Polytec OFV-3001 User manual

Title
User Manual
Laser Doppler Vibrometer
Controller OFV-3001
Sensor Heads OFV-303/-353
OFV-511/-512
Advanced Test Equipment Rentals
www.atecorp.com 800-404-ATEC (2832)
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Warranty and Service
The warranty for this equipment complies with the regulations in our general terms and
conditions in their respective valid version.
This is conditional on the equipment being used as it is intended and as described in this
manual.
The warranty does not apply to damage caused by incorrect usage, external mechanical
influences or by not keeping to the operating conditions. The warranty also is invalidated in the
case of the equipment being tampered with or modified without authorization.
To return the equipment always use the original packaging. Otherwise we reserve the right to
check the equipment for transport damage. Please mark the package as fragile and sensitive to
frost. Include an explanation of the reason for returning it as well as an exact description of the
fault. You can find advice on fault diagnosis in chapter 6.
Trademarks
Brand and product names mentioned in this manual could be trademarks or registered
trademarks of their respective companies or organizations.
Identification Labels
Controller Sensor Head

i
Contents
Contents
1 Safety Information 1-1
1.1 Laser Safety ....................................................................................................................... 1-1
1.2 Laser Warning Labels......................................................................................................... 1-2
1.2.1 EC Countries ............................................................................................................ 1-2
1.3 Laser Warning Labels......................................................................................................... 1-4
1.3.1 Non-EC Countries..................................................................................................... 1-4
1.4 Electrical Safety.................................................................................................................. 1-6
2 Introduction 2-1
2.1 System Overview................................................................................................................ 2-1
2.2 Component Summary ......................................................................................................... 2-2
3 First Steps 3-1
3.1 Operating and Maintenance Requirements ......................................................................... 3-1
3.2 Unpacking and Inspection...................................................................................................3-2
3.3 Control Elements of the Vibrometer ....................................................................................3-3
3.3.1 Controller.................................................................................................................. 3-3
3.3.2 Sensor Head OFV-303.............................................................................................. 3-7
3.3.3 Sensor Head OFV-353.............................................................................................. 3-8
3.3.4 Sensor Head OFV-511.............................................................................................. 3-9
3.3.5 Sensor Head OFV-512.............................................................................................3-11
3.4 Installation and Functional Test......................................................................................... 3-13
3.4.1 Vibrometer with Sensor Head OFV-303/-353........................................................... 3-13
3.4.2 Vibrometer with Sensor Head OFV-511/-512........................................................... 3-14
4 Making Measurements 4-1
4.1 Start-up............................................................................................................................... 4-1
4.1.1 Vibrometer with Sensor Head OFV-303/-353............................................................. 4-1
4.1.2 Vibrometer with Sensor Head OFV-511/-512............................................................. 4-2
4.1.3 Displaying the Output Signals ................................................................................... 4-3
4.2 Selecting Suitable Settings ................................................................................................. 4-4
4.2.1 Velocity or Displacement Measurement? .................................................................. 4-4
4.2.2 Settings for Velocity Measurement............................................................................4-5
4.2.3 Settings for Displacement Measurement (optional) ................................................. 4-10
4.2.4 Optimal Stand-Off Distances for the Sensor Heads ................................................. 4-14

