1000 V AC/DC with resistive load.
• Measuring ranges up to 10 A are protected with a
FF (UR) 16 A/1000 V AC/DC fuse. The breaking capacity
of the fuse is equal to 30 kA at a nominal voltage of
1000 V AC/DC with resistive load.
• If the fuse for the active current measuring range is
defective, “FUSE” appears at the digital display and an
acoustic signal sounds simultaneously.
• If a fuse blows, eliminate the cause of the overload
before placing the instrument back into operation!
• Fuse replacement is described in
chapter 25.2, page 56.
9.1 AC Measurement with Current Transformers
9.1.1 mA or A Transformer Output
(METRA HIT 23/24/25/26)
If a (clip-on) current transformer is connected to the multi-
meter (mA or A input), all current indicators are displayed in
accordance with the selected transformation ratio. How-
ever, the current transformer must have a transformation
ratio of either 1000:1 or 10000:1, and the transformation
ratio must be selected in the following menu.
Current Clip Setup Menu:
SEt ↵ CLIP ↵oFF  1000  10000 ↵.
If you have selected 1000 or 10000 in the menu, you can
switch back and forth between two different current dis-
plays with the help of the ESC|FUNC key:
The selected transformation ratio is only taken into consid-
eration if a preceding c: is entered (c for clip).
Attention!
!
If current transformers are used at the secondary
side in an open condition, e.g. due to defective or
non-connected power cables, a blown device fuse
or incorrect connection, dangerously high voltages
can occur at the terminals. For this reason, check to
see if the measuring instrument’s current path and
transformer’s secondary winding, which is con-

GMC-I Gossen-Metrawatt GmbH 19
GB
nected to the instrument, complete a closed current
circuit, and connect the transformer to the ⊥and
mA or A jacks.
Note!
☞After measurement with the current clip has been com-
pleted, “oFF” should be selected in the setup menu.
Without taking into consideration the transformation
ratio you can only take measurements in the (mA/
A) DC range.
The maximum allowable operating voltage is equal to the
rated voltage of the current transformer. When reading the
measurement value, consider any additional display error
caused by the clip-on current transformer.
9.1.2 Transformer Output mV/A)
METRA HIT 22...26
The secondary terminal at transformers with voltage out-
puts must be connected to the ⊥and V~ jacks.
METRA HIT 22S/M
Transformers of the type WZ12B/C are connected to the
Ajack. After pressing the ESC|FUNC button the measur-
ing results are displayed with the exact decimal places pro-
vided the transformation ratio (CLIP) has been properly set.
Current clip setup menue:
SEt ↵ CLIP ↵1 (mV) : 1 mA/10 mA/1 A  ↵.
AmA
10A300mA1000V
V
F°C
– (+) / ~
+ (–) / ~
…300 mA
(…10 A)
9.1.2 9.1.1

20 GMC-I Gossen-Metrawatt GmbH
10 Resistance Measurement
➭Be certain that the device under test is voltage-free.
Extraneous voltages distort the measurement results!
➭Set the rotary switch to „Ω“.
➭Connect the DUT as shown.
Zero Balancing in the 300 Ωand 3 kΩ Measuring Ranges
Cable and transition resistance can be eliminated with zero
balancing for measurements of small resistance values in
the in 300 Ωand 3 kΩranges :
➭Connect the measurement cables to the instrument, and
connect the free cable ends to one another.
➭Briefly press the ESC|FUNC multifunction key.
The instrument acknowledges zero balancing with an
acoustic signal and “000.00 Ω” and the “ZERO” symbol
appears at the LCD. The resistance which was mea-
sured at the moment the key was activated serves as a
reference value (max. 2000 digits). It is automatically
subtracted from subsequently measured values.
➭Zero balancing can be deleted:
– by pressing and holding the ESC|FUNC multifunction key,
after which deletion is acknowledged with a twice
repeated acoustic signal,
– by switching the instrument off.
See chapter 11 for continuity testing.
11 Continuity Testing for Resistance Measurement
The instrument generates a continuous tone in a range
from0toapprox.10Ω if the “acoustic signal” function is
active, however only in the 0 to 310 Ω measuring range.
The limit value can be adjusted in the “Setup” menu:
SEt ↵ trig ↵ cont i ↵ cont i Ω↵XXX Ω ↵.
1000V
V
F°C
Rx
Voltage Drop