
Translation of the original 
operating instructions 

2  DRELLOSCOP 1020 
Article no. of this documentation:  1.1020.2B001e  
As of:        12.11.2012 
DRELLO is used in these operating instructions as abbreviation for 
DRELLO Ing. Paul Drewell GmbH & Co. KG. 
No part of this publication may be duplicated, transmitted, transcribed, 
stored to a memory device, translated into another language or computer 
language in any way without prior written permission from DRELLO. Infringement of this copyright can also compromise product support from 
DRELLO for this device. DRELLO reserves the right to make changes to 
the product described within this manual without advanced notice. The 
contents of the manual do not contain any contractual or other obligations 
on the part of DRELLO and are not legally binding. This publication was 
created with the utmost care. Suggestions for improvement can be submitted to DRELLO. 
© DRELLO Ing. Paul Drewell GmbH & Co. KG 
Andreas-Bornes-Strasse 46 
D-41179 Mönchengladbach 
Telephone:  +49 - (0)2161 - 909 - 6 
Telefax:  +49 - (0)2161 - 909 - 700 
Email:  info@drello.de 
Internet:  www.drello.de 

DRELLOSCOP 1020  3 
1  General  5 
1.1  Information on these operating instructions  5 
1.2  Explanation of symbols  6 
1.3  Warnings  7 
1.4  Limitation of liability  8 
1.5  Spare parts  8 
2  Safety  9 
2.1  General  9 
2.2  Responsibility of the operator  9 
2.3  Staff requirements  11 
2.3.1  Staff qualifications  11 
2.3.2  Unauthorised persons  12 
2.3.3  Instruction  12 
2.4  Intended use  13 
2.5  Device protection  13 
2.6  Particular hazards  14 
2.6.1  Danger from stroboscopic lig ht flashe s  14 
3  Technical specifications  15 
4  Description  17 
4.1  Description of functions  17 
4.2  Device overview  20 
4.2.1  Front view  22 
4.2.2  View from underneath  22 
4.3  Menu structure  23 
4.4  Type plate  24 
5  Transport, assembly and connection  25 
5.1  Scope of supply  25 
5.2  Available accessories  27 
5.3  Unpacking  27 
5.4  Storage  28 
5.5  Requirements for the place of use  29 
5.6  Mains operation  29 
5.7  Connecting an external controller  30 

4  DRELLOSCOP 1020 
6  Operation  31 
6.1  Switching the device ON/OFF  31 
6.2  Operating  31 
6.2.1  Selecting the operating mode  31 
6.3  Further setting options for flash operation (manual control) 33 
6.3.1  Setting the flash sequence display  33 
6.3.2  Displaying the current flash du ration  33 
6.3.3  Setting the "Duration-Auto-Modus" variable flash duration 34 
6.3.4  Setting the flash duration "Duration-Fix-Modus"  35 
6.4  Further setting options for flash operation (external control) 36 
6.4.1  Image shift (PHASE)  36 
6.4.2  Setting the slow-motion function  37 
7  Maintenance and repair  38 
7.1  Maintenance  38 
7.2  Changing the batteries  38 
7.3  Cleaning  39 
7.4  Troubleshooting  39 
7.5  Repairs  40 
7.6  Disposal  40 

DRELLOSCOP 1020  5 
1  General 
1.1  Information on these operating instructions 
These operating instructions contain important instructions on handling the DRELLOSCOP 1020 LED hand-hel d str obo sc ope, hereinafter referred to as the device, during installation, operation, 
maintenance and care as well as disposal. 
The requirement for safe, proper and economic work on and with 
the device is compliance with all spe cif ied safe t y and handlin g instructions. 
Compliance helps to avoid danger, minimise repair costs and 
downtimes and increase the reliability and the service life of the device. 
In addition, local accident prevention regulations and general safety 
rules for the location of the device must be complied with. 
Read the operating instructions carefully before beginning any 
work! They are part of the product and must be kept in the immediate vicinity of the device and be accessible to operating staff at all 
times. 

6  DRELLOSCOP 1020 
1.2  Explanation of symbols 
All warnings in these operating instructions are also indicated by a 
warning symbol. 
The following warning symbols are used throughout these operating instructions: 
Symbol  Meaning 
Danger of electric current 
General instructions and useful suggestions on 
handling 
Note on observing environmen tal regula tio ns 
for disposal 

DRELLOSCOP 1020  7 
1.3  Warnings 
The warnings used in these operation instructions are indicated by 
signal words that are intended to indicate the extent of the danger. 
The warning symbol also indicates the type of danger. 
The following warning symbols are used throughout these operating instructions: 
WARNING 
Risk of injury! 
Consequences of failure to observe... 
► Instructions for avoidi ng 
A warning of this category indicates a potentially dangerous situation. If the dangerous situation is not avoided, it may lead to serious 
injury or even death. 
Follow the instructions in this warning to avoid possible danger of 
serious injury or even death. 
 CAUTION 
Damage to property by... 
Consequences of failure to observe... 
► Instructions for avoidi ng 
This warning level indicates potential damage to property. If the situation is not avoided, it may lead to damage to property. 
Follow the instructions in this warning to avoid material damage. 
NOTE 
Descriptive text… 
A descriptive text contains additional information that is important 
for further processing or for simplifying the procedure step explained. 

