Gossen MetraWatt METRA HIT 27EX User manual

Operating Instructions
METRA HIT⏐27EX
Milliohmmeter for deployment
in potentially explosive atmospheres 3-349-336-49
9/8.16

2 GMC-I Messtechnik GmbH
1Display(LCD)
2ON|OFFkey for ON / OFF
(ON short: instrument ON → ON short: background illumination ON →
→
OFF short: background illumination OFF → OFF long: instrument OFF)
Operating mode menu: open submenus / acknowledge entries
3 DATA|CLEAR key for the functions save/delete measured value
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
5MENU/ESC
Operating mode menu: Exit menu level and
return to a higher level,
exit parameters configuration
without saving data
6LEDOK blinks: valid measured value
7LEDERROR blinks: incorrect connection
8 Connector jacks *
1
2
6
4
5
8
Measurement only on
voltage-free objects!
→ chapter 5
→ chapter 3
→ chapter 4
→ chapter 7.2
→ chapter 7.3
→ chapter 7
7→ chapter 7.3
3→ chapter 6

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Symbols used in the Digital Display
1 Main display with decimal point
2 Auxiliary displays
3 : Milliohmmeter in continuous operation,
ON blinks at transmission frequency in transmission mode
4 REM: Memory mode operation, disappears after communication
via the interface is ended by means of key or switch
operation
5 ZERO: Zero balancing
6 MAN: Manual measuring range selection
7 Unit of measure (if blinking, refer to chapter 11 on page 33)
8:Low battery voltage, replace batteries
* I- Measurement input
U- Sense – for 4-wire measurement
U+ Sense + for 4-wire measurement
I+ mΩ; Ωmeasurement input
1
2
8
64 53
7

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Contents Page
1 Application .............................................................. 5
2 Safety Features and Precautions ............................ 5
3 Initial Start-Up ......................................................... 8
4 Selecting Measuring Functions and Measuring Ranges .10
4.1 Automatic Measuring Range Selection ................................10
4.2 Manual Measuring Range Selection ....................................10
4.3 Quick Measurements ......................................................... 10
5 Triple Digital Display ............................................. 11
6 Measured Value Storage ....................................... 12
6.1 Measured Value Storage – Key Function “DATA” .................12
7 Milliohm Measurement (4-Pole-Measurement) .... 14
7.1 Compensation of Cable Resistance ..................................... 14
7.1.1 Measurement with Kelvin Probe KC27 ................................14
7.2 Thermovoltage Compensation ............................................. 15
7.3 Milliohm Measurement with ≤100 mA DC [mΩ] ................. 16
8 Using the Menus – from the Initial InFO Menu to
Operating and Measuring Parameters .................. 17
8.1 Sampling rAtE ........................................................ 17
8.2 Saving Measured Values .................................................... 18
8.2.1 Memory Mode – DATA Key Function (see also chapter 6.1) ..18
8.2.2 Memory Mode Operation – STORE Menu Function ............... 19
8.3 Querying Memory Occupancy – INFO MEMO/OCCUP ....... 19
8.4 Clearing the Memory – MEMO CLEAr .............................20
8.5 Activating the Default Values ..............................................20
8.6 Transmission Mode Operation with RS 232 or USB Interface 21
9 Characteristic Values ........................................... 26
10 Maintenance ......................................................... 30
10.1 Batteries ............................................................................30
10.2 Fuses ................................................................................31
10.3 Housing and Display ........................................................... 32
10.4 Collection of Used Instruments and Environmentally
Compatible Disposal ........................................................... 33
11 System Messages ................................................. 33
12 Repair and Replacement Parts Service,
Calibration Center and Rental Instrument Service 34
13 Manufacturer’s Guarantee .................................... 35
14 Product Support .................................................... 35
15 Recalibration ......................................................... 36

