Conrad VC 350E User manual

OPERATING INSTRUCTIONS
Digital Multimeter
VC 350E
Item-No.: 12 55 12
NOTICE D´EMPLOI
Multimètre numérique
VC 350E
No de commande: 12 55 12
BEDIENUNGSANLEITUNG
Digitalmultimeter
VC 350E
Best.-Nr.: 12 55 12
GEBRUIKSAANWIJZING
Digitale Multimeter
VC 350E
Best.-Nr.: 12 55 12
NL
D
F
GB
Pagina 136 - 178
Seite 92 - 135
Page 44 - 91
Page 2 - 43
CONRAD IM INTERNET http://www.conrad.de
Imprint
These operating instructions are published by Conrad Electronic GmbH, Klaus-Con-
rad-Str. 1, 92240 Hirschau/Germany
No reproduction (including translation) is permitted in whole or part e.g. photoco-
py, microfilming or storage in electronic data processing equipment, without the
express written consent of the publisher.
Theoperatinginstructions reflect the current technical specifications at timeof print.
We reserve the right to change the technical or physical specifications.
©
Copyright 1998 by Conrad Electronic GmbH. Printed in Germany.
Note de l´éditeur
Cette notice est une publication de la société Conrad Electronic GmbH, Klaus-Con-
rad-Str. 1, 92240 Hirschau/Allemagne.
Tous droits réservés,y compris traduction.Toute reproduction, quel que soit le type,
par exemple photocopies, microfilms ou saisie dans des traitements de texte elec-
tronique est soumise à une autorisation préalable écrite de l`éditeur.
Impression, même partielle, interdite.
Cette notice est conforme à la règlementation en vigueur lors de l´impression.
Données techniques et conditionnement soumis à modifications sans aucun préalable.
©
Copyright 1998 par Conrad Electronic GmbH. Imprimé en Allemagne.
Impressum
Diese Bedienungsanleitung ist eine Publikation der Conrad Electronic GmbH.
Alle Rechte einschließlich Übersetzung vorbehalten. Reproduktionen jederArt, z. B.
Fotokopie, Mikroverfilmung, oder die Erfassung in elektronischen Datenverarbei-
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Nachdruck, auch auszugsweise, verboten.
Diese Bedienungsanleitung entspricht dem technischen Stand bei Drucklegung.
Änderung inTechnik undAusstattung vorbehalten.
©
Copyright 1998 by Conrad Electronic GmbH. Printed in Germany.
Impressum
Deze gebruiksaanwijzing is een publikatie van Conrad Electronic Ned BV.
Alle rechten, inclusief de vertaling,voorbehouden.Reprodukties van welke aard dan
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©
Copyright 1998 by Conrad Electronic Ned BV. Printed in Germany.
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3
• Continuity checking and diode test
• Measurement of frequency up to 2 MHz max.
• Measurement of temperature from -40°C to +1000°C max.,
-40°F to +1999°F max.
• Measurement in damp areas, outside, or in unfavourable envi-
ronmental conditions, is not permitted. Unfavourable environ-
mental conditions include:
- wetness or excessive air humidity,
- dust and combustible gases, vapours or solvents,
- strong vibrations,
- strong magnetic fields, as in the vicinity of machines or louds-
peakers,
- static electricity (fields and discharges).
Any use other than the one described above can lead to damage
to the product, and can also cause hazards, such as, for example,
short-circuit, fire, electric shock, etc.. No part of the product must
be modified or converted!! Safetyinformation must be observed!
2. Introduction, presentation
This multimeter is equipped with several special features, which
usefully expand certain measurements: a second, smaller 41/2-posi-
tion display for the simultaneous display of a set value and the
present measurement value, a measurement value store with
memory for up to 8 measurement values, a comparison function
for comparing measurement values, etc.
The instrument has an AUTO RANGE feature, such that with dif-
ferent measurements the appropriate measuring range is always
set. The REL function allows reference value measure-ments, in
which the difference value is displayed in the small display and the
2
Digital Multimeter VC 350E
Attention! You must read this!!
Please read this user manual thoroughly. In the event of damages
which arise due to non-observance of the User Manual, any gua-
rantee claim will be void. Non-observance of the manual may also
result in danger to the user!! We accept no liability for conse-
quential damage which results from this. Keep this User Manual
in a safe place .
List of contents Page
1. Intended use..............................................................................2
2. Introduction, presentation........................................................3
3. Safety information....................................................................4
4. Description of the operating elements....................................8
5. Using the multimeter..............................................................10
6. Performing measurements .....................................................27
7. Maintenance and calibration..................................................40
8. Technical data and measuring tolerances..............................41
1.Intended use of the measuring device
• Measurement of direct voltages up to a maximum of 1000 VDC
• Measurement of AC voltages up to 750 VAC max.
• Measurement of direct and alternating currents (True rms) up to
max. 20 A (protected)
• Measurement of resistances up to max. 40 MΩ, in 7 stages.
• Measurement of capacity up to 400 uF max.
GB

