Gossen MetraWatt METRAHIT ULTRA User manual

METRAHITULTRA and METRAHITULTRA BT
High Resolution TRMS Digital Multimeter
Operating Instructions
3-349-684-03
8/1.17

2GMC-I Messtechnik GmbH
Scope of Delivery Contact Persons
Scope of Delivery
1Multimeter
1 KS17-2 measurement cable set
2 Batteries
1 Condensed operating instructions
1
CD ROM (content: operating instructions, data sheet and more)
1 DAkkS calibration certificate
1 Rubber holster
Included Functions
1
16 Mbit = 2048 kByte = 300,000 measured values,
sampling rate adjustable from 0.1 seconds to 9 hours
Function METRAHIT ULTRA /
METRAHIT ULTRA BT
M248A / M248B
Voltage, VDC (Ri 10 M)
3
Voltage, VAC TRMS (Ri 5 M) 3
Voltage, VAC+DC TRMS (Ri 5 M) 3
Frequency, Hz @ VAC @ VAC+DC Up to 300 kHz
1 kHz low-pass filter @ VAC @ VAC+DC
Bandwidth @ VAC+DC or VAC 100 kHz
Pulse frequency, MHz @ 5 V TTL 1 Hz to 1 MHz
Duty cycle as % 2.0% to 98%
Voltage level measurement, dB @ VAC @ VAC+DC
Resistance,  3
Continuity test, ICONST = 1 mA 3
Diode test, I
CONST
= 1 mA 3
Temp. measurement C/F @ TCType K
Temp. measurement C/F RTD Pt100/Pt1000
Capacitance measurement, F 3
Current, ADC
300  A / 3 mA
30 mA / 300 mA
3A/10
A (16 A)
Current, AAC+DC TRMS
Current, AAC TRMS
Bandwidth @ AAC+DC or AAC 10 kHz
Frequency, Hz @ AAC @ VAC+DC Up to 30 kHz
Current clamp measurement with ad-
justable transformation ratio
mV / A
mA / A
Data logger function 1(memory) 16 MBit (2 MB)
Relative value measurement REL
3
Zero point 3
Min / Max / Data Hold 3
IR interface (38.4 kBd) 3
Bluetooth interface (38.4 kBd) M248B only
Power pack socket
3
Rubber holster 3
Fuse 10 A / 1000 V
Protection IP 52
Measuring category 600 V CAT III
300 V CAT IV
DAkkS Calibration Certificate
3
Function METRAHIT ULTRA /
METRAHIT ULTRA BT
M248A / M248B

GMC-I Messtechnik GmbH 3
Contact Persons
Accessories (sensors, plug inserts, adapters, consumable materials)
The accessories available for your instrument are checked for
compliance with currently valid safety regulations at regular inter-
vals, and are amended as required for new applications. Currently
up-to-date accessories which are suitable for your measuring in-
strument 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
See also section 10 on page 70.
Product Support
Technical Queries
(use, operation, software registration)
If required please contact:
GMC-I Messtechnik GmbH
Product Support Hotline
Phone: [phone]
Fax: [phone]
e-mail: [email protected]
Software Enabling for METRAwin10 (as of version 6.xx)
GMC-I Messtechnik GmbH
Front Office
Phone: [phone]
Fax: [phone]
e-mail: [e-mail]

4GMC-I Messtechnik GmbH
Scope of Delivery Contact Persons
Recalibration Service
Our service center calibrates and recalibrates all instruments sup-
plied by GMC-I Messtechnik GmbH, as well as other manufactur-
ers, (for example after one year as part of your test equipment
monitoring system, and prior to use etc.) and offers free test
equipment management.
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 Nürnberg, Germany
Phone: [phone]
Fax: [phone]
e-mail: [e-mail]
www.gmci-service.com
This address is only valid in Germany. Please contact our repre-
sentatives or subsidiaries for service in other countries.
* DAkkS calibration laboratory for measured electrical quantities,
D-K-15080-01-01, accredited in accordance with DIN EN ISO/IEC 17025
Accredited quantities: direct voltage, direct current value, direct current
resistance, alternating voltage, alternating current value, AC active
power, AC apparent power, DC power, capacitance, frequency, tem-
perature
Competent Partner
GMC-I Messtechnik GmbH is certified in accordance with
DIN EN ISO 9001.
Our DAkkS calibration laboratory is accredited by the Deutsche
Akkreditierungsstelle GmbH (national accreditation body for the
Federal Republic of Germany) under registration number D-K-
15080-01-01 in accordance with DIN EN ISO/IEC 17025.
We offer a complete range of expertise in the field of metrology:
from test reports and factory calibration certificates right on up to
DAkkS calibration certificates.
Our spectrum of offerings is rounded out with free test equipment
management.
As a full service calibration laboratory, we can calibrate instru-
ments from other manufacturers as well.