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1 Application
METRA HIT⏐27EX is a milliohmmeter with 4-pole measure-
ment, which is designed for deployment in potentially
explosive environment.
In accordance with directive 2014/34/EU the device is
approved for being used in explosive, gaseous atmo-
spheres (IIA T4) with ambient temperatures between –
10 °C and +50 °C.
The device conforms to the following standards:
– EN 60079-0:2012 + A11:2013
– EN 60079-11:2012
It bears CE certification number, type INERIS 05ATEX0040,
which has been conferred by the Ineris certification authority.
2 Safety Features and Precautions
You have selected an instrument which provides you with
high levels of safety.
This instrument fulfills the requirements of the applicable
EU guidelines and national regulations. We confirm this
with the CE marking. The relevant declaration of conformity
can be obtained from GMC-I Messtechnik GmbH.
The METRA HIT⏐27EX is manufactured and tested in
accordance with safety regulations IEC 61010–1:2010 /
EN 61010–1:2011/VDE 0411–1:2011/EN 60079-0:2009 and
EN 60079-0:2012/EN 60079-11:2012. 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 instru-
ment into service, and that you follow all instructions contained
therein.
Use for Intended Purpose:
– The milliohmmeter described herein is a portable
instrument which can be held in one hand during mea-
surements.
– The milliohmmeter may only be operated with the
included or with type-tested batteries, as specified in
the Characteristic Values.
– The milliohmmeter may only be operated with closed
housing. The instrument must be removed from the
potentially explosive environment before opening the
housing to replace batteries or fuses.
– Only the type-tested fuses specified in the Characteris-
tic Values may be used.
– The milliohmmeter may only be used to perform such
measurements as described in chapter 7.
– The limits of the overload capacity may not be
exceeded. Refer to the “Characteristic Values” on
page 26 for overload values and overload duration.

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– Measurements may only be performed within the indi-
cated ambient conditions. See page 29 for operating
temperature range and relative humidity.
– The instrument may not be used in a dusty atmo-
sphere.
– No maintenance operation may be performed in
potentially explosive atmospheres (cleaning, replace-
ment of batteries, opening the device, etc.)
Observe the following safety precautions:
•Type-tested Housing
The milliohmmeter may not be operated with open
housing.
In a potentially explosive atmosphere the housing may
not be opened. In this case, there is no protection
against explosions.
•Type-tested Batteries
Use the included or other type-tested batteries with
identical technical features only, see Characteristic Val-
ues.
Before use, please make sure that the housing cover is
closed. There is no protection against explosions when
the housing is open.
Batteries may only be replaced outside the potentially
explosive environment. No spare batteries may be
brought into the potentially explosive environment.
•Operation by qualified electricians
The instrument may only be operated by persons who
are capable of recognizing shock hazards and taking
the appropriate safety precautions. Shock hazards
exist anywhere, where voltages of greater than 33 V
(RMS) may occur.
•Shock Hazards
Avoid working alone when taking measurements
which involve shock hazards. Be certain that a second
person is present.
•Measurement Cables
Make sure that all measurement cables are in faultless
condition, e.g. undamaged insulation, no interruptions
in cables and plugs, etc.
•Unexpected Voltages
Be prepared for the occurrence of unexpected volt-
ages at devices under test (e.g. defective devices, after
inspecting the winding resistance of contactor relays,
etc.). For example, capacitors can still be dangerously
charged.
Perform measurements on voltage-free objects only.
•Type-tested Fuses (cannot be replaced by the user)
Only use type-tested fuses, as specified in the Charac-
eristic Values. There is no protection against explo-
sions when other fuses are used.
In order to prevent major damage to the instrument
when interference voltage is applied (within the admis-
sible limit values), the mΩ/Ω measuring circuit is
equipped with a fuse F1 which makes these measur-

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ing circuits highly resistive for the duration of the over-
load when high currents occur as a result of a distur-
bance. Another fuse F2 is located in the path between
batteries and instrument.
•Dusty Atmosphere
The instrument may not be used in a dusty atmosphere.
Meanings of symbols on the instrument:
Warning concerning a source of danger
(attention: observe documentation!)
Ground
Continuous, doubled or reinforced
insulation
Indicates EC conformity
Symbol for explosion protection:
Electrical equipment for intended use in
potentially explosive environments per
EN 60079-11
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’.
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. This applies particularly
for potentially explosive environments.
Safe operation can no longer be relied upon,
• If the instrument or the test probes are damaged
• If the instrument no longer functions
• If the limits of the overload capacity have been
exceeded, e.g. after the fuse has blown
• After long periods of storage under unfavorable condi-
tions (e.g. humidity, dust, or excessive temperature),
see „Ambient Conditions“ on page 29.
!

