WAGO 750-645 User manual

Fieldbus Independent
I/O Modules
2AI/2DO VIB VRMS/SPM Multi
750-645
Manual
Version 1.2.1

ii • General
WAGO-I/O-SYSTEM 750
I/O-Modules
Copyright 2008 by WAGO Kontakttechnik GmbH & Co. KG
All rights reserved.
WAGO Kontakttechnik GmbH & Co. KG
Hansastraße 27
D-32423 Minden
Phone: [phone] – 0
Fax: [phone] – 1 69
E-Mail: [email protected]
Web: http://www.wago.com
Technical Support
Phone: [phone] – 5 55
Fax: [phone] – 85 55
E-Mail: [email protected]
Every conceivable measure has been taken to ensure the correctness and com-
pleteness of this documentation. However, as errors can never be fully ex-
cluded, we would appreciate any information or ideas at any time.
E-Mail: [email protected]
We wish to point out that the software and hardware terms as well as the
trademarks of companies used and/or mentioned in the present manual are
generally trademark or patent protected.

Important Notes •3
WAGO-I/O-SYSTEM 750
I/O-Modules
Content
1Important Notes ..........................................................................................5
1.1 Legal Principles........................................................................................5
1.1.1 Copyright ............................................................................................. 5
1.1.2 Personnel Qualification .......................................................................5
1.1.3 Conforming Use of Series 750 ............................................................6
1.1.4 Technical Condition of the Devices ....................................................6
1.2 Standards and Regulations for Operating the 750 Series......................... 7
1.3 Symbols....................................................................................................8
1.4 Safety Information....................................................................................9
1.5 Font Conventions ................................................................................... 10
1.6 Number
Notation.................................................................................... 10
1.7 Scope ......................................................................................................10
2Condition Monitoring...............................................................................11
2.1 Tasks and Options ..................................................................................11
2.2 Machine Condition Monitoring with VIB-I/O Modules........................11
2.2.1 Fundamentals.....................................................................................11
2.2.1.1 Vibration Severity.........................................................................11
2.2.1.2 ISO 10816-3..................................................................................11
2.2.2 Roller Bearing Analysis.....................................................................13
2.2.3 Shock Impulses..................................................................................13
2.2.3.1 Measuring Shock Impulses...........................................................13
2.2.3.2 Shock Impulse Evaluation ............................................................ 14
2.2.3.3 The Shock Impulse Carpet Value ................................................. 14
2.2.3.4 The Shock Impulse Peak Value ....................................................15
2.2.4 Damage History................................................................................. 16
2.2.4.1 Three Stages to Evaluate a Roller Bearing State ..........................16
2.2.4.2 The Evaluation Scale .................................................................... 17
2.2.4.2.1 Good Operating Condition....................................................... 17
2.2.4.2.2 Limited Operating Condition ...................................................17
2.2.4.2.3 Poor Operating Condition ........................................................18
2.2.5 Typical Shock Impulse Diagrams...................................................... 19
2.2.5.1 Bearing in Good Condition........................................................... 19
2.2.5.2 Bearing Damage of Foreign Matter in the Lubricant ...................19
2.2.5.3 Installation Errors or Insufficient Lubrication..............................20
2.2.5.4 Dry-Run or Cavitation .................................................................. 20
2.2.6 The Measuring Point .........................................................................21
3Overview Condition Monitoring Components 750-645, 750-925 .........24
4I/O Modules...............................................................................................25
4.1 Special Modules .....................................................................................25
4.1.1 750-645 [2AI/2DO VIB VRMS/SPM Multi].................................... 25
4.1.1.1 View.............................................................................................. 25
4.1.1.2 Description.................................................................................... 25
4.1.1.3 Display Elements ..........................................................................28