GMC-I Messtechnik GmbH 5
Contact Persons

6GMC-I Messtechnik GmbH
Table of Contents
Content Page Content Page
1 Safety Features and Precautions ....................................... 8
1.1 Use for Intended Purpose ................................................................10
1.2 Meanings of Danger Symbols ..........................................................11
1.3 Meanings of Acoustic Warning Signals ............................................11
2 Operating Overview – Connections, Keys, Rotary Switch, Symbols . 12
3 Initial Start-Up .................................................................. 16
3.1 Inserting Batteries or Rechargeable Batteries ...................................16
3.2 Switching the Instrument On ...........................................................16
3.3 Setting the Operating Parameters ....................................................16
3.4 Switching the Instrument Off ...........................................................17
4 Control Functions ............................................................. 18
4.1 Selecting Measuring Functions and Measuring Ranges .....................18
4.1.1 Automatic Range Selection .............................................................18
4.1.2 Manual Measuring Range Selection .................................................19
4.1.3 Quick Measurements ......................................................................20
4.2 Zero Offset / Relative Measurements ...............................................20
4.3 Display (LCD) .................................................................................21
4.4 Measured Value Storage: DATA (auto-hold / compare) ......................22
4.4.1 Saving Minimum and Maximum Values – Min/Max Function .............23
4.5 Measurement Data Recording .........................................................24
4.5.1 Long-Term Recording .....................................................................24
4.5.2 Storage of Individual Values using the SAMPLE or dAtA Sampling Rate ......... 26
5 Measurements ................................................................. 28
5.1 Voltage Measurement ....................................................................28
5.1.1 Direct and Pulsating Voltage Measurement, V DC and V (DC+AC) .....29
5.1.2 Alternating Voltage and Frequency Measurement V AC and Hz
V AC with Selectable Low-Pass Filter, V AC + FiL and dB V AC .........31
5.1.3 Transient Overvoltages ...................................................................34
5.1.4 Voltage Measurements at Above 600 V ...........................................34
5.1.5 Frequency and Duty Cycle Measurement .........................................35
5.2 Resistance Measurement 
5.3 Continuity Test with Constant Current of 1 mA ................................37
5.4 Diode Testing with Constant Current of 1 mA ..................................38
5.5 Temperature Measurement ............................................................39
5.5.1 Measurement with Thermocouples, Temp TC ..................................39
5.5.2 Measurement with Resistance Sensors ...........................................40
5.6 Capacitance Measurement ............................................................41
5.7 Current Measurement ....................................................................42
5.7.1 Direct and Pulsating Current Measurement, Direct Connection, A DC and
A (DC+AC) .....................................................................................43
5.7.2 Alternating Current and Frequency Measurement,
Direct Connection, A AC and Hz ......................................................44
5.7.3 Direct and Pulsating Current Measurement with Current Clamp Sensor, A
DC and A (DC+AC) .........................................................................45
5.7.4 Alternating Current Measurement with Current Clamp Sensor,
A AC and Hz ..................................................................................46
5.7.5 Alternating Current Measurement with Current Clamp Transformer, A AC
and Hz ...........................................................................................47