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3InitialStart-Up
Insert Batteries
Warning!
Remove the instrument from the potentially explo-
sive environment before opening.
Only use the included type-tested batteries, as in-
dicated in the Characteristic Values.
Refer to chapter 10.1 regarding correct battery installation.
Note!
As a result of internal voltage monitoring, the instru-
ment may respond as follows if the battery voltage
level is low:
– Cannot be switched on
– Shuts back down immediately
– Shuts back down immediately when a load is
applied in the mΩrange.
If this is the case, replace the batteries.
Warning!
Never replace the batteries in potentially explosive
atmospheres.
Switching the Instrument On Manually
➭Press the ON|OFF key.
As long as the key is held depressed, all of the seg-
ments 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 mil-
liohmmeter is switched on. See also chapter 8.6.
Switching the Instrument On Automatically
The milliohmmeter is switched on automatically in the
transmission and memory modes.
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 batteries from the connector contacts.
Setting Time and Date
See chapter 8 on page 17.
Switching the Instrument Off Manually
➭Press the ON|OFF key until OFF is shown on the display.

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Shutdown is acknowledged with two, brief acoustic sig-
nals.
Switching the Milliohmmeter Off Automatically – „SLEEP MODE“
The instrument is switched off automatically if none of the
keys are activated for approximately 10 minutes. Shut-
down 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 auto-
matic shutdown.
Disabling Automatic Shutdown
The instrument can be set to continuous operation.
➭Press and hold the MENU/ESC 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
➭Briefly press the ON|OFF key after the instrument has al-
ready been switched on.
Illumination is switched off automatically after approxi-
mately 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 instru-
ment off and back on again in order to reset.
If the problem persists,
1 leave the potentially explosive environment,
2 disconnect the instrument from the measuring circuit before open-
ing and refer to chapter 10.1 „Batteries“,
3 Briefly dislodge the batteries from the connector contacts.

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4 Selecting Measuring Functions and Measuring
Ranges
4.1 Automatic Measuring Range Selection
The milliohmmeter is equipped with auto-ranging for all
measuring ranges. Auto-ranging is active as soon as the
instrument is switched on. The instrument automatically
selects the measuring range which allows for highest pos-
sible resolution for the applied quantity.
The instrument automatically switches to the next highest
or next lowest measuring range for the following measured
quantities:
4.2 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) or by switching the instru-
ment off and then back on again.
Note!
If the red ERROR LED lights up and OL is shown
on the display during manual measuring range
selection, you should switch to the next higher
range.
4.3 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 and to perform the following two functions:
•bymanual measuring range selection, i. e. by selecting
the measuring range with the best resolution, see
chapter 4.2.
or
Measuring Ranges Reso-
lution
Switching to next
highest range
at +(... d + 1 d)
Switching to next
lowest range
at +(... d –1 d)
300 mΩ, 3 Ω, 30 Ω4 ¾ 31 000 2 800
30 mΩ3 ¾ 3 100 280

MAN|
AUTO
Function
Acknow-
ledgement
Dis-
play
Acoust.
Signal
short Manual mode active:
utilized measuring range is fixed MAN 1 x
short Range switching sequence for:
mΩ:30mΩ→300 mΩ→3Ω→30 Ω→30 mΩ→… MAN 1 x
long Return to automatic range selection —2 x

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•viaDATA function, see chapter 6.1. After the first mea-
surement, the proper measuring range will be auto-
matically determined so that measurements are per-
formed more rapidly from the second measured value
onwards.
With both functions, the established measuring range is
maintained for the subsequent series mode measurments.
5 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.
“0L” (overload) appears if the measuring range upper limit is
exceeded for the following measured quantities (the red
ERROR LED lights up simultaneously and openl appears
on the auxiliary display):
300 mΩ, 3 Ω, 30 Ω: 30999
30 mΩ: 3099
The digital display is refreshed at different frequencies for
the various measured quantities.
The main display appears immediately after the milliohm-
meter is switched on, but the auxiliary displays have to be
activated by pressing the DATA | CLEAR key.
In the following flowcharts, the initial displays are high-
lighted through the use of a bold border line.
023.00
022.00 data
mΩ
Auxiliary Display Auxiliary Display
MAN
Main Display