5
• Current measurements may only be carried out in circuits which
are themselves fused at 16 A or in which no voltage greater
than 250 VDC/VAC rms or powers greater than 4000 VA can
arise. The measuring device must not be used in installations of
overvoltage category III in accordance with IEC 664. The measu-
ring device and instrument leads are not protected against arc
explosions (IEC 1010-2-031, Section 13.101). The unit may be
used ungrounded with up to 750 VAC or 1000 VDC between
V/Ohm and COM only in Overvoltage category II installations
per IEC 664.
• Measuring devices and their accessories are not toys and do not
on any account belong in children's hands!
• In industrial facilities the accident prevention regulations of the
Industrial Employers' Liability Association for electrical systems
and equipment must be observed.
• In schools, training facilities, hobby and self-help workshops,
the handling of measuring devices must be supervised responsi-
bly by trained personnel.
• When opening covers or removing components, except where
this can be performed manually, live parts may be exposed.
Connection points may also be live. Before any adjustment,
maintenance, repair or replacement of components or assem-
blies, the device must be disconnected from all voltage sources
and circuits if it is necessary to open the device. If an adjust-
ment, a maintenance task or repair is subsequently required
on the opened device while it is live, these must only be per-
formed by a specialist who is familiar with the associated
hazards and relevant regulations (VDE-0100, VDE-0701, VDE-
0683).
• Capacitors in the device may still be charged, even when the
device has been isolated from all voltage sources and circuits.
4
actual measured value in the large display. With the COMP func-
tion, comparative measurements can be carried out, during which
upper and lower limit values can be entered. The MEM (Memory)
and RCL (Recall) functions allow up to 8 measurement results to be
stored or recalled. An Auto Power Cut Off function switches the
DMM into stand-by after approx.
12 minutes, to avoid draining the battery unnecessarily. The mul-
timeter can be switched on again by setting the rotary switch first
to "Off" and then to the desired position again.
The DMM can be used universally in the hobby area as well as in
industrial, education and other fields.
3. Safety information
• CE-identification: The VC 350E digital multimeter is EMC tested
and complies with guideline 89/336/EEC; in addition, it is AC
tested and complies with the low voltage guideline 73/23/EEC.
• This instrument is constructed and tested in accordance with
DIN 57 411 part 1/VDE 0411 part 1, safety precautions for elec-
tronic measuring instruments or IEC 1010-1 and left the factory
in sound, technically-safe condition. To maintain this condition
and to guarantee safe operation, the user must comply with the
safety instructions and warning notices ("Attention!" and
"Note!") contained in these directions for use. The following
symbols must be observed:
= Attention! Dangerous voltages! Danger to life!
= Read the user's manual
CAT II = Overvoltage category II
= Safety class II

7
• Before each change in measuring range the test probes must be
removed from the test object.
• Before each measurement check your measuring device and
instrument leads for damage.
• Only use the instrument leads which are enclosed with the mea-
suring device for measurement. No others may be used.
• To avoid electric shock, care should be taken that the test pro-
bes and the measurement connections (test points) are not tou-
ched during measurement, not even indirectly.
• The voltage between a chosen 4-mm socket of the instrument
and ground may not exceed 600 VDC/VAC rms.
• The measuring instrument should not be used in spaces or
under adverse environmental conditions, in which inflammable
gas, steam or dust are present or can occur. For the user's own
safety it is essential to prevent the measuring instrument or test
leads becoming damp or wet. Avoid operation in the immedia-
te vicinity of
a) strong magnetic fields (loudspeakers, magnets)
b) electromagnetic fields (transformers, motors, coils, relays,
contactors, electromagnets, etc.)
c) electrostatic fields (charges/discharges)
d) transmission aerials or HF generators
• Do not use the multimeter shortly before, during or shortly
after a thunderstorm (lightning strike!/high energy over-volta-
ges!)! Care should be taken that hands, shoes, clothing, the
floor, the measuring instrument and test leads, switches and cir-
cuits etc. are absolutely dry.
6
• When effecting replacements, you must ensure that only fuses
of the specified type and the specified current rating are used.
The use of patched fuses or bridging of the fuse socket is not
permissible. To change the fuses, disconnect the measuring
device from the circuit and switch it off. Remove all connected
leads and test probes. Select a suitable cross-head screwdriver
and carefully open the housing. In addition the sockets cover
must be removed. The disassembly of the sockets cover is descri-
bed with diagram under "5.1.1 Battery replacement". Remove
the defective fuse(s) and replace with fuse(s) of the same type
and current rating..
0,8 F 250.8 A/250 V or F800 mA/250 V or, for the A range, 20 A
quick-acting 250 V; standard designation: F 0.8 A/250 V or
F800 mA/250 V or, for the A range, 20 A quick-acting 250 V;
standard designation: F20 A/ 250 V.
When the fuse change has been completed, carefully close and
bolt the housing in the reverse order.
Only use the measuring device when the housing has been safe-
ly closed and bolted.
• Take particular care when dealing with voltages greater than 25
V alternating (AC) or greater than 35 V direct voltage (DC). Even
at these voltages you can receive a lethal electric shock if you
touch electrical conductors.
Therefore, first of all switch off the current of the voltage sour-
ce, connect the measuring device to the connections of the vol-
tage source to be measured, set the required voltage measuring
range on the measuring device and then switch the voltage
source on again.
After the measurement has been completed, switch off the vol-
tage source and remove the instrument leads from the voltage
source connections.
• Before each voltage measurement ensure that the measuring
device is not located in the current measuring range.

9
2c COMP This button switches on the comparison measure-
ment function.
2d Blue button for switching from the measurement of DC to
AC units (while measuring V, uA, mA and A) or also, in the
switch position " / ", from diode test to acoustic conti-
nuity checking.
2e REC With this button the Auto-Hold function "A-H" and
the minimum (= MIN) and maximum (= MAX) value
memory is switched on.
2f R-H With this button it is possible a) to leave the function
under 2e or b) to switch off the automatic ranging and set
the desired measurement range by hand or c) to change set
values downwards.
2g MEM With this button, up to 8 different measurement
results can be stored independently of the measurement
function (V, A, etc.). The values in memory are, however, era-
sed as soon as the measuring instrument is turned off.
2h RCLL With this button, measurement results stored under
"MEM" can be called up consecutively.
3. Rotary switch for setting the different operations (voltage mea-
surement, current measurement, etc.)
4. 20 A input
This measurement input is protected with a 20 A fuse and is
intended for DC and AC currents up to 20 A max.
5. uA / mA input
This input is for measuring direct and alternating currents up to
max. 400 mA.
8
• When safe operation is thought no longer possible, the instru-
ment should be placed out of service and unintentional opera-
tion prevented. It is to be assumed that safe operation is no lon-
ger possible, if
- the device shows visible signs of damage,
- the device no longer functions and
- after extended storage under adverse conditions
or
- after severe transportation stress.
• Never switch the measuring device on immediately after it has
been brought from a cold into a warm area. The resulting con-
densation water could damage your device. Allow the instru-
ment to reach room temperature before switching it on.
4. Description of the operating elements
Figure see fold-out page side
1. 3 3/4-position LCD (liquid crystal display), reading 3999 max.
(4 1/2-position with frequency measurement; resolution 19999
max.; with 4 1/2-position "small" displays). Analogue bar graph
display, various measurement units and symbols.
2. Pushbutton area for special-function buttons
2a Yellow button for switching from current measurement (mA
or A) to temperature measurement (°C from mA; °F from A).
With the button in the switch position " / " fuses
("FUSE") can also be tested.
2b REL With this button, on the one hand the reference
value measurement is switched on and on the other hand
set values can be adjusted upwards.