GMC-I Messtechnik GmbH 7
Table of Contents
Content Page Content Page
6 Device and Measuring Parameters ................................... 48
6.1 Paths to the Various Parameters .................................................... 49
6.2 List of All Parameters .................................................................... 49
6.3 Querying Parameters – InFo Menu .................................................. 50
6.4 Entering Parameters – SETUP Menu ............................................... 51
6.5 StorE Menu – Parameter for Memory Mode Operation ..................... 53
6.6 Default Settings ............................................................................. 55
7 Interface Operation ...........................................................56
7.1 Activating the Interface ................................................................... 56
7.2 Configuring Interface Parameters .................................................... 57
8 Technical Data ..................................................................58
9 Maintenance and Calibration ............................................ 66
9.1 Displays – Error Messages ............................................................ 66
9.2 Batteries ....................................................................................... 66
9.3 Fuse ............................................................................................. 67
9.4 Housing Maintenance .................................................................... 68
9.5 Return and Environmentally Sound Disposal .................................... 68
9.6 Recalibration ................................................................................. 69
9.7 Manufacturer’s Guarantee .............................................................. 69
10 Accessories .......................................................................70
10.1 General ......................................................................................... 70
10.2 Technical Data for Measurement Cables
(scope of delivery: KS17-2 safety cable set) .................................... 70
10.3 NA X-TRA Power Pack (not included) .............................................. 70
10.4 Interface Accessories (not included) ................................................ 71
10.4.1 Infrared Interface ........................................................................... 71
10.4.2 Bluetooth Interface ........................................................................ 71
11 Index .................................................................................72

8GMC-I Messtechnik GmbH
Safety Precautions
1 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
mark. The relevant declaration of conformity can be obtained from
GMC-I Messtechnik GmbH.
The TRMS digital multimeter has been manufactured and tested
in accordance with the following safety regulations:
IEC 61010–1:2010/DIN EN 61 010–1:2010/VDE 0411–1:2011.
When used for its intended purpose (see page 10), 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 thor-
oughly and carefully before placing your instrument into service, and that
you follow all instructions contained therein.
The multimeter is equipped with an automatic socket blocking
mechanism for your safety, and in order to safeguard your instru-
ment. This mechanism is linked to the rotary switch and only al-
lows access to those jacks which are actually required for the se-
lected function. It also prevents the user from turning the rotary
switch to impermissible functions after the measurement cables
have already been plugged in.
If dangerous voltages are applied in the high-impedance voltage
measuring functions (switch position V), switching to low-imped-
ance measuring functions (switch position , continuity, tempera-
ture or capacitance) causes “HiVoLt” to appear at the display and
the respective measurement is disabled.
Hazardous touch voltages are not detected when the ohm or
capacitance measurement is selected.
If the instrument switches itself off in the event that hazardous
touch voltage is applied (only possible during memory mode
operation), the high-voltage warning symbol remains visible at the
display.
Measuring Categories and their Significance per IEC 61010-1
The measuring category and the maximum rated voltage which
are printed on the device apply to your measuring instrument, for
example 600 V CAT III.
Refer to section 10 regarding use of the measurement cables.
Observe the following safety precautions:
• The multimeter may not be used in potentially explosive atmo-
spheres or in the vicinity of unprotected detonators or other ex-
plosive material.
•TheBluetooth function may not be activated on board of air-
crafts according to the FCC or FAA guidelines as critical aircraft
instruments might be disturbed.
CAT Definition
IMeasurements in electrical circuits which are not directly connected to the mains:
e.g. electrical systems in motor vehicles and aircraft, batteries etc.
II
Measurements in electrical circuits which are electrically connected to the low-
voltage mains:
via plug, e.g. in household, office and laboratory applications
III
Measurements in building installations:
Stationary consumers, distributor terminals, devices connected permanently to the
distributor
IV Measurements at power sources for low-voltage installations:
meters, mains terminals, primary overvoltage protection devices