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6 Measured Value Storage
The METRA HIT⏐27EX provides two entirely different
options for storing data:
•Measured Value Memory – DATA Key Function:
Each time the DATA key is pressed and a measuring
point is contacted, a measured value is stored (see
chapter 6.1).
•Memory Mode Operation – STORE Menu Function:
After activating the STORE menu function, all mea-
sured values are saved in accordance with the
selected sampling rate. Memory mode operation is
ended manually using the same menu function, see
chapter 8.2.
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 IR adapter
(BD232 or USB-HIT) has been plugged into the METRA
HIT⏐27EX and connected to the PC with an interface cable
(see Data Interface page 29).
6.1 Measured Value Storage – Key Function “DATA”
Measured values can be automatically “frozen” with the
DATA hold function. This is useful when, for example, con-
tacting the measuring points with the test probes requires
your full attention.
Preparation of Measurement
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 contigu-
ous fashion. Check current memory occupancy to this
end: INFO MEMO/OCCUP
Clear memory if required: MEMO CLEAr.
Performing Measurements
➭Press the DATA key.
The message data blinks and indicates readiness for
acquiring the first measured value.
➭Contact the measuring point as described in chapter
7.3.
After applying the test probes to the measuring point:
– the green LED OK indicates: safe measurement connection.
– The initially acquired value is transferred to the main
display where it remains stored. This is acknowledged
by two successive acoustic signals.
„MAN“ (and, additionally, „ZERO“ in the MΩmeasuring
ranges) is displayed simultaneously and indicates that
the measuring range is now fixed.
– the momentary measured values continue to be
shown in the auxiliary display on the left.
➭Lift the test probes from the measuring point.
The message openl appears on the auxiliary display.

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The red LED ERROR lights up as long as no contact has
been established between the test probes and the mea-
suring point. The green LED OK continues to light up when
a valid measured value has already been stored.
Prior to contacting the next measuring point, the function
DATA must be activated once more by pressing the DATA
key. The message data blinks and indicates readiness for
acquiring the next measured value.
As long as the DATA function is active and all measure-
ments are within the measuring range which has been
Acoustic signal 1x
0.L
openl
Ω
0.L
0.ldata
Ω
DATA
044.66
044.59 data
mΩ
MAN
Acoustic signal 2x
Meas. Contact
044.66
openl data
mΩ
MAN
Acoustic signal 2x
Disconnect contact
Acoustic signal 1x
DATA
044.66
openl data
mΩ
MAN
blinks
blinks
blinks
blinks
blinks
ERROR OK
OK
ERROR
OK
OK
ERROR
ERROR
ERROR
OK
ZERO
ZERO
ZERO

14 GMC-I Messtechnik GmbH
automatically adjusted, 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) or by switching the instru-
ment off and back on again.
7 Milliohm Measurement (4-Pole-Measurement)
7.1 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.
7.1.1 Measurement with Kelvin Probe KC27
mΩ
U+U– I+
red
black
black
Milliohm measurement on
conductor bars, welds,
coils, etc. with Kelvin probe
KC27 and Kelvin clip KC4
Direct the spring-loaded test
probe inward towards the DUT,
if possible, as it is connected
via the red plug with U+or U–
(Sense) .
I–

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7.2 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.
After switching on the milliohmmeter, „termoc“ is displayed,
indicating that an automatic thermovoltage compensation
for the 30 mΩ and 300 mΩ measuring ranges will be per-
formed in the background for all future measurements.
ZERO signals that the value of the thermovoltage has
already been taken into account for the indicated measu-
ring result.
After the first measurement – lift the test probe from the
measuring point – „termoc“ disappears to facilitate the rea-
ding of the measured values. The automatic thermovoltage
compansation remains activated.
000.10
termoC
m
mΩ
Ω
Measure
thermo-
voltage
Relevant measuring ranges:
30 mΩ und 300 mΩ
I < 100 mA
ZERO

