NSK Bruel & Kjaer Vibro ds821 Series User manual

Keep accessible for future reference
Instructions
Displacement sensor system series
ds821
Measuring range 4 mm

Copyright © 2022 Brüel & Kjær Vibro GmbH
All rights to this technical documentation remain reserved.
Any corporeal or incorporeal reproduction or dissemination of this technical documentation or making this
document available to the public without prior written approval from Brüel & Kjær Vibro GmbH shall be
prohibited. This also applies to parts of this technical documentation.
Instructions Sensor ds821 4 mm, C104958.002 / V04, en, date of issue: 07.03.2022
Brüel & Kjær Vibro GmbH
Leydheckerstrasse. 10
64293 Darmstadt
Germany
Phone: [phone]
Fax: [phone]
Brüel & Kjær Vibro A/S
Lyngby Hovedgade 94, 5 sal
2800 Lyngby
Denmark
Phone: [phone]
Fax: [phone]
BK Vibro America Inc
1100 Mark Circle
Gardnerville NV 89410
USA
Phone: [phone]
Hotline
Phone: [phone]
E-Mail: [email protected]
Homepage
www.bkvibro.com
Corporate E-Mail
[email protected]

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Brüel & Kjær Vibro │Instructions Sensor ds821 4 mm
Table of Contents
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Table of Contents
1Safety........................................................................................................................5
1.1 Disclaimer..............................................................................................................................................5
1.2 Intended usage......................................................................................................................................5
1.3 Limitations.............................................................................................................................................6
1.4 General information..............................................................................................................................6
1.5 User Qualification .................................................................................................................................6
1.5.1 Recommendations to User.....................................................................................................................................6
1.5.2 Prohibition of Unauthorized Modifications ..............................................................................................................7
1.6 Information on delivery and transport................................................................................................7
1.7 Information on assembly and disassembly.......................................................................................7
2Product description.................................................................................................9
2.1 Basic function.......................................................................................................................................9
2.2 Components of the displacement sensor system.............................................................................9
2.3 Nominal overall length of the displacement sensor system..........................................................10
3Delivery, storage, transport..................................................................................11
3.1 Delivery................................................................................................................................................11
3.2 Storage and transport ........................................................................................................................11
4Installation..............................................................................................................12
4.1 Assembling the displacement sensor..............................................................................................13
4.1.1 Displacement sensor for front-side mounting.......................................................................................................13
4.1.2 Displacement sensor for rear-side mounting........................................................................................................14
4.2 Assembling the driver (oscillator/demodulator)..............................................................................14
4.2.1 Mounting on hat-rail..............................................................................................................................................14
4.2.2 Screw mounting....................................................................................................................................................15
4.3 Connect the components together ...................................................................................................16
4.3.1 Connecting and disconnecting plug connections..................................................................................................16
4.3.2 Connection via extension cable............................................................................................................................16
4.3.3 Direct connection..................................................................................................................................................16
4.4 Setting up the measuring chain and the displacement sensor .....................................................17
4.4.1 Measurement set-up ............................................................................................................................................17
4.5 Electrical connection..........................................................................................................................18

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5Functional check ...................................................................................................19
5.1 Quick check.........................................................................................................................................19
5.2 Troubleshooting..................................................................................................................................19
6Disassembly...........................................................................................................21
6.1 Disconnecting the connecting plugs................................................................................................21
6.2 Driver disassembly.............................................................................................................................21
6.2.1 Disassembling driver with assembly adapter on hat-rail.......................................................................................21
6.2.2 Disassembling driver with assembly adapter, screw-mounted.............................................................................21
6.3 Replacing displacement sensor system components....................................................................21
7Disposal..................................................................................................................22
8Technical data........................................................................................................23
8.1 Non-contacting displacement sensor system Series ds821..........................................................23
8.2 Dimensioning of assembly adapter..................................................................................................24
8.3 Environmental requirements.............................................................................................................25
8.3.1 Reliability of the displacement sensor in different media......................................................................................25
8.3.2 Properties of the measuring track.........................................................................................................................25
8.3.3 Required clearances and minimum distances for displacement sensors .............................................................26
8.4 Transfer characteristics.....................................................................................................................27
8.4.1 Characteristic curve for distance measurement [GAP / V]....................................................................................27
8.4.2 Characteristic curve for vibration measurement [ISF / mV/μm] ............................................................................27
8.4.3 Deviation from best fit straight line [DSL / μm]......................................................................................................27
9Measurement report..............................................................................................28
10 Declaration of conformity .....................................................................................29
11 Simplified diagram................................................................................................. 30