GMC-I Messtechnik GmbH 9
Safety Precautions
• The multimeter may only be operated by persons who are ca-
pable of recognizing touch hazards and taking the appropriate
safety precautions. Touch hazards according to the standard
exist anywhere, where voltages of greater than 33 V TRMS or
70 V DC may occur. Avoid working alone when taking mea-
surements which involve touch hazards. Be certain that a sec-
ond person is present.
•Maximum allowable voltage between the voltage measuring
sockets or all connector sockets and ground is 600 V for mea-
suring category III and 300 V for measuring category IV.
• Be aware of the fact that dangerous voltage peaks with signifi-
cant frequency components of greater than 1 kHz are not dis-
played when the low-pass filter is activated. We recommend
measuring voltage without the low-pass filter first, in order to
be able to detect any dangerous voltages.
• Be prepared for the occurrence of unexpected voltages at de-
vices under test (e.g. defective devices). For example, capaci-
tors may be dangerously charged.
• Make certain that the measurement cables are in flawless con-
dition, e.g. no damage to insulation, no interruptions in cables
or plugs etc.
• No measurements may be made with this instrument in electri-
cal circuits with corona discharge (high-voltage).
• Special care is required when measurements are made in HF
electrical circuits. Dangerous pulsating voltages may be pres-
ent.
• Measurements under moist ambient conditions are not permit-
ted.
• Be absolutely certain that the measuring ranges are not over-
loaded beyond their allowable capacities. Limit values are in-
cluded in section 8, “Technical Data”, in the table entitled
“Measuring Functions and Measuring Ranges” in the “Over-
load Capacity” column.
•The multimeter may only be operated with installed batteries or
rechargeable batteries. Dangerous currents and voltages are
otherwise not indicated, and the instrument may be damaged.
• Observe visual and acoustic warning signals!
• The instrument may not be operated if the fuse cover or the
battery compartment lid has been removed, or if its housing is
open.
• The input for the current measuring range is equipped with a
fuse link.
Use specified fuses only (see page 63)! The fuse must have a
breaking capacity of at least 30 kA.

10 GMC-I Messtechnik GmbH
Safety Precautions
Opening of Equipment / Repair
The equipment may be opened only by authorized service per-
sonnel to ensure the safe and correct operation of the equipment
and to keep the warranty valid.
Even original spare parts may be installed only by authorized ser-
vice personnel.
In case the equipment was opened by unauthorized personnel,
no warranty regarding personal safety, measurement accuracy,
conformity with applicable safety measures or any consequential
damage is granted by the manufacturer.
Repair and Parts Replacement by authorized service personnel
When the instrument is opened, voltage conducting parts may be
exposed. The instrument must be disconnected from the measur-
ing circuit before performing repairs or replacing parts. If repair of
a live open instrument is required, it 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 oper-
ated safely, it must be removed from service and secured against
unintentional use.
Safe operation can no longer be relied upon:
• If the device demonstrates visible damage
• If the instrument no longer functions, or if malfunctioning
occurs
• After long periods of storage under unfavorable conditions (e.g.
humidity, dust or extreme temperature (see “Ambient Condi-
tions” on page 64)
1.1 Use for Intended Purpose
• The multimeter is a portable device which can be held in the
hand during the performance of measurements.
• Only those types of measurements described in section 5 may
be performed with the measuring instrument.
• The measuring instrument, including measurement cables and
plug-on test probes, may only be utilized up to the maximum
specified measuring category (see page 63 and the table on
page 8 regarding significance).
If the measuring categories specified for the measuring instru-
ment and the measurement cables differ from each other, the
lower category applies to the application.
• Overload limits may not be exceeded. See technical data on
page 58 for overload values and overload limits.
• Measurements may only be performed under the specified
ambient conditions. See page 64 regarding operating tem-
perature range and relative humidity.
• The measuring instrument may only be used in accordance
with the specified degree of protection (IP code) (see page 64).

GMC-I Messtechnik GmbH 11
Safety Precautions
1.2 Meanings of Danger Symbols
Warning concerning a point of danger
(attention, observe documentation!)
Symbol on the LCD:
Warning concerning dangerous voltage at the measurement
input: U > 45 V
Note
The auto power off function (APoFF parameter) is deactivated
when dangerous touch voltage is applied.
1.3 Meanings of Acoustic Warning Signals
Voltage warning: > 600 V (intermittent acoustic signal)
Current warning: > 10 A (intermittent acoustic signal)
Current warning: > 16 A (continuous acoustic signal)
!