ii
Contents
5 Operating the Vibrometer 5-1
5.1 Switching On and Off...........................................................................................................5-1
5.2 Beam Shutter and Emission Indicator..................................................................................5-1
5.3 Signal Level Display ............................................................................................................5-2
5.4 Focusing the Laser Beam....................................................................................................5-2
5.5 Exchanging the Front Lens..................................................................................................5-4
5.6 Making Single Point Measurements with the Sensor Head OFV-512 ...................................5-5
5.7 Fixing the Focus (only OFV-353) .........................................................................................5-5
5.8 Transport Safety Mechanism (only OFV-511/-512)...............................................................5-6
5.9 Operating the Vibrometer via the Display of the Controller...................................................5-7
5.9.1 Operating Philosophy.................................................................................................5-7
5.9.2 Organization of the Menus.........................................................................................5-8
5.9.3 The Individual Menus.................................................................................................5-9
5.10 Setting Measurement Ranges and Filters ........................................................................5-11
5.11 Displaying the Configuration of the Controller ..................................................................5-11
5.12 Configuring the Interfaces................................................................................................5-11
6 Fault Diagnosis 6-1
6.1 General Tests ......................................................................................................................6-1
6.2 No Laser Beam....................................................................................................................6-2
6.3 No Measurement Signal ......................................................................................................6-3
6.4 Checklist for Fault Diagnosis ...............................................................................................6-5
6.4.1 Controller OFV-3001 with the Sensor Head OFV-303/-353 ........................................6-5
6.4.2 Controller OFV-3001 with the Sensor Head OFV-511/-512.........................................6-6
7 Technical Specifications 7-1
7.1 Controller OFV-3001............................................................................................................7-1
7.1.1 General Data .............................................................................................................7-1
7.1.2 Interfaces...................................................................................................................7-1
7.1.3 Low Pass Filter..........................................................................................................7-2
7.1.4 Signal Voltage Output VELOCITY OUTPUT...............................................................7-2
7.1.5 Signal Voltage Output DISPLACEMENT OUTPUT (optional) .....................................7-5
7.2 Sensor Head OFV-303/-353 ................................................................................................7-6
7.2.1 General Data .............................................................................................................7-6
7.2.2 Optics........................................................................................................................7-6
7.3 Sensor Head OFV-511/-512.................................................................................................7-8
7.3.1 General Data .............................................................................................................7-8
7.3.2 Optics........................................................................................................................7-8
Appendix A: Optional Accessories for the Sensor Head OFV-303/-353
Appendix B: Optional Accessories for the Sensor Head OFV-511/-512
Appendix C: Basics of the Measurement Procedure
Appendix D: Functional Description of the Controller
Appendix E: Interface Operation RS-232 and IEEE-488/GPIB

1-1
1 Safety Information
1 Safety Information
1.1 Laser Safety
The light source of the vibrometer is a helium neon laser. It is important to
understand that laser light has different properties than ordinary light sources.
Laser radiation is generally extremely intense due to the beam's low
divergence and great care should be taken when handling laser instruments
that the direct or reflected beam does not enter the eye. To ensure this, the
following precautions have been taken:
• In general, Polytec equipment complies with the standards EN 60825-1
(DIN VDE 0837) and CFR 1040.10 (US).
• The optical output of the laser is less than 1mW for the sensor heads
OFV-303/-353 and OFV-511 providing the equipment is used in the
manner for which it was intended. This means that the vibrometer
conforms with laser class 2 (II) and is generally very safe. Even when
optimally focused, the laser radiation is not intense enough to harm the
skin.
• The optical output of the laser is less than 5mW ( < 1mW per fibre) for the
sensor head OFV-512 providing the equipment is used in the manner for
which it was intended. This means that the vibrometer conforms with
laser class 3R (IIIa) and is generally very safe. Even when optimally
focused, the laser radiation is not intense enough to harm the skin.
• The sensor head has been equipped with a beam shutter which can be
used to block the laser beam during the warm-up phase or when the
vibrometer is not in use, although switched on.
• The emission indicator on the sensor head indicates the activity of the
laser and thus potential harm caused by emitted laser beams.
• The beam shutter is always less then 2m away from the aperture of the
laser beam. Special editions of the fiber optical sensor heads with fiber
lengths of 3m are fitted with an additional emission indicator which is
integrated in the fibers.
• The laser is switched on via a key switch on the controller. The key can
only be removed when the controller is switched off.
• It is not necessary to open the housing of the sensor head when using
the vibrometer as intended. Opening the housing will invalidate the
warranty.
Please pay attention to the following safety precautions when using the
vibrometer:
• Never look directly into the laser beam with the naked eye or with the aid
of mirrors or optical instruments!
• Only switch the beam shutter to the ON position when you are making
measurements!
• To position the sensor head, switch the beam shutter to the OFF position.
Only when the sensor head is roughly in place and has been fixed in a
stable position, switch the beam shutter to ON.
• Do not use any reflective tools, watches etc. when you are working in the
path of the laser beam!