8  DRELLOSCOP 1020 
1.4  Limitation of liability 
The manufacturer assumes no liability for damage and operational 
faults resulting from: 
■ failure to observe these operating instructions, 
■ use for other than the intended purpose,  
■ deployment of non-trained or insufficiently-trained staff, 
■ use of non-approved equipment, 
■ faulty connection, 
■ previous work that is not part of the scope of supply, 
■ failure to use original replacement and acce ssory parts, 
■ technical modifications and changes not approv ed by DRELLO, 
■ failure to perform prescribed maintenance work. 
With the exception of further claims, DRELLO is liable for any errors or omissions within the framework of the warranty obligations 
stated in the contract. 
Claims for damage are excluded irrespective of the legal basis. 
1.5  Spare parts 
WARNING 
Danger of injury due to wrong or faulty spare 
parts! 
Incorrect or faulty replacement parts can lead to  
damage, malfunction or total breakdown of the 
equipment as well endangering the safety. 
► Use only the original spare parts of 
the manufacturer. 

DRELLOSCOP 1020  9 
2  Safety 
2.1  General 
This section provides important instructions on all safety aspects 
for optimum protection of staff as well as safe and smooth operation. 
WARNING 
Danger from failure to observe the safety instructions! 
Failure to observe the safety and handling instructions listed in these operating instructions can lead 
to considerable danger. 
► Always pay attention to all warnings and instruc-
tions specified here. 
2.2  Responsibility of the operator 
Since this device is used in the commercial sector, the operator is 
subject to the legal requirements for occupational safety. 
In addition to the occupational safety instructions in these operating 
instructions, the current safety, accident prevention and environmental protection regulations relevant for operation of the device 
must be complied with. 
The operator must 
■ be informed on the current industrial safety r egulation s and c on-
duct risk assessment to determine additional hazards specific to 
the device that result from the special work conditions at its lo c ation. These must be implemented in the for m of in structions for 
the operation of the device. 
■ continually check during the entire per iod of serv ice that all oper-
ating instructions created by hi m comply with current regulations 
and to modify them if necessary. 
■ clearly regulate and determine the responsi bilitie s of t he staff f or 
installation, operation, maintenance and c leaning 

10  DRELLOSCOP 1020 
■ ensure that all persons handling the dev ice have r ead and un der-
stood these operating instructions. In addit ion, he mu st ensure 
that persons are regularly trained and informed on all haz ar ds  
when using the device. 
■ check that staff observes the oper ating instru ctions a nd is aware 
of safety and danger while w orking w ith the dev ice. 
■ ensure that these operating instructions and all additional regula-
tions can be accessed by operating and ma intenanc e staff. 
■ determine a person responsible for the dev ice and allow him to 
reject instructions from third par ties that ar e prejud icial to safety! 
■ make the necessary protective equipment av ailab le to staff. 
The operator is also responsible that the device is always in perfect 
condition and the following therefore applies: 
■ The operator must ensure that the cleaning and mai ntenanc e in-
tervals stated in these operating instructions are adhered to. 

DRELLOSCOP 1020  11 
2.3  Staff requirements 
2.3.1  Staff qualifications 
WARNING 
Risk of injury due to insufficient qualification! 
Improper use can result in considerabl e damag e to 
persons or property. 
► All activities shall only be performed by qualified 
staff. 
The following qualifications are stated in these operating instructions for various different fields of activities. 
■ Instructed person 
was instructed by the operator on their assigned responsibilities 
and the possible dangers resulting from improper behaviour. 
■ Specialist staff 
is able to carry out assigned work tasks as well as recognise 
and prevent possible dangers based on his/her technical training, knowledge and experience, including knowledge of applicable regulations. 
Only those staff members are permitted who can be expected to reliably perform their task. Those staff members whose responsiveness is affected by substances such as medication shall not be 
permitted. 
Allow staff to be trained or instructed and/or persons undergoing 
general training to work on the device only under the constant supervision of an experienced person! 
NOTE 
Observe age and occupational-specific reg ulations 
at the location of the device when selecting staff. 

12  DRELLOSCOP 1020 
2.3.2  Unauthorised persons 
WARNING 
Danger for and resulting from unauthorised 
persons! 
Unauthorised persons who do not fulfil the requirements are not familiar with the dangers at the work 
location. 
► Do not permit unauthorised persons to be in the 
vicinity of the work area. 
► In case of doubt, approach the persons and 
instruct them to leave the work area. 
► Do not continue with work while the unauthor-
ised person is in the vicinity of the work area. 
2.3.3  Instruction 
Staff must be regularly instructed by the operator. 
NOTE 
In order to keep track and protocol all instruction 
sessions, participating members of staff are required to acknowledge with their signature. 