12 GMC-I Messtechnik GmbH
Operating Overview – Connections, Keys, Rotary Switch, Symbols
2 Operating Overview – Connections, Keys, Rotary Switch, Symbols
1 Display (LCD) (see page 14 for significance of symbols)
2MAN / AUTO shift key for manual/automatic range selection
Increase parameter values
Operating mode menu:
select menu entries against flow direction
3 ON / OFF | LIGHT , on/off key for switching device and display light
4FUNC | ENTER multifunction key
Operating mode menu: acknowledge entry (ENTER)
5
Increase measuring range or move decimal point to right (MAN function)
6Rotary switch for measuring functions, (see page 15 for significance of sym-
bols)
7 DAkkS calibration seal
8 Connector socket for ground / connected to ground
9 Connector socket for current measurement with auto-blocking
10 Connector socket for voltage, resistance, temperature, diode and capaci-
tance measurement with automatic blocking
11 DATA/MIN/MAX
Key for freezing, comparing and deleting the measured value, and for the
Min-Max function
Decrease values
Operating mode menu: select of menu entries in flow direction
12 MEASURE | SETUP
Key for switching between measuring and menu functions
13 ZERO | ESC
Key for zero balancing
Operating mode menu: Exit current menu level and return to a
higher level, exit parameters
configuration without saving data
14 
Decrease measuring range or move decimal to left (MAN function)
15 Power pack connector jack
16 Infrared interface
1
3
4
16
5
6
9
*
section 4.3
section 3
section 5
section 7
section 6
section 3 ff.
section 3
13
12
section 4.1
10
2section 4.1
14
8
Max. 600 V!
11
15
section 4.1 
section 4.4 
section 6 
section 3 
section 6 
section 3.1 
7
section 1.2

GMC-I Messtechnik GmbH 13
Operating Overview – Connections, Keys, Rotary Switch, Symbols
Symbols Used in the Digital Display 1 Battery level indicator
2 ON: continuous operation (automatic shutdown deactivated)
3 DATA: display memory, “freeze measured value”
4 STORE: memory mode active
5 FILTER: low-pass filter active
6IR: infrared interface indicator
7 Bluetooth interface control display
8Auxiliary display: digital display with decimal point and polarity display
9 Transformation ratio (factor for current sensor and transformer clamps)
10 dB: alternating voltage level measurement
11 Selected type of current
12 TRMS measurement
13 Unit of Measure
14 Warning regarding dangerous voltage: U > 45 V AC/DC
15 Main display : digital display with decimal point and polarity display
16 Continuity test with acoustic signal active
17 Pt100/Pt1000: selected platinum resistance sensor with automatic recog-
nition of Pt100/Pt1000
18 TC: temperature measurement with type K thermocouple (NiCr-Ni)
19 h (hours): unit of time
20 MAN: manual measuring range selection active
21 ZERO: zero balancing active
22 REL: relative measurement with reference to offset
23 min: minimum value storage
24 Diode measurement selected
25 max: maximum value storage
26 Stopwatch active or time since beginning of measurement
27 ON: no function here
28 sec (seconds): unit of time
29 Upm : no function here
Battery full
Battery OK
Battery weak
Battery (almost) dead, U < 1.8 V
Data transmissionto / from multimeter active
IR interface in standby mode
(ready to receive starting commands)
Battery Level Indicator
Interface Indicator
126
8
13
14
16
4 5
7
3
10
12
9
18
23 262019
17
15
24
11
21 22 25 2728 29
7