11
Attention!
Do not in any event operate the measuring device when it is
open! Danger to life!
Do not leave used batteries in the measuring instrument, becau-
se even leak-proof batteries can corrode and thereby release che-
micals, which are both damaging to health and can destroy the
battery compartment. Used batteries are to be regarded as waste
requiring special handling and so do not belong with general
refuse. Used batteries must be disposed of in an environ-mental-
ly-friendly manner at suitable collection points (specialist trade or
scrap recovery yard).
5.1.2 Fuse testing
Note
Two fuses are built into the measuring instrument, an 800 mA
fuse for the current measurement range up to 400 mA max. and
a 20 A fuse for the current measurement range up to 20 A max.
Both fuses are quick-acting. Changing a fuse is described under
"3. Safety regulations".
9V Battery
Fuse
20 A 250 V
10
6. COM (-) input socket (COM- or negative connection)
7. V-Ohm-(+) input socket (= positive connection)
8. Capacity or temperature measurement socket. Using this socket
(uncharged!) capacitors and also temperatures (using the avai-
lable optional NiCrNi probe) can be measured.
9. RS-232 interface for the connection of an interface cable for
data transfer to an IBM compatible Windows 95 PC.
5. Using the multimeter
5.1Fitting the battery – changing the battery and
testing the fuses
5.1.1 Fitting the battery – changing the battery
In order for your measuring device to function perfectly, it must be
fitted with a 9V dry cell battery. When the battery change symbol
appears in the display the battery must be replaced. To do this,
proceed as follows:
Disconnect the measuring instr ument from the circuit being mea-
sured, remove the test leads from the instrument, switch it off,
remove the holster (if present) and loosen the two captive fixing
screws on the underside of the case with a suitable screwdriver.
Now carefully remove the sockets cover (if necessary with a thin-
bladed screwdriver). In addition note the following diagram. Dis-
connect the used battery from its connecting clip and replace the
battery with a fresh one of the same type. Remember to push the
sheath, if present, onto the battery again.
After successfully replacing the battery place it in the battery com-
partment and carefully close this once more. Take care that the
connecting clips leads do not become crushed.

13
Attention!
Never exceed the input levels, as in this can cause damage to the
measuring device, and can endanger the user.
5.4 Positioning the measuring instrument (sloping position) or
position of use Always operate the multimeter so that the
liquid crystal display (LCD) can be read and the digital
display is facing upwards. There is a fold-out bracket on the
rear of the instrument for better readability in upright
operation.
5.4 Commissioning
5.4.1 Basic settings
The measuring instrument is switched on by turning the rotary
switch to the desired measurement function. "Normal" measure-
ments can now be carried out without additional functions.
To select such an additional function, operate one of the buttons
in the button panel.
5.4.2 Connector & socket configuration and switch markings
a)Connector for capacity and temperature measurement (polari-
sed "+" and "-")
Place a (discharged!) capacitor correctly polarised in the sockets.
Ensure that the connections are long enough, because other-
wise incorrect measurements can occur.
For temperature measurement plug the connections of a K-type
thermocouple element (NiCrNi) with the correct polarity into
the marked sockets.
b)Type of operation switch = measurement function switch (10)
12
The measuring instrument has a special function which enables
the built-in fuses to be checked before each measurement for
soundness (whether "blown" or intact). For this, proceed as follo-
ws:
- Position the rotary switch to " / " (Continuity check/Diode
test)
- Press the yellow button once. The word "FUSE" appears in the
display.
- Connect "only" the red measuring lead to the V/Ohm/F socket
of the multimeter.
- Touch the metal insert of (deep within) the uA/mA socket with
the probe). Should an acoustic signal sound and the bar graph
indicate a minimum, the fuse (800 mA, quick-acting) is in
order. In case not, the fuse is defective. In this case, replace the
fuse with new.
- Next, touch the metal insert of (deep within) the A socket with
the probe). Should an acoustic signal sound and the bar graph
indicate a minimum, the fuse (20A, quick-acting) is in order. In
case not, the fuse is defective. In this case, replace the fuse
with new.
5.2 Connecting the instrument leads
Always use only the supplied measuring leads for making measu-
rements. Before each connection note the condition of the
connecting plug and test prods and check the insulation for dama-
ge. These measuring leads are intended for voltages up to 1500 V
max. The measuring instrument, the VC 350E is designed for vol-
tages up to 1000 VDC or 750 VAC rms max. Take particular care
when dealing with voltages greater than 25 V AC or 35 V DC.