4 •Important Notes
WAGO-I/O-SYSTEM 750
I/O-Modules
4.1.1.4 Schematic Wiring Diagram...........................................................29
4.1.1.5 Technical Data ..............................................................................30
4.1.1.6 Function Description.....................................................................32
4.1.1.6.1 Operating Mode........................................................................33
4.1.1.6.1.1 Measuring Process in Single-Channel Mode ......................33
4.1.1.6.1.2 Measuring Process in 2-Channel Mode ..............................33
4.1.1.6.2 Parameter Vibration Monitoring (RMS)..................................35
4.1.1.6.3 Parameter Roller Bearing Monitoring (SPM)..........................35
4.1.1.7 Process Image ...............................................................................36
4.1.1.7.1 Overview ..................................................................................36
4.1.1.7.2 Control and Status Byte in Process Data Communication.......37
4.1.1.8 Setting the 750-645 Module Using Register Communication......42
4.1.1.8.1 Control- and Status Byte at Register Communication .............44
4.1.1.9 Setting the 750-645 Module with WAGO-I/O-CHECK 2............46
5Accessories.................................................................................................49
5.1 Sensors....................................................................................................49
5.1.1 750-925 [Tandem-Piezo® Acceleration Sensor]................................49
5.1.1.1 View.............................................................................................. 49
5.1.1.2 Description....................................................................................49
5.1.1.3 Technical Data ..............................................................................50
5.1.1.4 Screwed Adapter with M8 Thread................................................52
5.1.1.5 Electrical Connection....................................................................54
5.1.1.6 Measurement Report Template.....................................................55
6Use in Hazardous Environments .............................................................57
6.1 Marking Configuration Examples..........................................................58
6.1.1 Marking for Europe according to CENELEC and IEC .....................58
6.1.2 Marking for America according to NEC 500 ....................................61
6.2 Installation Regulations.......................................................................... 62
6.2.1 Special Conditions for Safe Operation of the ATEX and IEC Ex (acc.
DEMKO 08 ATEX 142851X and IECEx PTB 07.0064).................. 63
6.2.2 Special conditions for safe use (ATEX Certificate TÜV 07 ATEX
554086 X) ..........................................................................................64
6.2.3 Special conditions for safe use (IEC-Ex Certificate TUN 09.0001 X)66
6.2.4 ANSI/ISA 12.12.01 ........................................................................... 68

Important Notes •5
Legal Principles
WAGO-I/O-SYSTEM 750
I/O-Modules
1 Important Notes
This section provides only a summary of the most important safety
requirements and notes which will be mentioned in the individual sections. To
protect your health and prevent damage to the devices, it is essential to read
and carefully follow the safety guidelines.
1.1 Legal Principles
1.1.1 Copyright
This manual including all figures and illustrations contained therein is subject
to copyright. Any use of this manual which infringes the copyright provisions
stipulated herein, is not permitted. Reproduction, translation and electronic
and phototechnical archiving and amendments require the written consent of
WAGO Kontakttechnik GmbH & Co. KG, Minden. Non-observance will
entail the right of claims for damages.
WAGO Kontakttechnik GmbH & Co. KG reserves the right of changes
serving technical progress.
All rights developing from the issue of a patent or the legal protection of
utility patents are reserved to WAGO Kontakttechnik GmbH & Co. KG.
Third-party products are always indicated without any notes concerning patent
rights. Thus, the existence of such rights must not be excluded.
1.1.2 Personnel Qualification
The use of the product described in this manual requires special qualifications,
as shown in the following table:
Activity Electrical specialist Instructed
personnel*)
Specialists**) having
qualifications in PLC
programming
Assembly X X
Commissioning X X
Programming X
Maintenance X X
Troubleshooting X
Disassembly X X
*) Instructed persons have been trained by qualified personnel or electrical specialists.
**) A specialist is someone who, through technical training, knowledge and experience,
demonstrates the ability to meet the relevant specifications and identify potential dangers in
the mentioned field of activity.

6 • Important Notes
Legal Principles
WAGO-I/O-SYSTEM 750
I/O-Modules
All personnel must be familiar with the applicable standards.
WAGO Kontakttechnik GmbH & Co. KG declines any liability resulting from
improper action and damage to WAGO products and third party products due
to non-observance of the information contained in this manual.
1.1.3 Conforming Use of Series 750
The couplers and controllers of the modular I/O System 750 receive digital
and analog signals from the I/O modules and sensors and transmit them to the
actuators or higher level control systems. Using the WAGO controllers, the
signals can also be (pre-)processed.
The device is designed for IP20 protection class. It is protected against finger
touch and solid impurities up to 12.5mm diameter, but not against water
penetration. Unless otherwise specified, the device must not be operated in
wet and dusty environments.
1.1.4 Technical Condition of the Devices
For each individual application, the components are supplied from the factory
with a dedicated hardware and software configuration. Changes in hardware,
software and firmware are only admitted within the framework of the
possibilities documented in the manuals. All changes to the hardware or
software and the non-conforming use of the components entail the exclusion
of liability on the part of WAGO Kontakttechnik GmbH & Co. KG.
Please direct any requirements pertaining to a modified and/or new hardware
or software configuration directly to WAGO Kontakttechnik GmbH & Co.
KG.