14 GMC-I Messtechnik GmbH
Operating Overview – Connections, Keys, Rotary Switch, Symbols
Symbols Used for Rotary Switch Positions
Switch FUNC Main Display Auxiliary Display Measuring Function
V~ 0/4 V~ AC TRMS Hz Alternating voltage, AC TRMS, full bandwidth / voltage frequency
Hz (V) 1 Hz V~ AC Voltage frequency, up to 300 kHz / alternating voltage, AC TRMS
V~ 2 V FILTER ~ AC TRMS Hz Alternating voltage, AC TRMS, with low pass filter (1 kHz) / voltage frequency
dB 3 dB V~ AC TRMS Alternating voltage level measurement
V0/4 V DC+AC TRMS Hz Pulsating voltage, TRMS ( ) / voltage frequency
V1 Hz V DC+AC TRMS Voltage frequency / pulsating voltage, TRMS
V2 V FILTER DC+AC TRMS Hz Pulsating voltage, TRMS with low pass filter (1 kHz) / voltage frequency
dB 3 dB V DC+AC TRMS Alternating voltage level measurement
V 0/2 V DC — Direct voltage
MHz 0/2 MHz —(High) frequency at 5 V~ up to 1 MHz
%1 % Hz Duty cycle / frequency
——(DC)resistance
0/2 — Continuity test () with acoustic signal
1V DC — Diode voltage up to max. 4.5 V
Temp. TC 0/2 C, type K C internal temp. at jacks Temperature, type K thermocouple
Temp. RT D 1°Pt100 Temperature with Pt100 / Pt1000 resistance sensor
— nF — Capacitance
A0/3 A DC — Direct current value
A1 A DC+AC TRMS Hz Pulsating current amperage, TRMS AC+DC / current frequency
A2 Hz A DC +AC TRMS Frequency / pulsating current amperage, TRMS AC DC
A~ 0/2 A~ AC TRMS Hz Alternating current amperage, TRMS AC / current frequency
Hz (A) 1 Hz ~ AC Hz ~ AC Current frequency / alternating current amperage, TRMS AC
0/3 A DC — DC amperage with AC DC Current clamp sensor, 1 V:1/10/100/1000 A
1
A DC+AC TRMS Hz Pulsating current amperage, TRMS / current frequency with AC DC current clamp sensor, see above
2
Hz A DC+AC TRMS Current frequency / pulsating current amperage, TRMS, with AC DC current clamp sensor, see above
0/2 A~ AC TRMS Hz Alternating current amperage, TRMS, with Current clamp sensor, see above
Hz ( ) 1 Hz ~ AC ~ AC Current frequency
1kHz
VAC DC+VAC
2VDC 2
+=
A
A
A
A
A

GMC-I Messtechnik GmbH 15
Operating Overview – Connections, Keys, Rotary Switch, Symbols
User Interface Symbols in the Following Sections
... Scroll through main menu
... Scroll through submenu
Select decimal point
 Increase/decrease value
time Submenu/parameter (7-segment font)
1nFo Main menu (7-segment font, boldface)
Symbols on the Device
Warning concerning a point of danger
(attention, observe documentation!)
Ground
CAT III / IV Measuring category III or IV device, see also
“Measuring Categories and their Significance per IEC
61010-1” on page 8
Continuous, doubled or reinforced insulation
EC mark of conformity
sIR tPosition of the infrared interface, window on the top of
the instrument
Position of the power pack adapter socket,
see also section 3.1
Fuse for current measuring ranges, see section 9.3
This device may not be disposed of with the trash.
Further information regarding the WEEE mark can be
accessed on the Internet at www.gossenme-
trawatt.com under the search term WEEE (see also
section 9.5).
Calibration Seal (blue seal):
See also “Recalibration” on page 69.
!
5V/600mA
XY123
2012-06
D-K
15080-01-01
Consecutive number
Registration number
Date of calibration (year – month)
Deutsche Akkreditierungsstelle GmbH – calibration lab