DRELLOSCOP 1020  13 
2.4  Intended use 
The device is portable and intended for visual che ck ing of mo v ing 
work sequences. It is possible to connect an external controller via 
machine impulse for example. 
Any use other than previously stated is considered as improper 
use. 
WARNING 
Danger from use for other than the intended 
purpose! 
Any use other than and/or going beyond the intended use of the device can lead to dangerous situations. 
► Only use the device for its intended purpose.  
► Pay attention to all specifications in these 
operating instructio ns. 
No claims of any kind will be accepted for damage resulting from 
use of the appliance for other than its intended purpose. The risk 
must be borne solely by the user. 
2.5  Device protection 
The DRELLOSCOP 1020 is protected during battery operation by 
an internal self-restoring fuse, which is not replaceable. If the 
DRELLOSCOP 1020 is operated via the NG-1020 mains supply, 
the device is protected by the fuse of the mains supply. 

14  DRELLOSCOP 1020 
2.6  Particular hazards 
2.6.1  Danger from stroboscopic light flashes 
WARNING 
Danger from stroboscopic light flashes 
In rare cases, stroboscopes can cause epileptic fits 
when operated at a frequency of approx. 10 – 20 Hz. 
The risk increases if the contrast between the flash 
and the ambient lighting is high. Even persons who 
have never experienced an epilept ic fit can be affected. Consequent injury such as falling over can 
therefore not be ruled out. 
► If possible, always work in normal ambient light 
conditions. 
► When setting the flash sequence, begin with the 
highest frequency. 
► Make sure that persons suffering from epilepsy 
are not in the vicinity of the device during operation. 
WARNING 
Danger from optical illusions! 
A rotating machine part appears to be stationary at 
certain settings of the device. Persons who are not 
informed of this effect may reach into or be caught 
by the running machine, which could lead to serious 
or even fatal injuries. 
► Inform all persons who stand in the vicinity of 
the illuminated area on the functionality of the 
device and make them aware of the danger that 
can result from the optical illusion. 

DRELLOSCOP 1020  15 
3  Technical specifications 
Dimensions   
Length / width  200 - 85 mm 
Height / with rotary adjuster  40 - 55 mm 
Weight  approx. 0.5 kg 
Controller 
Manual controller (internal)  via rotary adjuster, 
120...25000 min-1 or 
2...416.6 sec-1 
fast finder function by multiplica-
tion/division of the set flash sequence 
External controller  via rectangular pulse 10...24 V 
60…199999 min
-1 
 or 1…3333 sec-1 
display up to 99999 min-1 (1666.6 Hz) 
or 3333.3 sec-1 
smooth real-
time image shifting 0...360° 
and slow-motion function, automatic input 
frequency division from 416.66 sec-1 
Flash length control  automatic, depending on the 
flash sequence or manual by rotary 
adjuster, setting range 1...250 μs  
Maximum flash sequence  416.66 sec-1 or 25000 min-1 
Measured value display  5-digit 7-segment display, 
number height 7.6 mm 
Electrics 
Mains supply  3 x 1.2 V NiMH rechargeable batteries 
(AA), 
fast charging capability 
Plug-in mains supply 5 VDC 
Power consumption  400 mA @ 5 VDC 
Reverse polarity protection  yes 
Operating time (battery)  approx. 4 hours at full load 
(depending on battery type, 2850 mAh) 
Operating time (plug-in mains 
supply) 
Continuous operation 

16  DRELLOSCOP 1020 
Ambient conditions 
Ambient temperature range  0 … +4 5 °C 
Storage temperature range  -20 … +60 °C 
Degree of protection  IP50 
Illumination 
LED  High-performance LED, white radiating 
combined with highly-efficient optics  
Colour temperature  6500 K 
Illumination Ø  150 mm @ 300 mm object gap 
Illumination strength  3500 lx @ 200mm object gap; meas-
ured at 50 Hz and 50 µs flash length 
CE declaration of conformity  printed version on request 
NOTE 
Battery operation 
Following detection of undervoltage during battery 
operation (display flashes), the device can be  
operated for approx. 15 minutes. 