15
Switch to temperature measurements with yellow
button
A/TEMP°F = DC and AC current measurements up to 20 A max.
or temperature measurements in °F, Auto-Range
and manual range selection possible; Switch to
temperature measurements with yellow button
c) 20A socket
For DC or AC current measurements up to 20 A max. (!), the red
measuring lead must be plugged in here.
Attention!
The measuring function switch must not on any account be posi-
tioned on voltage measurement (mV or V) during current measu-
rement.
d) mA socket
The red instrument lead should be plugged in here for direct
or alternating current measurements up to 400 mA max., but
only if the measuring function switch is set to "4mA" or
"400mA".
e) COM = common socket
the black measuring lead must be plugged in here for all mea-
surements except temperature and capacity measure-ments
(common socket means minus "-" or ground socket)
f) V/Ohm socket
the red measuring lead must be plugged into this socket to
carry out voltage, frequency or resistance measurements, con-
tinuity checks or diode tests.
14
Attention!
The type of operation switch may not under any circumstances be
moved during measurements, because otherwise the measuring
instrument can be destroyed and it can endanger the user's life.
Arranged in the full circle, the different measuring ranges can be
selected by turning the switch:
OFF = switch the measuring instrument off when measu-
rements are completed
V = Volt AC/DC Both Auto-Range and manual range
selection (R-H) is possible
mV DC = millivolt DC (milli = 10 exp.-3) only a mV DC volta-
ge range up to 400 mV max.
Ohm = resistance measurement range; both Auto Range
and manual range selection (R-H) possible
"/" = continuity check / diode test - no Auto Range and
no manual range selection possible, switch to the
respective function with the "blue" button FREQ =
frequency measurement - no manual range selec-
tion (with R-H) possible
CAP = uA= uA AC/DC measurement (u = micro = exp.-6),
Auto Range and manual range selection possible
uA = uA AC/DC measurement (u = micro = exp.-6), Auto
Range and manual range selection possible
mA/TEMP°C = mA AC/DC or temperature measurements in °C,
Auto Range and manual range selection possible;

17
- As soon as the test probes are removed from the measurement
point, the small display returns to "0000", while the set refe-
rence value remains visible in the main display.
D) COMP (= Comparison)
In this sub-function, a high/low comparison can be carried out, in
which the highest and lowest stored reference value can be com-
pared with the present measured value.
The main (large) display shows "Lo", when the present measured
value is smaller than the lowest stored (preset) reference value.
"Hi" is displayed when the present value is greater than the hig-
hest stored reference value. When the present measured value lies
between the upper and lower set limits, "Pass" is displayed. The
actual measured value is given in the small display. This function is
not available for frequency, capacity or temperature measure-
ments. To use this function, proceed as follows. There are two
methods to input or set the comparison values.
Possibility 1:
D1) As under reference value measurement, the range in which
the comparison measurement is to be performed must first be
set; For this, press the "R-H" button until the desired measu-
rement range is set.
D2) Then, press the button "COMP" until the rightmost digit in
the main display flashes. Should the button be pressed only
briefly, instead of the set mode "Err" (Error) appears in the
display. In the small display "Hi" (High = upper comparison
value) appears.
D3) Now set the desired upper limit for this digit with the buttons
" REL" and " R-H" Then, press the "COMP" button once
more.
16
5.4.3 Display-explanation and symbols
A) Digital display
The display can display up to "4000" and (-) polarity is auto-mati-
cally indicated (for negative voltages or reversed polarity). There
are also three decimal point positions.
B) Analogue bar graph
The analogue bar graph consists of 43 segments. It has a slightly
higher measuring speed than the digital display. This enables mea-
sured value trends to be more easily recognised, as with an analo-
gue multimeter, but without its mechanical disadvantages (dam-
ping of the measurement indicator).
If the measurement range is exceeded, then "OL", for Overload, is
displayed.
C) REL (= Relative)
This function enables so-called reference value measurements, in
that the present measured value is displayed in the "small" display
and the difference in the main display. This function is not availa-
ble under frequency measurements, diode tests, continuity checks
and temperature measurements. Additionally, manual range sel-
ection "R-H" must be used for "REL" measurements rather than
"Auto Range". To set a reference value, proceed as follows:
- Select the range in which the reference value is to be used; in
addition press the button "R-H" until the desired measurement
range is set.
- Measure for example under voltage measurement a DC voltage
(a battery) of 1.5V. While measuring, press the "REL" button.
The reference value (1.5 V) is now set. Now perform the volta-
ge measurement in comparison with the reference value. The
present measured value at the measurement point is displayed
in the small display, while the difference between the set refe-
rence value and the present measured value is displayed in the
main display.

19
Possibility 2:
D1) Carry out steps D1) and D2) in "Possibility 1". Then touch with
the test probes the point to be measured, the value of which
is to be set as the upper limit (Hi).
Press the button " REL" until the desired value is displayed
in the main display. At the same time the rightmost digit
remains flashing. Now remove the test probes from the points
of measurement. Press the "COMP" button four times, until
"Hi" disappears from the small display and instead "Lo"
appears.
D2) Connect the test probes to another point to be measured ,
which is to be set as the lower limit (Lo). Now press the " R-
H" until the desired value appears in the main display. Here,
too, the rightmost digit remains flashing. Remove the test
probes from the (second) point to be measured. Press the
"COMP" button four times, until "Lo" disappears from the
small display and the comparison measurement begins. In the
absence of an applied measurement signal, "Lo" is displayed,
with in addition "0000" in the small display. Under resistance,
diode test and continuity check measurements "Hi" appears
in the main instead of "Lo". In the small display "OL" (Over
load) appears instead of "0000".
D3) Connect the test probes to the measurement point, the value
of which is to be set as the comparison measurement value. If
the present measured value shown in the small display is
lower than the set lower comparison value, then "Lo"
appears in the main display. If the present measured value lies
above the set upper comparison value, "Hi" appears in the
main display. If the present measured value lies between the
set upper and lower comparison values, "Pass" appears in the
main display.
D4) To be able to leave the function, the measuring instrument
must first be removed from the measurement circuit and the
rotary switch then moved to another switch position.
18
D4) The next-left digit flashes. Proceed as described in c) until the
whole "Hi" comparison value is set.
D5) Press the yellow button once "COMP". The upper limit value
"Hi" is stored in memory, "Hi" disappears from the small dis-
play and "Lo" (Low = lower comparison or limit value)
appears in its place. Once again the rightmost digit flashes.
D6) Carry out the setting of the lower limit values as described in
c. Then, press the "COMP" button once again. The comparison
measurement begins. In the absence of an applied measure-
ment signal, "Lo" is displayed, with in addition "0000" in the
small display.
Under resistance measurement, diode test and continuity
check, "Hi" appears in the main display instead of "Lo". In the
small display "OL" (Overload) appears instead of "0000".
D7) Connect the test probes to the measurement point, the value
of which is to be set as the comparison measurement value. If
the present measured value displayed in the small display is
lower than the lower comparison value set, then "Lo"
appears in the main display. If the present measured value lies
above the set upper comparison value, "Hi" appears in the
main display. If the present measured value lies between the
upper and lower comparison values set, "Pass" appears in the
main display.
D8) To be able to leave the function, the measuring instrument
must first be removed from the measurement circuit and the
rotary switch then moved to another switch position.
Note
Negative measured values cannot be set.