1-2
1 Safety Information
1.2 Laser Warning Labels
1.2.1 EC Countries
Warning
labels
The laser warning labels for the sensor heads in EC countries are shown in
figure 1.1. Label 2 , 3 and 4 are affixed or enclosed in the language of the
customer’s country. Their position on the sensor head OFV-303/-353 is shown
in figure 1.2 and on the sensor head OFV-511 resp. OFV-512 in figure 1.3.
Laser class 2 for
OFV-303/-353 and OFV-511 Laser class 3R for OFV-512
Figure 1.1: Laser warning labels for the vibrometer in EC countries
1
2
3
4

1-3
1 Safety Information
Position The position of the laser warning labels in EC countries on the sensor head
OFV-303/-353 is shown in figure 1.2.
The position of the laser warning labels in EC countries on the sensor head
OFV-511 resp. OFV-512 is shown in figure 1.3.
For the sensor head OFV-511, label 3 is affixed inside.
For the sensor head OFV-512, label 4 is affixed inside and label 3 is enclosed
with the sensor head as it is not possible to affix it on the mini sensor due to
its size. Please affix this label clearly visible near the mounted mini sensor or
fiber head.
Figure 1.2: Position of the laser warning labels on the sensor head OFV-303/-353 in EC
countries
1 2 4
B e a m
3
Figure 1.3: Position of the laser warning labels on the sensor head OFV-511/-512 in EC countries
S I G N A L
P R O C E S S O R
A C H T U N G !
B i t t e v o r d e m T r a n s p o r t
d i e T r a n s p o r t s i c h e r n g b e t ä t i g e n
C A U T I O N !
P l e a s e s e c r e t r a n s p o r t m e c h a n i s m
b e f o r e s h i p m e n t
M E A S U R E M E N T T R A N S P O R T
B e a m
1
2

1-4
1 Safety Information
1.3 Laser Warning Labels
1.3.1 Non-EC Countries
Warning labels The laser warning labels for the sensor heads in non-EC countries are shown
in figure 1.4. Their position on the sensor head OFV-303/-353 is shown in
figure 1.5 and on the sensor head OFV-511 resp. OFV-512 in figure 1.6.
Laser class II for
OFV-303/-353 and OFV-511
Laser class IIIa for
OFV-512
Figure 1.4: Laser warning labels for the vibrometer in non-EC countries

1-5
1 Safety Information
Position The position of the laser warning labels in non-EC countries on the sensor
head OFV-303/-353 is shown in figure 1.5.
The position of the laser warning labels in non-EC countries on the sensor
head OFV-511 resp. OFV-512 is shown in figure 1.6.
Label 4 is affixed inside. Label 3 is enclosed with the sensor head as it is not
possible to affix it on the mini sensor due to its size. Please affix this label
clearly visible near the mounted mini sensor or fiber head.
Figure 1.5: Position of the laser warning labels on the sensor head OFV-303/-353 in non-EC
countries
1 4 2
3
B e a m
Figure 1.6: Position of the laser warning labels on the sensor ead OFV-511/-512 in non-EC countries
S I G N A L
P R O C E S S O R
A C H T U N G !
B i t t e v o r d e m T r a n s p o r t
d i e T r a n s p o r t s i c h e r n g b e t ä t i g e n
C A U T I O N !
P l e a s e s e c r e t r a n s p o r t m e c h a n i s m
b e f o r e s h i p m e n t
M E A S U R E M E N T T R A N S P O R T
B e a m
1
2

1-6
1 Safety Information
1.4 Electrical Safety
The vibrometer complies with the electrical safety class I. Electrical shock
protection is achieved by a fully metallic housing connected to protective
ground. Please pay attention to the following safety precautions when using
the vibrometer:
• The vibrometer should only be connected via a three pin mains cable to
an AC mains supply 50/60Hz with a grounded protective conductor with a
nominal voltage which corresponds to the voltage set on the voltage
selector.
• Defective mains fuses may only be replaced by fuses of the same kind
with their rating given on the back of the controller.
• None of the equipment may be used with open housing. As a general rule,
before removing parts of the housing, the mains cable has to be
unplugged.
• Air inlets and outlets must always be kept uncovered to ensure effective
cooling. If the cooling fan stops working, the vibrometer is to be switched
off immediately.