DRELLOSCOP 1020  17 
4  Description 
4.1  Description of functions 
The DRELLOSCOP 1020 is a portable LED hand-held stroboscope 
for use in a harsh industrial environment. 
Switching the appliance ON/OFF 
The device is switched on or off by pressing the ON/OFF button.  
A display test is performed after switching on. All display elements 
light up for approx. 4-5 seconds and subsequently switch to the 
basic setting (LED sec
-1
 lights up, display value is 50,000). P ress-
ing the "ON/OFF" button again, switches off the device. 
Internal controller (hereinafter referred to as manual controller) 
Flash sequence 2.00 sec-1 ...416.67 sec-1 / 120 min-1....25000 min-1. 
Setting takes place via the rotary adjuster. 
Turn clockwise  →  flash sequence increases 
Turn anticlockwise  →  flash sequence decreases 
Fast finder function 
Pressing the "Double" button mult ipl ies the curr ent flas h seq uenc e 
by a factor of 2. Pressing the "Halving" button divides the current 
flash sequence by two. Exceeding the lower or higher flash sequence limit (2Hz / 416.67Hz) is not possible and in this case, multiplication or division by 2 is not performed. This function allows 
convenient detection of the true flash sequence with respect to the 
object motion sequence. 
Explanation 
If an intermittent moving object seems to be standing still, the flash 
sequence corresponds to the motion sequence or the ratio is an integer number. However, the highest flash sequence possible 
should be set in order to produce a simple stati onary image . When 
this has been achieved, the flash sequence is multiplied by a factor 
of 2 by pressing the "Double" button. If a doubled stationary image 
is then produced, the previously set flash sequence is correct. If 
however, a single stationary image is produced, the set flash sequence was too low. Repeated doubling of the flash sequence 
helps to determine the correct motion sequence. If this is higher 
than the flash sequence range of the stroboscope allows, the true 
motion sequence can be determined using a following method: 

18  DRELLOSCOP 1020 
Starting with the highest flash sequence, the first two values are 
determined by reducing them, which then produces simple stationary images of the object. This then results in the true motion sequence 
True motion sequence f
x
 [Hz] = n ∙ f1 [Hz] 
with 
[ ]
[ ] [ ]
HzfHzf
Hzf
n
21
2
−
=
Example: 
Beginning with the highest flash sequence (416.66Hz), the flash 
sequence is reduced until a simple stationary image results. The 
flash sequence is named f
1
. 
The flash sequence is then reduced further until another simple stationary image can be seen. The motion sequence is named f
2
. 
To determine the "n" factor, the determined values f
1
 and f2 are in-
serted into the corresponding formula. The true motion sequence f
x
cannot be determined using the formula (fx = n ∙ f1). If rotating objects are being examined, rotation-symmetric al str u ct ur e s su ch as 
spoke wheels must be marked to rule out ambiguity due to symmetry. 
External controller 
Pressing the "External" button ( cogw heel sy mbo l) other w ise name d 
Extended External Control activates the "external co ntr ol " fun ctio n. 
The frequency of the impulse sequence supplied then appears in 
the display. The flash sequence is synchronised to the incoming  
control impulses and therefore creates the impression that the object is stationary even with heavily fluctuating movement for example. If no control signal is supplied to the "external input", the value 
0.0 appears in the display after approx. 2 seconds. 
If the input frequency is greater than 416.67 sec
-1
, the flash sequence is automatically split to a permissible flash sequence value. 
The displayed value corresponds to the original input frequency. 
Note that a frequency input greater than 1.6666 KHz (99999 min
-1
) 
cannot be displayed in min-1. Input frequencies greater than 
3.33 kHz are not permit ted, t h e error cod e (Err 1) is displayed. 
Flash sequences that are smaller than 1 Hz are not permissible 
and are indicated by an error code (Err 2). However, flash triggering still takes place irrespective of this error message. 

DRELLOSCOP 1020  19 
Menu control 
Additional function expansions or display values can be set via the 
menu control. 
Menu functions for manual control: 
■ Display value in sec
-1
■ Display value in min
-1
■ Flash duration display or setting 
Also with extended control 
■ Setting of the image position and display of the pha se angle i n 
degrees 
■ Setting of the slow-motion funct ion und disp lay of the slow-motion 
angle in degrees 
For further information, refer to the "Menu structure" section 
NOTE 
The menu level "Display value selection or functions" is closed after pressing the "Menu" button 
directly afterwards. The original setting remains 
unchanged. For all other levels, the selected menu 
functions are accepted. 
Generally, all settings in the menu can be confir me d 
by pressing the rotary adjuster. 
Sleep function 
If no settings to the device are made by the user, it is switched to 
sleep mode after approx. 16 minutes. This reduces the intensity of 
the display field and the keyboard considerably and the flash function is switched off. Pressing a button or the rotary adjuster switches the device back to the operating mode and the flash function on. 

20  DRELLOSCOP 1020 
4.2  Device overview 
1  Display  Displays the current value of the 
selected function. 
2  Display for min
-1 
  Display of flashes per minute. The LED 
lights up when the function is selected. 
3  "Menu" button  Menu control selection. The LED lights 
up when the function is selected. 