21
Note
The measurement values are reproduced as they were stored (e.g.
voltage values in "V" while in resistance measurement), indepen-
dently of the measurement function setting.
F) R-H (= Range Hold)
In this function the automatic range selection (Auto Range) can be
switched off and the measurement range set by hand (manually).
The "AUTO" symbol disappears from the display as soon as the
button is first pressed. With each further press of the button
" R-H" the decimal point is shifted one position to the left or
right and the units of measurement change correspondingly.
To leave this function press the " R-H" button until "AUTO" is
displayed in the upper display strip again.
G)Auto Hold - MIN - MAX function
The "Auto-Hold" function enables a measurement value to be
"frozen" / held for later use, e.g. in measurement processes. With
the MIN function, the lowest measurement value appearing is
automatically stored. With the MAX function, the highest measu-
rement value appearing is automatically stored. The special func-
tion(s) is(are) not useable under temperature, capacity or fre-
quency measurements. While using the special function, the
"Auto Range mode" (automatic range selection) is in addition not
active.
It is therefore necessary to set a specific measurement range for
this special function beforehand. While using a special function,
this becomes abandoned if the measurement range is changed
manually. To set / activate the special function, proceed as follows:
G1) Connect the red test lead to the respective measurement
socket (but not "COM") of the measurement function with
which the "Auto Hold MIN-MAX" function is to be used.
Connect the black test lead to the "COM" socket.
20
E) MEM (= Memory) and RCLL (= Recall)
With this special function, except under temperature t mea-
surement, up to 8 reference values can be stored
and called up / reproduced. Measurement values of different
measurement functions can also be stored, such as DC volta-
ge in Memory 1, resistance in memory 2 and so on. To do this,
proceed as follows:
E1) Performing measurements. Each time a certain value is to be
stored, no matter in what measurement function (except tem-
perature measurement), press the "MEM" button. As a result,
two numerals separated by a space appear in the small dis-
play. The left one shows the memory location at present being
reproduced ("0" when "RCLL" button not yet pressed), the
right one shows the verifiable / specifiable memory locations.
E2) When the first measurement value has been stored by pres-
sing the "MEM" button, this is verified by the number "1". Up
to eight (8) measurement values can thus be stored. When all
memory locations are filled, the number 8 is displayed on the
right in the small display.
E3) When one of the eight stored values is now to be used, the
"RCLL" button must be pressed. Every time the "RCLL" button
is pressed, the next-higher memory location opens.
The stored measurement value is thereby read out. The
memory location currently being read is given in the left row
of numbers from 1 to 8.
E4) To be able to leave the Store/Recall function without losing
the stored values, turn the rotary switch, but not to "OFF". To
erase the stored values, either press the "MEM" button or
turn the rotary switch to "OFF".

23
Note
So that under resistance measurement, diode test and continuity
check a "MIN" measurement is possible at all, either the test pro-
bes must be held together ("short-circuited") or a resistance mea-
sured. Only then can the "REC" button be pressed, and only then
does the symbol "A-H" disappear from the display, or only then
does the symbol "MIN" appear in the display. When "MIN" is visi-
ble, normal measurements (under resistance measurement, conti-
nuity check and diode test) can be proceeded with. This procedu-
re is not required with other measurements.
Now connect the test probes to the circuit (points) to be mea-
sured. The present measured value appears both in the large
and small displays. Now remove the test probes from the test
points. The most recently measured value remains frozen
(held) in the large display. In the small display, "OL" appears
under resistance measurement, continuity check and diode
test. "0000" appears in the small display under the other mea-
surement functions. The measurement value now remains
frozen/held in the large display until a smaller value is esta-
blished during a further measurement. The large display
always displays the smallest occurring measured value.
G6) When the MAX function is to be used and the instrument is in
the "MIN" function mode, press the "REC" button once
again. The "MIN" symbol disappears and in its place the
"MAX" symbol appears to its left. When, however, the instru-
ment is at present in "Auto Hold" mode, press the "REC" but-
ton twice. When the "Auto Hold" mode is also deactivated,
the REC" button must be pressed three times.
22
G2) Set the rotary switch to the desired measurement function
(but not to one of those mentioned as not available).
G3) Switch off the "Auto Range" function while setting the desi-
red measurement range by hand (= manually) with the but-
ton.
G4) When the Auto Hold function is now to be used, press the
"REC" button. The symbol "A-H" appears in the so-called
headline of the display. "0000" appears in the small display
and in the main display, independently of the range setting.
With the measurement functions diode test, resistance mea-
surement and continuity check, "OL" for overload or overrun
appears in the small and large displays instead of "0000".
Connect the test probes to the circuit to be measured. The
present measurement value appears both in the small and
large displays. Now remove the test probes from the points of
measurement. In the large display the most recently measu-
red value remains frozen / held. In the small display, "OL"
appears under resistance measurement, continuity check and
diode test. Under the remaining measurement functions
"0000" appears in the small display.
When a new measurement is now made, the value displayed
in the large display remains held for another approx.
4 seconds, before it disappears or a new measurement value
is displayed.
G5) When the MIN function is to be used while the "Auto Hold"
function is presently in use, press the "REC" button once
again. The symbol "A-H" for Auto Hold disappears from the
headline as a result and in its place the symbol "MIN" appears
beneath. When however the "MAX" mode is presently in use,
or the "Auto Hold" mode is not in use, the "REC" button must
be pressed twice.