Important Notes •7
Standards and Regulations for Operating the 750 Series
WAGO-I/O-SYSTEM 750
I/O-Modules
1.2 Standards and Regulations for Operating the 750 Series
Please observe the standards and regulations that are relevant to your
installation:
The data and power lines must be connected and installed in compliance
with the standards to avoid failures on your installation and eliminate any
danger to personnel.
For installation, startup, maintenance and repair, please observe the
accident prevention regulations of your machine (e.g. BGV A 3,
"Electrical Installations and Equipment").
Emergency stop functions and equipment must not be made ineffective.
See relevant standards (e.g. DIN EN 418).
Your installation must be equipped in accordance to the EMC guidelines
so that electromagnetic interferences can be eliminated.
Operating 750 Series components in home applications without further
measures is only permitted if they meet the emission limits (emissions of
interference) according to EN 61000-6-3. You will find the relevant
information in the section on "WAGO-I/O-SYSTEM 750" "System
Description" "Technical Data".
Please observe the safety measures against electrostatic discharge
according to DIN EN 61340-5-1/-3. When handling the modules, ensure
that the environment (persons, workplace and packing) is well grounded.
The relevant valid and applicable standards and guidelines concerning the
installation of switch cabinets are to be observed.

8 • Important Notes
Symbols
WAGO-I/O-SYSTEM 750
I/O-Modules
1.3 Symbols
Danger
Always observe this information to protect persons from injury.
Warning
Always observe this information to prevent damage to the device.
Attention
Marginal conditions that must always be observed to ensure smooth and
efficient operation.
ESD (Electrostatic Discharge)
Warning of damage to the components through electrostatic discharge.
Observe the precautionary measure for handling components at risk of
electrostatic discharge.
Note
Make important notes that are to be complied with so that a trouble-free and
efficient device operation can be guaranteed.
Additional Information
References to additional literature, manuals, data sheets and internet pages.

Important Notes •9
Safety Information
WAGO-I/O-SYSTEM 750
I/O-Modules
1.4 Safety Information
When connecting the device to your installation and during operation, the
following safety notes must be observed:
Danger
The WAGO-I/O-SYSTEM 750 and its components are an open system. It
must only be assembled in housings, cabinets or in electrical operation rooms.
Access is only permitted via a key or tool to authorized qualified personnel.
Danger
All power sources to the device must always be switched off before carrying
out any installation, repair or maintenance work.
Warning
Replace defective or damaged device/module (e.g. in the event of deformed
contacts), as the functionality of field bus station in question can no longer be
ensured on a long-term basis.
Warning
The components are not resistant against materials having seeping and
insulating properties. Belonging to this group of materials is: e.g. aerosols,
silicones, triglycerides (found in some hand creams). If it cannot be ruled out
that these materials appear in the component environment, then the
components must be installed in an enclosure that is resistant against the
above mentioned materials. Clean tools and materials are generally required
to operate the device/module.
Warning
Soiled contacts must be cleaned using oil-free compressed air or with ethyl
alcohol and leather cloths.
Warning
Do not use contact sprays, which could possibly impair the functioning of the
contact area.
Warning
Avoid reverse polarity of data and power lines, as this may damage the
devices.
ESD (Electrostatic Discharge)
The devices are equipped with electronic components that may be destroyed
by electrostatic discharge when touched.
Warning
For components with Ethernet/RJ45 connectors:
Only for use in LAN, not for connection to telecommunication circuits

10 • Important Notes
Font Conventions
WAGO-I/O-SYSTEM 750
I/O-Modules
1.5 Font Conventions
italic Names of paths and files are marked in italic.
e.g.: C:\Programs\WAGO-IO-CHECK
italic Menu items are marked in bold italic.
e.g.: Save
\ A backslash between two names characterizes the
selection of a menu point from a menu.
e.g.: File \ New
END Press buttons are marked as bold with small capitals
e.g.: ENTER
< > Keys are marked bold within angle brackets
e.g.: <F5>
Courier The print font for program codes is Courier.
e.g.: END_VAR
1.6 Number Notation
Number code Example Note
Decimal 100 Normal notation
Hexadecimal 0x64 C notation
Binary '100'
'0110.0100'
Within inverted commas,
Nibble separated with dots
1.7 Scope
This manual describes the Special Module 750-645
2AI/2DO VIB VRMS/SPM Multi of the modular WAGO-I/O-SYSTEM 750.
Handling, assembly and start-up are described in the manual of the Fieldbus
Coupler. Therefore this documentation is valid only in the connection with the
appropriate manual.