DRELLOSCOP 1020  21 
4  Rotary adjuster  The rotary adjuster is used to switch the 
flash mode on and off and for confirming 
the menu functions. 
Turning clockwise or anticlockwise, settings are made for the flash sequence 
during manual control, image position, 
slow-motion angle, flash duration, menu 
selection and the "sec
-1
" or "min-1" dis-
play. 
5  Double button  The current flash sequen ce is multipl ied 
by a factor of 2. This is for fast retrieval 
of the true object frequency. 
6  ON/OFF button  Switches the device ON/OFF. 
7  9-pole device 
plug 
Connection for the NG-1020 mains 
adapter and supply of the control signals 
for the "external control" mode 
8  Halving button  The current flash sequence is divided by 
a factor of 2. This is for fast retrieval of 
the true object frequency if the stationary 
image is displayed repeatedly. 
9  External button  Selection of external control. The LED 
lights up when the function is selected. 
10  Display for sec-1  Displays number of flashes per second. 
The LED lights up when the function is 
selected. 

22  DRELLOSCOP 1020 
4.2.1  Front view 
1  LED with lens  High-performance LED with integrated 
lens. 
4.2.2  View from underneath 
1  Lid fixing  Thread for removing the fixing screws of 
the battery compartment lid. 
2  Battery compart-
ment 
Battery compartment for accommodating 
3 rechargeable 1.2V AA /HR6-size batteries (see scope of delivery) 

DRELLOSCOP 1020  23 
4.3  Menu structure 
Menu button
M
Display secˉ1
Display min
ˉ1
Function dur.
POSITION
SL-MOTION
Display dur
Autom. dur. A
Manuel dur. F
Manuel dur. F
Press once for 
selection
Press twice for
break-off
External 
function
Yes
No
Selection via adjustor
Confirm entry by pressing 
the button and chose  
function
Rotary adjustor
Setting 
position
Setting 
slow motion

24  DRELLOSCOP 1020 
4.4  Type plate 
The type plate is located on the underneath of the device. It includes 
the following information: 
■ Device designation 
■ Serial number 
■ Connection values 
■ Options 

Transport, assembly and connection 
DRELLOSCOP 1020  25 
5  Transport, assembly and connection 
5.1  Scope of supply 
The DRELLOSCOP 1020 system is supplied with the following 
components depending on the system number: 
DRELLOSCOP 1020  system number: 1.1020.00001 
No. 
Designation 
Article number 
1  DRELLOSCOP 1020 
1.1020.60001 
1  NG-1020 plug-in mains supply 
1.1020.20001 
3  NiMH 1.2V / 2100mAh HR6 (AA) recharge-
able battery 
23.02.022 
1  TK-1020-01 plastic transport case 
39.1020.001 
DRELLOSCOP 1020 operating manual, English 
1.1020.2B001e 
DRELLOSCOP 1020  system number: 1.1020.00002 
No. 
Designation 
Article number 
1  DRELLOSCOP 1020 
1.1020.60001 
1  LA 1020B charging device (Basic 4 plus) 
59.1020.20001 
6  NiMH 1.2V / 2100mAh HR6 (AA) recharge-
able battery 
23.02.022 
1  TK-1020-02 plastic transport case 
39.1020.002 
DRELLOSCOP 1020 operating manual, English 
1.1020.2B001e 
DRELLOSCOP 1020  system number: 1.1020.00003 
No. 
Designation 
Article number 
1  DRELLOSCOP 1020 
1.1020.60001 
1  LA 1020B charging device (Basic 4 plus) 
59.1020.20001 
3  NiMH 1.2V / 2100mAh HR6 (AA) recharge-
able battery 
23.02.022 
1  NG-1020 plug-in mains supply 
1.1020.20001 
1  TK-1020-02 plastic transport case 
39.1020.002 
DRELLOSCOP 1020 operating manual, English 
1.1020.2B001e 

Transport, assembly and connection 
26  DRELLOSCOP 1020 
DRELLOSCOP 1020  system number: 1.1020.00004 
No. 
Designation 
Article number 
1  DRELLOSCOP 1020 
1.1020.60001 
1  LA 1020US charging device (Ultra Fast) 
59.1020.20003 
6  NiMH 1.2V / 2850mAh HR6 (AA) recharge-
able battery 
23.02.022 
1  TK-1020-02 plastic transport case 
39.1020.002 
DRELLOSCOP 1020 operating manual, English 
1.1020.2B001e 
DRELLOSCOP 1020  system number: 1.1020.00005 
No. 
Designation 
Article number 
1  DRELLOSCOP 1020 
1.1020.60001 
1  LA 1020US charging device (Ultra Fast) 
59.1020.20003 
3  NiMH 1.2V / 2850mAh HR6 (AA) recharge-
able battery 
23.02.023 
1  NG-1020 plug-in mains supply 
1.1020.20001 
1  TK-1020-02 plastic transport case 
39.1020.002 
DRELLOSCOP 1020 operating manual, English 
1.1020.2B001e 
NOTE 
Check the entire delivery according to the delivery 
note for completeness. We also refer you to our sales 
and delivery conditions. 
Measures in the event of transport damage 
Report damage due to defective packaging or damage incurred 
during transit to the haulage contractor, insurer and factory immediately after delivery . 
Take steps to reduce existing damage and prevent any further 
damage. 