25
The setting / changing of the respective alternate value is
done with the " REL" or " R-H" button. Having successfully
made the setting, press the yellow button again.
H2) To activate (switch on) the printer port, before switching on
the measuring instrument (by means of the rotary switch) the
"REC" button and the yellow button must be pressed. After
approx. 2 to 3 seconds release the yellow button, but conti-
nue to press the "REC" button. Now switch on the measuring
instrument and the computer. The printer port is activated.
Every 10 seconds, the measurement data with measured
value, measurement range and measurement unit will now
be printed out via the connected serial printer. To switch the
printer port off again, position the rotary switch to "OFF".
H3) To switch off the Auto Power Off function, before switching
the measuring instrument on (by means of the rotary switch),
press the blue button. After approx. 2 to 3 seconds release the
blue button and immediately afterwards, switch the measu-
ring instrument on by means of the rotary switch. The mea-
suring instrument will now not switch off after approx. 13
Min., but rather remain operating until either the battery is
empty (used up) or the rotary switch is set to "OFF" (instru-
ment off). If the measuring instrument is switched off by
means of the rotary switch and afterwards switched on again,
the Auto Power Off function is reactivated, i.e. the instrument
switches off automatically after 13 minutes.
5.4.4 Display information or symbols about the operating modes
a) Battery change indicator
An alkaline 9V battery in this measuring instrument lasts on
average approx. 400 hours. Approx. 8 hours before the battery
"expires", the battery change symbol appears in the display.
+-
24
Note
The "MAX" measurement procedure is similar to the "MIN" mea-
surement. Proceed as described in "Note" under "MIN" measure-
ment.
Now connect the test probes to the circuit (points) to be measu-
red. The present measured value appears both in the large and
small displays. Now remove the test probes from the test points. In
the large display the most recently measured value remains "fro-
zen" (held). In the small display, "OL" appears under resistance
measurement, continuity check and diode test. "0000" appears in
the small display for the other measurement functions. The mea-
surement value now remains frozen/held in the large display until
during a further measurement a higher value is established. The
large display always displays the highest-occurring measured
value.
H) "Device on" special functions
When the instrument is switched on, various special functions can
be activated. For example the "measurement frequency" for alter-
nating current - or AC voltage measurements can be changed
from 50 Hz to 60 Hz and vice versa. It is also possible to connect a
serial printer and to activate the printer port by means of the
"Device on" function. With the last of the three "Device on" spe-
cial functions, the "Auto Power Off" function (automatic switch-
off after approx. 13 minutes) can be turned off. When one of
these special functions is to be activated, proceed as follows:
H1) To be able to change the measurement frequency, the yellow
button must be pressed and held when switching on the mea-
suring instrument (by means of the rotary switch) and relea-
sed after approx. 2 to 3 seconds. As a result "50 Hz" or "60
Hz" appears in the display according to the previous setting.

27
Cause Remedy
Measuring instrument Read through the operating
not operating instructions thoroughly.
Is the battery unused?
The battery is in order, but Are the fuses in order?
no current measurement Check the fuse(s) per 5.1.2. Are the
possible fuses clipped in the holder(s)?
6. Performing measurements
General:
The multimeter is not protected against the test leads being
connected to the wrong measuring socket as a function of the res-
pective measurement function. It can be damaged or destroyed.
To safeguard against this, a so-called acoustic socket alarm is built
into this multimeter, which together with the selected measure-
ment function (voltage, frequency, resistance or capacity measure-
ment, etc.) reproduces various signal sequences. If for example the
red test lead is in one of the current measurement sockets (uA/mA
or A) and the black test lead in the COM socket but the rotary
switch is not set for current measurement, then the following
acoustic signals are hear:
V AC/DC : ——————— (continuous tone)
mV DC/FREQ : - - - - - - - - ("slowly"-interrupted tone)
Ohm / /->l- : - - - - - - - - - - - ("quickly"-interrupted tone)
CAP : (no acoustic signal)
Note
Should other test leads be used instead of those supplied with
the measuring instrument, the socket alarm does not function.
26
Between each individual measurement cycle, a battery check is
carried out.
b) All other symbols, which stand for the various units of measu-
rement:
AC = Alternating Current
DC = Direct Current
mV = Millivolt (exp.-3)
V = Volt
uA = Micro-Ampere (exp.-6)
mA = Milliampere (exp.-3)
A = Ampere
kHz = Kilohertz (exp.3)
MHz = Megahertz (exp.6)
°C = Degrees Celsius
°F = Degrees Fahrenheit
uF = Microfarad (exp.-6)
nF = Nanofarad (exp.-9)
kΩ= Kiloohm (exp.3)
MΩ= Megaohm (exp.6)
5.5 Fault finding
If the multimeter is not functioning correctly, the following causes
may be responsible:

29
Each of the voltage ranges, whether AC or DC, possess an input
impedance of 10 MOhm in parallel with < 100 pF). The AC volta-
ge input is AC-coupled. As soon as a "-" appears in front of the
measured value in a direct voltage measurement, the measured
voltage is negative (or the instrument leads are switched).
Notes
-Due to the fact that the measurement input is very sensitive, it
may be that certain measured values are displayed even with
test leads unconnected (not connected to a circuit). This occur-
rence is normal and will disappear as soon as measurements are
performed.
- In the "mV DC" measurement range, no "Auto Range" (auto-
matic range selection) is available.
6.2 Current measurement
To measure direct or alternating currents, procedure is as follows:
1. Connect the red test lead to the A or uA/mA socket and the
black test lead to the COM socket.
2. Position the rotary switch to current measurement (uA, 4000 uA
max.; or mA, 400 mA max.; or A, 20 A max). In the current mea-
suring range both automatic ("Auto Range") and manual range
selection ("R-H") is possible.
3. Press the blue button according to whether DC or AC current is
now to be measured. As soon as "AC" appears in the display,
alternating current mode is selected.
4. Open the unpowered circuit to be measured (switch off circuit
to be measured) and connect the test lead(s) in series with the
unpowered circuit to be measured (see following diagram).
28
6.1 Voltage measurement
Attention!
The maximum permitted input value must not be exceeded under
any circumstances. MAX. 1000 VDC or max. 750 VAC rms.
Do not touch any circuits or circuitry components when measu-
ring voltages higher than 25 VACrms or 35 VDC. The measuring
instrument may only be used in installations of Overvoltage cate-
gory II.
To measure direct or alternating voltages, the procedure is as fol-
lows:
1. Connect the red instrument lead with the V/Ωsocket and the
black instrument lead with the COM socket.
2. Set the rotary switch to the desired position (V) or, only for DC
voltage measurements, also to "mVDC".
3. Press the blue button according to whether DC voltage or AC
voltage is to be measured (except for mV DC). As soon as "AC"
appears in the display, the instrument is in AC measurement
mode.
4. Connect the test probes with the test object (load, circuit, etc.).
Attention!
Because the metal inserts of the socket contacts sit relatively dee-
ply (on grounds of safety), it is imperative that the measuring
lead plugs are inserted into the respective sockets up to their
stops. Make sure that the test lead plugs are securely connected
to the measuring instrument before a supposedly "0V" measure-
ment has been performed and circuit components then touched.
Attention!! Life can be endangered if volt
ages of more than 25 VAC rms or 35 VDC are touched.