Condition Monitoring •11
Tasks and Options
WAGO-I/O-SYSTEM 750
I/O-Modules
2 Condition Monitoring
2.1 Tasks and Options
The growing cost pressure within the global competition increasingly forces
companies to maximize existing saving potentials and to implement measures
for more efficiency. In the maintenance sector this means the assurance of a
fault free production process, the avoidance of unscheduled machine down-
time and the optimum exploitation of the installation lifespan.
For the realization of these goals, online condition monitoring systems are of
paramount importance. Faults can be diagnosed early, maintenance measures
scheduled for the optimum timelines and unexpected operational shuts-downs
can be avoided.
The continuous registration of the machine health condition via the fieldbus
permits an early analysis and reaction prior to the actual occurrence of
damages.
For this purpose, WAGO offers the WAGO-I/O-SYSTEM function modules
for recording and processing of the relevant parameters, such as current,
temperature, standard signals and machine vibrations.
Typical applications will be all standard machines, such as electric motors,
ventilators, pumps, air conditioners, etc.
2.2 Machine Condition Monitoring with VIB-I/O Modules
2.2.1 Fundamentals
2.2.1.1 Vibration Severity
The vibration severity is defined as the largest effective value of the vibration
speed occurring at functionally important locations, in a frequency range of 2
or 10 to 1000 Hz. The vibration severity is an energetic mean value of all
vibration components within a wide and comparatively low frequency range.
The vibration severity is relative to the energy level of the machine vibration
and thus a suitable indicator for the vibration forces acting on a machine.
2.2.1.2 ISO 10816-3
The following illustration shows the criteria for an analysis of the vibration
severity values. The classification depends on the capacity and installation of
the machine.
The frequency range to be recorded is to be selected according to the machine
RPM (10 Hz to 1000 Hz for > 600 RPM, 2 Hz to 1000 Hz for > 120 RPM).
Group 1: large machines; 300 kW to 50 MW capacity

12 • Condition Monitoring
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
Group 2: medium machines; 15 kW to 300 kW capacity
Group 3: pumps, indirect drive
Group 4: pumps, direct drive
A
B
C
D
Direct Drive Intermediate Shaft /
Belt Drive
rigid rigid rigid rigid
soft soft soft soft
Machine Base
Group
Machine Type
Pumps
radial, axial, diagonal
P > 15 KW
medium-size
Machines
15 KW < P < 300 KW
large-size
Machines
300KW<P<50MW
Group 4 Group 3 Group 2 Group 1
Motors
160mm<H<315mm
Motors
315 mm < H
Vibration Velocity (RMS)
(10 - 1000 Hz, r > 600 1/min)
(2 - 1000 Hz, r > 120 1/min)
mm/s
0.71
1.4
2.3
2.8
3.5
4.5
7.1
11
Fig. 2.2.1-1: Scaling system ISO 10816-3 g064530e
A: newly commissioned
B: unlimited long-term operation admissible
C: short-term operation admissible
D: vibration causes damages
The machine condition is determined by searching for the measured vibration
speed in the right column and reading the corresponding machine class at the
lower axis.
Derived measures
A, B: Continuous measuring in regular time intervals.
C: Determination of the cause of vibration and exact observation of the
machine. Plan for shut-down.
D: Immediate measures are required: localization of the cause, machine
shut-down and problem correction.