Transport, assembly and connection 
DRELLOSCOP 1020  27 
5.2  Available accessories 
The following accessories are av ailab le for the device: 
No. Designation  Article number 
1  Sensors for the external controller 
on request 
5.3  Unpacking 
Remove all packaging materials and protective foils from the product and the accessories before using it for the first time. 
NOTE 
► Do not remove the rating plate or any warning 
signs on the appliance. 
► If possible, keep the original packaging during the 
guarantee period in order to be able to pack the 
appliance properly in the event of a guarantee 
claim. Transport damage will invalidate the guarantee. 
NOTE 
The packaging materials used can be recy cled.  When 
no longer required, dispose of the packaging materials according to local environmental regulations. 

Transport, assembly and connection 
28  DRELLOSCOP 1020 
5.4  Storage 
The following regulations apply for storage: 
■ Store at a dry place. Maximum relativ e humidity : 80%, non-
condensing 
■ Protect from direct sunlight. Keep storage temp er ature 
between -20 … +60 °C. 
■ Store at a dust-free location. 
■ Avoid mechanical vibration and damages.  
NOTE 
After use, store the device in the transport case supplied and also in the original packaging if possible. 
 CAUTION 
Risk of damage to the device due to leaking batteries! 
When storing for longer periods of time, ´the rechargeable batteries can leak and damage the device. 
► Before storing for longer periods of time, remove 
the batteries and store them in the battery compartments proved in the transport case. 

Transport, assembly and connection 
DRELLOSCOP 1020  29 
5.5  Requirements for the place of use 
■ At the place of use, the device may not be subject to extreme 
temperatures or humidity. Comply w ith the specificat ions for ambient conditions specified in the t echnical data. 
■ Avoid setting up at locations with direct sunl ight .  
■ Avoid strong ambient lighting at the place of u se in order to 
achieve a good contrast. 
■ Do not subject the device to vibration or knoc ks. 
5.6  Mains operation 
When using the NG-1020 plug-in mains supply (depending on the 
scope of supply), battery operation is switched off automatically. 
Carry out the electrical connection of the device as follows: 
 
Insert the 9-pole cable socket of the connectin g cabl e  
for the NG-1020 plug-in mains supply into the 9-pole device 
connection plug of the DRELLOSCOP 1020 and secure it 
against loosening by means of the locking screws. 
 
Insert the plug of the NG-1020 plug-in mains supply into the 
mains socket. 
 CAUTION 
Risk of damage to the device due to incorrect pin 
assignment! 
Incorrect pin assignment of the connecting cable can 
lead to destruction of the electrical components in 
the device. 
► Only use the NG-1020 plug-in mains supply from 
the manufacturer. 

Transport, assembly and connection 
30  DRELLOSCOP 1020 
5.7  Connecting an external controller 
If the device is to be connected to an external controller, the connections on the 9-pole plug must be undertaken by a qualified specialist electrician. 
Pin assignment 
The pin assignment of the connecting plug is depicted as follows: 
Numbering of the device connection plug (top 
view) 
Pin  Signal  Direction  Level 
1  not assigned     
2  not assigned     
3  Supply voltage (+)  Input  5 VDC 
4  not assigned     
5  Trigger impulse (0 V)  Input  0 V trigger 
6 
Trigger impulse
 (+)___----___    10...24 VS 
7  not assigned     
8  Supply voltage (-)  Input  0 V 
9  Supply voltage (-)  Input  0 V 

DRELLOSCOP 1020  31 
6  Operation 
6.1  Switching the device ON/OFF 
The device is switched on or off by pressing the ON/OFF button. 
After switching on, a display test is performed. All display elements 
light up for approx. 4-5 seconds and subsequently switch to the 
basic setting (LED sec
-1
 lights up, display value 50,000). The de-
vice is subsequently ready for operation. 
The device is switched off by pressing the butto n again . 
6.2  Operating 
6.2.1  Selecting the operating mode 
The device can be operated in two modes: 
Manual controller 
This function is active when the LED of the "EXTERN" button is not 
lit up. If the LED of the "EXTERN" button lights up, press the "EXTERN" button to activate manual control. 
In manual control, the flash sequence is set with the rotary adjuster. 
 
The object to be controlled should speed up to its target speed 
in order to adjust the flash sequence. 
 
Press the rotary adjuster to switch on the flash trigger. 
 
Set the flash sequence via the rotary adjuster so that a stationary image is seen by the observer.  
The flash sequence speed is increased by turning the rotary adjuster clockwise and decreased by turning anticlockwise. 
 
If multiple images the object are seen, press the "Halving" button. Repeat this procedure until a single stationary image of the 
object is achieved. 