31
symbols appear in the display: "OL", " " and "Ω". Should the
symbols not appear, press the blue button once.
3. Then connect the test probes with the absolutely voltage-free
test points.
Depending on the circuit resistance present, the following acou-
stic signals are heard:
————————— (continuous tone) with 30 Ohm or less
— — — — — — — ("quickly"-interrupted tone) with more than
30 Ohm and less than 106 Ohm
————- ———- ("slowly"-interrupted tone) with more than
106 Ohm and less than 1700 Ohm
Attention!
Do not measure charged capacitors, as a possible discharge may
damage your measuring device.
The indicated measured value is not the "true" resistance value.
To establish this, a resistance measurement must be carried out
(as follows).
6.4 Resistance measurement
Attention!
Ensure that all circuitry components, circuits and structural ele-
ments to be measured, as well as other test objects, are comple-
tely voltage-free.
For measurement of voltage-free resistance up to max. 40 MOhm
proceed as follows:
30
5. Power up the circuit to be measured (circuit, power, etc.) and
read the measured current. Whenever a "-"appears in front of
the measured value, this indicates a direct current or the mea-
sured value is negative or the test leads reversed.
Attention!
Do not measure any currents in circuits in which voltages greater
than 250 VDC or VAC rms can occur, so that the measuring device
is not damaged and your life is not endangered as a result. Under
no circumstances should currents over 20 A be measured. Measu-
rements should only be made in 16 A-fused current circuits or
those in which powers greater than 4000 VA cannot occur.
Measurements of currents equal to 20 A must only be measured
for a maximum of 10 s duration and must only be performed in
intervals of 15 minutes (cooling down phase for the shunt).
6.3 Continuity checking and diode test
With this function voltage-free leads, fuses, circuits etc. can be
acoustically checked for continuity. This measurement is per-for-
med as follows:
1. Connect the red instrument lead with the V/Ωsocket and the
black instrument lead with the COM socket.
2. Position the rotary switch to / . As a result the following
ADMM
Consuming
device,
load, circuit
Current
source

33
3. Now connect the test probes to the test points, an unpowered
semiconductor circuit, with the red probe to the anode and the
black probe to the cathode (these usually being indicated by a
coloured ring, spot or similar).
To check a diode path in the conducting direction, a voltage of
approx. 0.25 V (germanium) or 0.7 V (silicon) will be measured,
provided that the diode path is not defective.
When the test probes are reversed, i.e. red to the cathode and
black to the anode, then the high resistance direction of the
diode path will be checked.
If "OL" is displayed, the diode is serviceable. If on the contrary
a value between 0 V and "OL" is displayed, either the test points
have been incorrectly chosen or the diode is faulty.
The test voltage under diode test is sufficient to cause most (low
current) LEDs to emit light. With LED operating voltages of
more than 2.0 V, however, the DMM can incorrectly indicate
that the LED is faulty.
Attention!
During the diode test, ensure that the diode and circuit in which
it is installed are completely voltage-free. Any capacitors must be
discharged.
6.6 Frequency measurement
Attention!
It is essential to observe the max. input levels!! Do not connect
any voltages greater than 250 VDC or VAC rms max. With volta-
ges greater than 25 VAC or 35 VDC, there is danger to the user in
the event of contact.
32
1. Connect the red instrument lead with the V/Ωsocket and the
black instrument lead with the COM socket.
2. Position the measurement function switch to resistance measu-
rement (Ohm).
3. Then connect the test probes with the absolutely voltage-free
test points. Auto Range sets the appropriate measurement
range, to produce the smallest possible measurement error.
The resistance of the test leads can normally be ignored (approx.
0.1 to 0.2 Ohm). However, even this low value can lead to inaccu-
racies in the 400 Ohm measurement area. To compensate for these
"measurement errors", the REL function (described under 4.4.3.C)
can be used.
When resistance measurements are performed, take care that the
test points which are to be touched with the test probes are free
from dirt, oil, solder flux or similar. Such conditions can falsify the
measured value.
With resistances greater than approx. 4 MOhm the display can
take some time to become stabilised. As soon as "OL" appears in
the display and the bar graph flashes, the measurement range has
been exceeded, or the circuit being measured is open circuit/high
resistance (> 40 MOhm).
6.5 Diode test
For measurement of unpowered semiconductor circuits (diodes,
transistors, rectifiers, etc.), proceed as follows:
1. Connect the red test lead to the V/Ω socket and the black test
lead to the COM socket.
2. Set the rotary switch to " / " and press the blue button
once. The following symbols are shown in the display: The diode
symbol "->l-", "mV" and "OL" (for overload or here: "infinite-
ly-high resistance"). Manual range selection is not possible.