Condition Monitoring •13
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
2.2.2 Roller Bearing Analysis
The VIB-I/O module uses the shock pulse method to analyze the roller
bearing. This method provides the measurement of mechanical shock
impulses. They arise during operation from the contact between the roller
bearings and the rolling path in the load zone and spread in waves in the
material. The signals measured during the rolling process divide in the carpet
value and the peak value. With increasing deterioration of the measuring state,
the distance between those two values will increase. The VIB-I/O module
measures the carpet value, as well as the peak value. With the analysis of these
two parameters, damages can be detected very early. Shock impulses are
influenced by the rolling speed of the roller bearings.
The subsequently used scale in three parts for the evaluation of the roller
bearing state ('good', 'limited' and 'poor') shall serve only as a pictorial
example. The actual limits boundaries between 'good', 'limited' and 'poor'
roller bearing condition can differ strongly from bearing to bearing, depending
on the design and operational conditions. A reliable diagnosis of a bearing
condition is only possible with a trend analysis over longer periods of time.
2.2.3 Shock Impulses
Shock impulses are momentary impulses arising from mechanical damages to
roller bearings or the bearing surfaces. The severity of these shock impulses
depends, amongst others, from the rolling speed of the roller bearings. Shock
impulses occur during machine operation as frequently as vibrations. They can
be traced to various causes, e.g., shocks due to harsh handling or explosions.
The deciding factor is their short duration. A shock impulse may be defined,
as e.g., transmission of kinetic energy to a system in a relative short time.
Shock impulses occur in bearings. There, they are caused by the contact
between the roller bearings and the rolling path of the load zone. Because
both, the surface of the rolling path and the surface of the roller bearing are
rough, signals are generated by the collision at locations where the lubricant
layer is not thick enough and these roughness peaks meet. These signals
spread in waves and are transmitted to all other surrounding parts via the
bearing.
2.2.3.1 Measuring Shock Impulses
The acceleration sensor mounted to the load zone of the bearing is actuated
through shock impulses at its natural resonance of approx. 30 kHz. A high
band filter is used to suppress low frequency portions, - such as those caused
by alignment or balancing errors. The remaining signal portions are processed
by the computer to obtain various shock impulse parameters that are described
in the following pages.

14 • Condition Monitoring
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
2.2.3.2 Shock Impulse Evaluation
The following scale for the evaluation of shock impulses has been created.
The measured shock impulses are classified here in the categories of the
bearing state, from 'good, to 'limited' and finally to 'poor'.
60
dB
N
100%
40
20
050%
poor
limited
good
Fig. 2.2.3-1: Evaluation of shock impulses g064510e
The illustration shows the progress of a trend measurement from originally
good values to poor values (bearing damage).
This provides a quick and clear overview of the evaluation of the
measurement results, without complex terminology or calculation.
Note
Because roughness is rolled into the surface during operation, but new damages
also occur, the measured values may strongly rise or decline for short periods
of time. For this reason, the "snapshot" of a measured value is less
representative than a trend measurement and trend monitoring over a longer
period of time.
2.2.3.3 The Shock Impulse Carpet Value
Roughness in the surface can cause a quick sequence of low shock impulses,
together creating the carpet value of a bearing. This is the basic noise which is
audible through a screwdriver pressed to the bearing. The carpet value is
measured in decibel (dBc = decibel carpet value). The carpet value ( )
provides information to the lubrication of a bearing, the assembly condition
and the different load of a bearing (e.g. due to alignment errors). The carpet
value directly corresponds to the lubricant thickness between roller bearings
and rolling path. If the rolling path and roller bearings are separated by a
complete and sufficient lubrication layer, the carpet value is low. This is
shown in the following diagram.

Condition Monitoring •15
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
0
20
40
60
dB
N
Time
poor
limited
good
Fig. 2.2.3-2: Low carpet value g064518e
The carpet value rises when the lubrication layer decreases and rolling path
and roller bearing touch at more and more locations. The following diagram
shows an increased carpet value.
0
20
40
60
dB
N
Time
poor
limited
good
Fig.. 2.2.3-3: Increased carpet value g064519e
The carpet value helps to pinpoint the cause for limited or poor operating
conditions.
2.2.3.4 The Shock Impulse Peak Value
Bearing damages (i.e., relatively large roughness of the surfaces) result in
individual, very high shock impulses (see illustration below). In some cases,
this can be heard through a screwdriver pressed to the bearing. The highest
shock impulse values measured at a bearing are called peak value (or
maximum value) and are shown in dBM (decibel maximum value). The peak
value ( ) provides information to the operating conditions of a bearing and
already existing bearing damages. The following diagram shows shock
impulses indicating a bearing damage.

16 • Condition Monitoring
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
0
20
40
60
dB
N
Time
poor
limited
good
Fig. 2.2.3-4: Shock impulses at bearing damage g064520e
2.2.4 Damage History
2.2.4.1 Three Stages to Evaluate a Roller Bearing State
By performing continuous shock impulse measurements, changes in the
bearing condition can be easily detected. The operating time starts at 0 % with
the installation of the bearing and ends with the bearing damage at 100 %. The
diagram below shows the shock impulse values (only peak values) of a normal
roller bearing. 'Normal' means here that the installation and lubrication are
proper and that the bearing is under constantly distributed load. The
continuous increase of the shock impulse values can be traced to material
fatigue and consequential bearing damage.
60
dB
N
100%
40
20
050%
poor
limited
good
Fig. 2.2.4-1: Lifespan curve g064510e
Low deviations of the measured values are quite normal. They can be caused
by temperature changes, changes in bearing load, the time passed since the last
lubrication and other influences during operation.