32  DRELLOSCOP 1020 
External controller 
This function is available when the device is connected to a pulse 
generator, from which it obtains control impulses. This type of flash 
sequence control also generates the desired stationary image even 
if the machine speed changes. 
 
Press the "EXTERNAL" button . T he ex ternal control ler is act ivated when the LED of the button lights up. 
The frequency of the supplied pulse sequence appears in the 
display. If no control signal is suppl ied to the "ex ternal inp ut ",  
the value 0.0 appears in the display after approx. 2 seconds. 
NOTE 
► If the input frequency is greater than 416.67 sec-1, 
the flash sequence is split down to a permissi ble 
flash sequence value automatically. The value 
displayed corresponds to the original input frequency. 
► An input frequency greater than 1.666 KHz can-
not be displayed in min
-1
. 
► Input frequencies greater than 3.333 kHz are not 
permissible and are indicated by an error code  
"Err 1". 
► Flash sequences that are smaller than 1 Hz are 
not permissible and are indicated by an error 
code "Err 2". However, flash triggering still takes 
place irrespective of this error message. 
NOTE 
If the menu button is pressed, the measured value 
can be depicted also for input signals smaller than 
1Hz or greater than 3.333Khz in sec
-1
 or up to 
1.666KHz in min
-1
 respectively.  

DRELLOSCOP 1020  33 
6.3  Further setting options for flash operation  
(manual control) 
6.3.1  Setting the flash sequence display 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until the lights up with "Display min-1" or 
"Display sec
-1
". 
 
If the desired display (min-1 or sec-1) was selected, press the rotary adjuster to confirm selection. 
NOTE 
The menu is closed automatically and all settings are 
stored. 
6.3.2  Displaying the current flash duration 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until the "dur." function is displayed. 
 
Press the rotary indicator. 
 
The current flash duration is displayed in [μs]. Either "dA" for  
Duration-Automatic-Mode or "dF" for Duration-Fix-Mode is in 
front of the number. 
 
If the setting is to be changed, select the corresponding function 
(refer to following section). 
 
Press the rotary adjuster to either set the flash duration  
(Fix-Mode) or to exit the function. The changed setting is saved. 
NOTE 
To exit the function, press the Menu button again. 
The menu is closed. 

34  DRELLOSCOP 1020 
6.3.3  Setting the "Duration-Auto-Modus" variable flash duration 
The flash duration is adjusted automatically to the flash sequence 
with this function. Automatic adjustment gives the impression of a 
constant brightness irrespective of the flash sequence. 
NOTE 
Use this function if a continual impression of brightness is desired irrespective of the flash sequence 
used. 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until "dur." is displayed. 
 
Press the rotary indicator. 
 
The current flash duration is displayed in [μs]. Either "dA" for 
Duration-Automatic-Mode or "dF" for Duration-Fix-Mode is in 
front of the number. 
 
Turn the rotary adjuster until "dA" is displayed. 
 
Press the rotary indicator. The device is in automatic mode and 
the current flash duration is displayed in [μs]. 
 
Press the "Menu" or rotary adjuster button. The menu control is 
closed and the settings saved. 

DRELLOSCOP 1020  35 
6.3.4  Setting the flash duration "Duration-Fix-Modus" 
This function allows the flash duration to be set to a fixed value irrespective of the flash sequence. Adjustment of the fla sh sequen ce 
makes it possible to eliminate possible motion blur while depicting 
the moving object. 
NOTE 
Use this function if significant motion blur is detected 
or the brightness needs to be reduced. 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until "dur." is displayed. 
 
Press the rotary indicator. 
 
The current flash duration is displayed in [μs]. Either "dA" for 
Duration-Automatic-Mode or "dF" for Duration-Fix-Mode is in 
front of the number. 
 
Turn the rotary adjuster until "dur F" is displayed. 
 
Press the rotary indicator. The device is in fix mode. 
 
Set the flash duration by turning the rotary adjuster. 
 
Press the "Menu" or rotary adjuster button. The menu control is 
closed and the settings saved. 
NOTE 
Manual setting of the flash duration may not exceed 
the maximum permissible flash duration for the respective flash sequence. 
An additional protective function (overload protection) 
reduces the manually set flash duration automatically 
when this reaches a non-permissible value as a result of a change in the flash sequence. 

36  DRELLOSCOP 1020 
6.4  Further setting options for flash operation  
(external control) 
6.4.1  Image shift (PHASE) 
The object to be controlled can be "shifted" into the optimum  
position. The flash moment is changed electro nic al ly that another 
image position of the object can be viewed. 
NOTE 
This function is useful when the object does not need 
to be completely illuminated. 
NOTE 
The "image shift" function is deactivated in the "external controller" mode after switching on the device. 
The "PHASE" function must called first to enable it. 
Switching off the function is only possible if either the 
"slow-motion" functi on is selec ted or the dev ice is 
briefly switched off and on again. 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until "PHASE" is displayed. 
 