35
To measure the capacity of capacitors, proceed as follows:
1. Discharge every capacitor, before connecting it to the measu-
ring instrument. Do not measure charged capacitors, otherwise
the measuring instrument can be damaged.
2. Set the rotary switch to "CAP".
3. Measurements can now (only) be performed with the connec-
tors on the measuring instrument. With polarised capacitors,
observe the correct ("+" and "-") polarity. Take care that
connecting "legs" are sufficiently long and not too thin (weak).
Should the "legs" be too short and thus not be in contact or if
the capacitor is faulty, a capacity of approx. 00.11nF is display-
ed.
6.9 Temperature measurement
The temperature display ranges from -40°C to +1000°C, that is
from -40°F to 2000°F, with the optionally-available measuring
probe. Temperature measurement is carried out exclusively with a
K type (NiCrNi) thermocouple. When no temperature probe is
connected to the measurement socket on the measuring instru-
ment, the present room temperature (ambient temperature. To
perform a temperature measurement, proceed as follows:
1. Position the measurement function switch either to "mA/
TEMP°C" or "A/TEMP°F" and press the yellow button once.
2. Connect the thermocouple plug, correctly polarised (narrow
and wide contact blades) to the CAP/TEMP measurement
socket.
34
While measuring system voltages greater than 25 VAC or 35 VDC,
do not move the rotary switch to another measurement func-
tion). The sensitive electronics within the measuring instrument
can otherwise be destroyed, as a result of which the user can be
endangered.
To measure a frequency, proceed as follows:
1. Connect the red test lead to the V/Ω socket and the black test
lead to the COM socket.
2. Position the rotary switch to "FREQ".
3. Connect the test probes to the points to be measured (genera-
tor output, etc.).
Note
To perform a measurement with maximum accuracy, use a BNC
screened cable where possible (adapter available) for the measu-
rement, to avoid error measurements caused by radiated fields.
For frequency measurement, it is not possible to use manual range
selection!
6.7 Capacity measurement
Attention!
When short-circuiting capacitors, high-energy discharges can
occur. Attention - danger to life! Do not touch the connectors of
capacitors with voltages over 35 VDC or 25 VAC. Take care in spa-
ces in which dust, inflammable gas, steam or liquid is present or
can occur. ==> Danger of explosion!

37
3. Click on the "START" (bottom left, on the taskbar) with the
left mouse button: and then click on "RUN".
4. As a result, a dialog box appears into which "A:\Setup.exe"
should be entered. Click on OK". Follow the on-screen setup
program instructions.
5. Once the program has successfully loaded, click on "OK".
Step 2
The software for Windows 95 is now loaded. To "communicate"
with the multimeter, the following inputs/actions are now requi-
red:
a) Connect the interface lead 4-pin plug (supplied) to the RS-232
interface on the (switched off) measuring instrument. Connect
the other end of the interface lead to a free serial port on the
(switched off) computer.
b) Power up the PC. Open the START window under Windows ‘
95. Click the mouse pointer on the Programs menu item using
the left mouse button. Among others in the sub-directories
listed is "DMM97". Click on OK „97". Thereupon "About
Scope View" is displayed. Click on OK.
c) The menu "Scope View Main Menu" is displayed. To install or
change the hardware configuration, click on "Setup". "Scope
View Setup" appears on-screen. Enter the following infor-
mation:
Meter Model 350E
Com Port COM1, COM2, etc. (communications interface
on the PC)
Baud rate 1200 (transfer speed 1200 bits per second)
d) Having inputted the data, store the data "permanently" by
clicking on "SAVE" and then on "CLOSE" to close the window.
36
Attention!
Do not connect any voltages. The instrument can be destroyed by
this.
6.10 Using the analogue bar graph
The bar graph is easy to operate and understand. It is comparable
with the pointer of an analogue measuring instrument without its
mechanical disadvantages. It is particularly suitable for measuring
signals that change rapidly, for which the digital display is too
"slow". So the trends of a measured value change can be quickly
recognised and evaluated.
6.11 Using the multimeter in connection with a com-
puter
The multimeter is supplied together with a diskette, on which is
software for DOS and Windows 95 operation. So that the measu-
ring instrument can communicate with an IBM compatible PC, the
software must first be installed.
Note
The following installation(s) presuppose basic knowledge of the
various MS DOS commands and an available hard disk. Read the
MS DOS manual with regard to software installation, if you have
no or insufficient basic knowledge of MS DOS commands. In addi-
tion, a VGA monitor (+ VGA card in the computer) is required to
operate the software.
Step 1
1. Start your computer and activate Windows. Windows 95 (nor-
mally) loads automatically.
2. Under Windows, insert the floppy disk into the 3.5" drive (A
or B according to the installation).

39
Notes
Should there be no hard disk available, it is possible to start
the program from the floppy disk: Change to the drive in
which the floppy will be run.
Change to the "DOS"subdirectory on the floppy, type "DMM"
and press Enter.
To stop the program, or if an "ERROR"occurs, perform a warm
boot (Control, Alt, Del keys).
Step 4
The following defines the communication parameters.
Transfer rate : 1200 baud
Character code : 8-bit ASCII
Parity : none
Stop bits : 1
Step 5
The configuration of the measuring instrument interface is as
follows:
Data transfer between the measuring instrument and the
computer is bi-directional.
RXD
RS-232C
GND
TXD
DSR
RTS
38
e) To run the PC program, click on "OFF" in the bottom right of
the menu box.
Step 3
Use of MS DOS software is described below:
a) Switch on the computer and measuring instrument. The MS
DOS program is named METER.
Note
The following installation(s) presuppose basic knowledge of the
various MS DOS commands and an available hard disk. If in-ade-
quate or no basic knowledge of MS DOS commands is available,
refer to the MS DOS manual concerning software installation. In
addition, a VGA monitor (+ VGA card in the computer) is required
to operate the software.
1. Insert the floppy disk into the appropriate disk drive (A or B or
similar).
2. Make a directory on the hard disk (usually "C") with the name
"METER".
cd\ [Enter]
md METER [ENTER] [ENTER] = Press the "Enter" key.
3. Change to drive A (or B, etc., according to the installation). Call
the file METER and press ENTER key, e.g.:
cd METER
4. Copy the files from the floppy to the hard disk:
copy a:\DOS c:
5. In order to start the program, enter "DMM" and press "Enter".
After that, follow the on-screen instructions.
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