16 GMC-I Messtechnik GmbH
Initial Start-Up – Setup
3 Initial Start-Up
3.1 Inserting Batteries or Rechargeable Batteries
Be certain to refer to section 9.2 regarding correct battery installa-
tion.
Momentary battery voltage can be queried in the Info menu (see
section 6.3).
Attention!
!
Disconnect the instrument from the measuring circuit before
opening the battery compartment lid in order to replace the
batteries.
Operation with the Power Pack
(accessory for METRAHIT ULTRA, not included, see section 10.3)
Installed batteries are disconnected electronically if the NA X-TRA
power pack is used, and need not be removed from the instru-
ment.
If rechargeable batteries are used, they must be recharged exter-
nally.
If the external power supply is switched off, the device is switched
to battery operation without interruption.
3.2 Switching the Instrument On
Switching the Instrument On Manually
ÐPress the ON / OFF | LIGHT key until the display appears.
Power-up is acknowledged with a brief acoustic signal. As
long as the key is held depressed, all of the segments at the
liquid crystal display (LCD) are illuminated.
The LCD is depicted on page 13.
The instrument is ready for use as soon as the key is released.
Display Illumination
After the instrument has been switched on, background illumina-
tion can be activated by briefly pressing the ON / OFF | LIGHT key. Il-
lumination is switched back off by once again pressing the same
key, or automatically after approximately 1 minute.
Switching the Instrument On with a PC
The multimeter is switched on after transmission of a data block
from the PC, assuming that the “irStb” parameter has been set to
“iron” (see section 6.4).
However, we recommend using the power saving mode: “ir off”.
Note
Electrical discharge and high frequency interference may
cause incorrect displays to appear, and may disable the
measuring sequence.
Disconnect the device from the measuring circuit. Switch the
instrument off and back on again in order to reset. If the
problem persists, briefly dislodge the battery from the con-
nector contacts (see also section 9.2).
3.3 Setting the Operating Parameters
Setting Time and Date
See the “tiME” and “dAtE” parameter in section 6.4.

GMC-I Messtechnik GmbH 17
Initial Start-Up – Setup
3.4 Switching the Instrument Off
Switching the Instrument Off Manually
ÐPress the ON / OFF | LIGHT key until 0FF appears at the display.
Shutdown is acknowledged with a brief acoustic signal.
If hazardous contact voltage has been detected (HV symbol
appears), the instrument cannot be switched off.
Automatic Shutdown
The instrument is switched off automatically if the measured value
remains unchanged for a long period of time (maximum measured
value fluctuation of approx. 0.8% of the measuring range per min-
ute or 1C or 1per minute), and if none of the keys or the rotary
switch have been activated before a selected period of time in
minutes has elapsed (see “APoFF” parameter on page 51). Shut-
down is acknowledged with a brief acoustic signal.
Automatic shutdown is disabled in the following operating modes:
continuous operation and whenever dangerous contact voltage
has been detected (exception: memory mode).
Disabling Automatic Shutdown
The instrument can be set to continuous operation.
ÐWhile switching the instrument on, simultaneously press the
and keys to this end.
The “Continuous On” function is indicated at by means of the
ON display to the right of the battery symbol.
The “Continuous On” setting can only be canceled by changing the
respective parameter (see “APoFF” page 51) or by switching the
instrument off manually.
In this case, the parameter is reset to 10 minutes.
ON / OFF
LIGHT
FUNC
ENTER
ON / OFF
LIGHT
Auto-Range
8.8.8.8.8
Illumination ON
000.00
ON / OFF
LIGHT
Illumination OFF
000.00
ON / OFF
LIGHT
0ff
ON / OFF
LIGHT
long
(1 s)

18 GMC-I Messtechnik GmbH
Control Functions
4 Control Functions
4.1 Selecting Measuring Functions and Measuring Ranges
The rotary switch is linked to the automatic socket blocking
mechanism, which only allows access to two connector jacks for
each function. Be certain to remove the appropriate plug from its
respective jack before switching to and from the “A” functions.
The socket blocking mechanism prevents the user from inadver-
tently turning the selector switch to impermissible functions after
the measurement cables have been plugged into the instrument.
Presence of Dangerous Touch Voltages
If dangerous volt-
ages are applied in
the high-imped-
ance voltage mea-
suring functions
(switch position V
or PQ), switching
to low-impedance
measuring func-
tions (switch posi-
tion MHz, , conti-
nuity, temperature
or capacitance)
causes “HiVoLt” to
appear at the dis-
play and the re-
spective measure-
ment is disabled. The measuring function is not switched until
dangerous touch voltage is no longer applied to the input. If the
instrument switches itself off in the event that hazardous touch
voltage is applied (during memory mode operation with large
sampling period), the high-voltage warning symbol remains visible
at the display.
4.1.1 Automatic Range Selection
The multimeter is equipped with auto-ranging for all measuring
functions, except for temperature measurement and diode and
continuity testing. Auto-ranging is active as soon as the instru-
ment is switched on. The instrument automatically selects the
measuring range which allows for highest possible resolution of
the applied quantity.
AUTO-Range Function
The instrument is switched automatically to the next higher range
at (310,000 d + 1 d) 031,000 digits, and to the next lower
range at (28,000 d – 1 d) 27,999 digits.
The instrument automatically switches to the next higher or next
lower measuring range for the following measured quantities:
230 . 00
V
050 . 00
AC
TRMS
Hz
U > 45 V:
V~
V
VTem p
TC
Temp
RTD
hivolt
Measuring Range Reso-
lution
Switching to Next
Higher Range
at (... d + 1 d)
Switching to Next
Lower Range
at (... d -1 d)
V,A,, Hz 5¾ 310,000 28,000
V , V , A , A 4¾ 31,000 2800
3 nF ... 3 mF 3¾ 3100 280