Condition Monitoring •17
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
Deciding factor for the planning of bearing changes is the trend measurement
and change analysis.
Continuous shock impulse measurements clearly show changes in the bearing
condition during operation.
Note
New bearings may require a break-in time, during which the base noise is
decreasing.
2.2.4.2 The Evaluation Scale
The roller bearing evaluation scale is divided in three stages:
1. Good operating condition
2. Limited operating condition
3. Poor operating condition
The subsequent diagrams show how carpet value and peak value can develop.
2.2.4.2.1 Good Operating Condition
The diagram below shows a bearing in a good operating condition. The low
carpet value indicates that the installation, lubrication and load are normal. A
peak value that is only little higher than the carpet value confirms this
evaluation.
60
dBN
40
20
0
Time
poor
limited
good
Fig. 2.2.4-2: Good operating condition g064511e
A low carpet value indicates that the installation, lubrication and load are
normal.
2.2.4.2.2 Limited Operating Condition
A significant increase of both values is a first warning signal. A bearing
damage in the making only appears during limited operating condition. The

18 • Condition Monitoring
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
peak value reaches increased values and the difference between peak values
and carpet value rises (see diagram below).
60
dBN
40
20
0
Time
poor
limited
good
Fig. 2.2.4-3: Limited operating condition g064512e
A visible increase in the peak values and a rising difference between carpet
value and peak values are a sure indication for a bearing damage in progress.
2.2.4.2.3 Poor Operating Condition
Peak values in poor operating condition, a large distance between peak values
and carpet values and a possible increase in the carpet value, indicate the
presence of a bearing damage.
60
dB
N
40
20
0
Time
poor
limited
good
Fig. 2.2.4-4: Poor operating condition g064513e
When the peak values are in poor operating condition and the peak values are
approx. three times the carpet value, the risk of a bearing damage is very high.

Condition Monitoring •19
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
2.2.5 Typical Shock Impulse Diagrams
2.2.5.1 Bearing in Good Condition
Peak values between 0 dBn and 20 dBn do not require a further analysis. The
bearing is in good condition. Brand-new bearings and small needle roller
bearings may show values below 0 dBn. Such low values, however, should be
verified since they could be caused by a wrong measuring position or a faulty
measurement.
60
dB
N
40
20
0
poor
limited
good
Time
Fig. 2.2.5-1: Bearing on good condition g064514e
Note
Extremely low measured values may be frequently caused by wrong measuring
locations or an erroneous measuring position.
2.2.5.2 Bearing Damage of Foreign Matter in the Lubricant
Occasional high peak values beyond 35 dBn and a low carpet value indicate
that a bearing damage is in progress or that foreign matter is contained in the
lubricant. The bearing should be re-lubricated or the lubricant requires
analysis, prior to the decision of a bearing exchange.
60
dBN
40
20
0
Time
poor
limited
good
Fig. 2.2.5-2: Bearing damage or foreign matter in the lubricant g064515e

20 • Condition Monitoring
Machine Condition Monitoring with VIB-I/O Modules
WAGO-I/O-SYSTEM 750
I/O-Modules
2.2.5.3 Installation Errors or Insufficient Lubrication
A high carpet value and a peak value insignificantly above, but still in the
limited range, indicate either an installation error when the bearing was
installed, or insufficient lubrication. The bearing should be re-lubricated and
measured again after some hours. If the lubrication was insufficient, the values
should decrease. If the bearing was installed wrongly, the measurement values
will remain the same.
60
dBN
40
20
0
Time
poor
limited
good
Fig. 2.2.5-3: Installation errors or insufficient lubrication g064516e
2.2.5.4 Dry-Run or Cavitation
In this diagram, the carpet value and the peak value are very high. This can be
caused by dry-run of the bearing or cavitation at a pump. If the cause was dry-
run, a re-lubrication of the bearing results in decreased values. In the case of
cavitation, the values close to the pump enclosure will be the highest, or will
oscillate with the operating point (pressure).
60
dB
N
40
20
0
Time
poor
limited
good
Fig. 2.2.5-4: Dry-run or cavitation g064517e