Press the rotary adjuster to activate the image shift setting and 
to read the current "phase angle" (image position) with respect 
to the input signal. 
 
Turn the rotary adjuster to set the desired image position. 
 
Press the "Menu" or rotary adjuster button. The menu control is 
closed and the settings saved. 
NOTE 
After closing the "PHASE" menu functi on, the set 
image position remains and can be further modified 
with the rotary adjuster. However, the phase angle is 
no longer displayed. 

DRELLOSCOP 1020  37 
6.4.2  Setting the slow-motion function 
With external control of the flash sequence a continual, apparent 
image shift can be set. The eye perceives this as a sequence in 
slow motion. 
NOTE 
The "scrolling" is deactivated after switching on the 
device in "external control" operating mode. The 
"SLO" function must be called first to enable it. 
Switching the function on/off is only possible when 
either the "PHASE" function (image shift) is selected 
or the device is switched off briefly and then switched 
on again. 
 
Press the "Menu" button. The LED lights up when the function 
is selected. 
 
Turn the rotary adjuster until "SLO" is displayed. 
 
Press the rotary adjuster to activate the slow-motion function 
and to read the current "slow-motion angle" with respect to the 
input signal. 
 
Set the slow-motion speed by turning the rotary adjuster 
 
Press the "Menu" or rotary adjuster button. The menu control is 
closed and the settings saved. 
NOTE 
The apparent slow-motion effect (scrolling) remains 
after switching off this function and can be further 
modified with the rotary adjuster. However, the "slowmotion angle" is no longer displayed. 
NOTE 
The "slow-motion angle" serv es as a setting aid. 
Once set, it is adjusts itself automatically to the 
changing object speed. This automatic adjustment 
keeps the apparent circulation speed constant irrespective of the object speed. 

38  DRELLOSCOP 1020 
7  M aint en an ce and rep air 
7.1  Maintenance 
No maintenance work on the device is necessary. Only the rechargeable batteries used must be charged as required with the 
charging station supplied.  
NOTE 
If the DRELLOSCOP 1020 is not to be used for a 
longer period of time, remove the batteries from the 
device and insert them into the battery compartment 
provided in the transport case. 
7.2  Changing the batteries 
 
Switch off the device. 
 
Unscrew both screws of the battery lid and remove it. 
 
Remove any batteries. 
 
Insert the loaded batteries according to polarity into the battery  
compartment, replace the lid and the screws. 
 
Charging the batteries 
NOTE 
When the battery voltage is too low, the indicator in 
the display starts flashing. If the voltage sinks further, 
flash operation switches off automatically and "dc Lo" 
appears in the display. The batteries must be replaced. 
The device switches off automatic ally w ithin 30 seconds. 
NOTE 
If the DRELLOSCOP 1020 is not to be used for a 
longer period of time, remove the batteries from the 
device and insert them into the battery compartment 
provided in the transport case. 

DRELLOSCOP 1020  39 
7.3  Cleaning 
Clean the lens (light emitting surface) with a damp cloth as required. 
If dirty, clean the housing of the device with a slightly damp, lintfree cloth. Do not use cleaners containing solvents. 
7.4  Troubleshooting 
Fault  Cause  Remedy 
No display  Batteries discharged.  Recharge batteries 
No voltage supply.  Check 
connecting cable. 
Stroboscope not  
switched on. 
Switch on  
stroboscope. 
Display is flashing 
Battery voltage in 
lower permitted range. 
Change the batteries 
immediately. 
Display is flashing, "dc Lo" is 
displayed and 
operation not 
possible. 
Battery voltage too 
low. 
Replace batteries  
immediately. 
The device does 
not flash with 
manual controller. 
"External controller" 
operating mode is activated without a trigger impulse. 
Switch over to "manual controller" operating mode. 
The device does 
not flash with external controller. 
There is no trigger 
impulse. 
Check external impulse generator 
"Err 1" display  Input frequency above 
3.33 kHz. 
Reduce input frequency. 
"Err 2" display  Input frequency below 
1.00 Hz. 
Increase input frequency. 

40  DRELLOSCOP 1020 
7.5  Repairs 
Do not perform repairs on the device yourself. Contact customer 
service at DRELLO. Improper work can result in personal injuries, 
damage to property or damage to the device itself. 
If repairs must be performed, please cont act: 
DRELLO Ing. Paul Drewell GmbH & Co. KG 
Customer service 
Andreas-Bornes-Strasse 46 
D-41179 Mönchengladbach 
Telephone:  +49 - (0)2161 - 909 - 6 
Telefax:  +49 - (0)2161 - 909 - 700 
Email:   service@drello.de 
Internet:  www.drello.de 
7.6  Disposal 
This product may not be disposed of in the domestic refuse within 
the European Union. 
Dispose of the device in accordance with the EC Directive Waste 
Electrical and Electronic Equipment 2002/96/EC. Questions on disposal can be answered by the responsible local authority.