GMC-I Messtechnik GmbH 19
Control Functions
4.1.2 Manual Measuring Range Selection
Auto-ranging can be deactivated and measuring ranges can be
selected manually in accordance with the following table by
pressing the MAN / AUTO button.
The desired measuring range can then be selected with the or
scroll key.
The instrument is automatically returned to automatic range se-
lection when the MAN / AUTO key is pressed, the rotary switch is
activated or the instrument is switched off and back on again.
Overview: Auto-Ranging and Manual Range Selection
* Via manual measuring range selection only
Function Display
MAN / AUTO
Manual mode active:
utilized measuring range is fixed MAN
or 
Range switching sequence for:
V : 300 mV*  3V  30 V  300 V  600 V
Hz (V AC) :300 Hz  3 kHz  30 kHz  300 kHz
MHz: 300 Hz  3 kHz  30 kHz  300 kHz  1 MHz
 : 300  3 k  30 k  300 k  3 M  30 M 
A : 300  A  3 mA  30 mA  300 mA  3A  10 A (16 A)
Hz (A AC): 300 Hz  3 kHz  30 kHz
F : 3 nF  30 nF  300 nF  3  F  30  F  300  F 
 3  mF
MAN
MAN / AUTO Return to automatic measuring range selection —

20 GMC-I Messtechnik GmbH
Control Functions
4.1.3 Quick Measurements
Measurements performed using a suitable fixed measuring range
are executed more quickly than those which utilize automatic
range selection. Quick measurement is made possible with the
following two functions:
•Manual measuring range selection, i.e. selection of the measuring
range with the best resolution (see section 4.1.2)
or
•WiththeDATA function (see section 4.4). In this way, the appro-
priate measuring range is selected automatically after the first
measurement, and the second measurement is executed more
quickly.
The selected measuring range remains active for the subsequent
series of measurements with these two functions.
4.2 Zero Offset / Relative Measurements
Zero offset or a reference value for relative measurements can be
stored to memory depending upon deviation from the zero point:
The relevant reference or correction value is deducted individually
for the respective measuring function as an offset from all future
measurements and remains in memory until deleted, or until the
multimeter is switched off.
Zero balancing and reference value adjustment can be used for
auto-ranging, as well as for manual measuring range selection.
Zero Balancing
ÐPlug the measuring cables into the instrument and connect the
free ends to each other, except for capacitance measurement
in which case the ends of the cables are not connected to
each other.
ÐBriefly press the ZERO | ESC key.
The instrument acknowledges zero balancing with an acoustic
signal, and the “ZERO REL” symbol appears at the LCD. The
value measured at the moment the key is pressed serves as a
reference value.
ÐZero balancing can be cleared by once again pressing the
ZERO | ESC key.
Note
As a result of TRMS measurement, the multimeter can dis-
play a residual value of 1 to 30 digits with short-circuited
measurement cables as the zero point for V AC / I AC or
V(AC+DC) / I (AC+DC) measurements (non-linearity of the
TRMS converter). This has no influence on specified accu-
racy of the measuring range.
Setting the Reference Value
ÐPlug the measuring cables into the instrument and measure a
reference value (max. 150,000 digits, in the 10 A DC range:
50,000 digits = 50% of the measuring range).
Deviation from zero
– With short-circuited measurement cables for V, , A
– With open input for capacitance unit of measure (F)
Display
0 to 200 digits ZERO REL
> 200 D to (150,000 digits) 50% of the measuring range REL