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7.3 Milliohm Measurement with ≤100 mA DC [mΩ]
➭Make sure that the device under test is voltage-free.
➭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.
➭If applicable, select the desired measuring range using
the MAN|AUTO key: 30 mΩ,300 mΩ,3 Ωor 30 Ω.
➭Contact the measuring point.
The green LED OK must light up.
Note!
If the measuring current is interrupted during
4-wire-mΩ-measurement or if the fuse F1 is defec-
tive, the message „open L“ flashes on the display
and the red LED ERROR lights up.
If fuse is defective, see chapter 10.2.
mΩ
U+U–
Rx
Voltage Drop Measuring Current
mΩ: 0.01 mΩ…30 Ω
Overall Measuring Range:
+–
Measurement Cables,
KC27 or KC4
Note:
When using KC27 or
KC4 always set red
probe plug at U+or
U–, respectively.
I+
I–

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8 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.
➭The initial „1NF0 “menu is accessed by simultaneously
pressing and holding the MENU/ESC and ON|OFF keys
with the instrument switched on, until „1NF0 “appears
at the display.
➭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.
➭After accessing the desired main menu, the associated
submenus are opened by activating the key.
➭The desired parameter or the desired function is se-
lected by repeatedly pressing the  keys.
➭Acknowledge with the key in order to change the
corresponding parameter or parameters.
➭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.
➭The measuring mode is started by repeatedly pressing
the MENU/ESC key until the measuring display appears.
➭The milliohmmeter 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.
8.1 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. See page 24 for possible set-
tings. The lower limit of the sampling rate which cannot be
fallen short of, is 0.5 s.

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8.2 Saving Measured Values
The METRA HIT⏐27EX provides two entirely different
options for storing data:
•Messwertspeicherung – Tastenfunktion 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 6.1 and chapter 8.2.1).
•Memory Mode Operation – STORE Menu Function:
After activating the STORE menu function, all mea-
sured 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 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 HIT⏐27EX and
connected to the PC with an interface cable.
8.2.1 Memory Mode – DATA Key Function (see also chapter 6.1)
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 10 software. Date and time must be
reset if the batteries are depleted and/or 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 Δvalues, and no relative time
stamps.
Memory content can only be read out with the help of a
PC, an IR adapter (BD232), and METRAwin 10 analysis
software.
Stored measurement data blocks are retained even if the
instrument is without voltage supply.
Vorbereitungen für den Speicherbetrieb
Preparing for Memory Mode Operation
➭First set the sampling rate for memory mode operation,
and then start memory mode operation.
The sampling rate can also be changed during mem-
ory mode operation.
➭First select the desired measuring function and an ap-
propriate measuring range.
➭Check the battery voltage level before starting long-
term measurement recordings (see chapter 10.1 on
page 30).

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8.2.2 Memory Mode Operation – STORE Menu Function
➭First set the sampling rate for memory mode operation,
and then start memory mode operation.
The sampling rate can also be changed during mem-
ory mode operation.
➭First select the desired measuring function and an ap-
propriate measuring range.
➭Check the battery voltage level before starting long-
term measurement recordings, see chapter 10.1 on
page 30.
Starting Memory Mode Operation with Menu Functions
➭Open the “Operating Mode” menu (refer to the menu
diagram) and select the StorE function.
➭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.
➭Press the key in order to switch to the measuring
function.
The “SLEEP MODE” is still active, i.e. the device is
switched on and off automatically at sampling rates of long
duration (see chapter 3).
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 val-
ues also during the memory process.
The „STORE“ function cannot be started while the „DATA“
function is activated.
Exiting Memory Mode Operation with Menu Functions
➭Select the StorE menu.
➭Activate the key: StOP blinks.
➭Activate the key once again: the auxiliary displays
are cleared. Memory mode operation has now been
deactivated.
➭Press the key in order to return to the measuring
function.
➭Memory mode operation can also be exited by switch-
ing the instrument off.
8.3 Querying Memory Occupancy – INFO MEMO/OCCUP
Memory occupancy can be queried from the „1NF0 “menu.
The main display shows current occupancy as a percent-
age between 001 and 100%.

20 GMC-I Messtechnik GmbH
8.4 Clearing the Memory – MEMO CLEAr
Attention!
!
This function deletes all measured values from
memory.
This function cannot be performed during memory mode;
bUSY
MEMO
is displayed instead of CLEAR.
8.5 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.
➭Simultaneously press and hold the MENU/ESC, MAN|AUTO
and DATA| CLEAR keys, and switch the instrument on
with the ON|OFFkey.