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Brüel & Kjær Vibro │Instructions Sensor ds821 4 mm
Safety
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1 Safety
NOTE!
This manual is a part of the product. Read the manual carefully before using the product
and keep it accessible for future use.
CAUTION!
This symbol warns of dangerous situations which can result from misuse of the product.
NOTE!
This symbol provides general and useful information for using the product.
1.1 Disclaimer
Observing this technical documentation is a basic requirement for the proper and safe operation of
the product. We accept no liability for personal injury, damage to property or financial loss caused by
failure to observe this technical documentation. In such cases, any liability for material defects is
excluded.
1.2 Intended usage
The eddy-current displacement sensor system is intended solely for measuring mechanical distances
and oscillations and is used primarily for the condition monitoring of slide bearings or rotating shafts.
The use of the measuring chain is indoors or outdoors, when the driver is installed in a suitable
protective housing.
If sensors and cables are used in a way not described in the relevant user manuals, function and
protection may be impaired and serious personal damage, death or serious, irreversible injuries may
result.
•Exclusively use sensor as specified in data sheet. Any use other than specified is considered
inappropriate. Brüel & Kjær Vibro does not assume any liability for damages resulting from
inappropriate use. The user is solely responsible.
•Mounted sensors must not be used as steps.
•Ensure that system is exposed only to admissible environmental influences specified in
technical system data sheet.
•Maintain electrical equipment in regular intervals. Remedy defects, e.g. loose wires, defective
connectors, immediately.

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Hot surfaces
•In line with the user manuals, sensors and cables can be operated in extensive ambient
temperature ranges, whereby they can become hot through self-heating on housing walls and
can produce burning.
•When mounted at external heat or cold sources (e.g. machine parts), systems, sensors and
cables can adopt dangerous temperatures, whereby burning, among other things, can occur in
the event of contact.
1.3 Limitations
The eddy-current displacement sensor system may be used only within the scope defined by the
technical specifications.
Limitations of the user manual
Not all assembly and connection options are described in this manual.
1.4 General information
Never put damaged products into operation. Immediately report any damage.
1.5 User Qualification
Ensure that all work in conjunction with our systems is performed by skilled, expert and authorized
workers (for ATEX systems according to EN 60079-14). Among these works are:
Installation and Commissioning
Installation and commissioning primarily concern work on electrical equipment. These works may be
performed exclusively by electricians or workers instructed and supervised by an electrician in
accordance with electrotechnical regulations/directives.
Change of System Specification
Any change of system specification has its effects on monitoring process with stationary systems and
on the measuring sequence with portable measuring systems.
1.5.1 Recommendations to User
If the use of the system in conjunction with machines or plant sections can produce risks outside of
Brüel & Kjær Vibro's responsibility, the user is expected to prepare and distribute safety technical
instructions or warnings and to ensure that the personnel concerned has received and understood it.
CAUTION!
If system is integrated into a machine or designed to be assembled, commissioning must
not take place until the machine the system is to be integrated in conforms to the EC
directives.

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Safety
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1.5.2 Prohibition of Unauthorized Modifications
System and accessories must not be changed neither in construction nor safety technology without
the express consent of Brüel & Kjær Vibro. Any unauthorized modification excludes Brüel & Kjær
Vibro's liability for resulting damages.
1.6 Information on delivery and transport
CAUTION!
Protect the displacement sensor system from shocks, dust and dirt during storage and
transport. Protect the sensor tip using the supplied protective rubber cap.
1.7 Information on assembly and disassembly
NOTE!
To ensure that the displacement sensor system is functioning properly, do not change
the physical length of any of the system cables.
You must also ensure that the components used, the displacement sensor and the
extension cable, add up to a nominal system length of 5 m, 10 m or 25 m.
CAUTION!
Danger of injury through moving machine parts. Shut down the plant before installing the
displacement sensor.
CAUTION!
Live components can cause the driver to become defective. Close the electrical
connection and apply voltage only once all parts of the displacement sensor system
have been connected correctly.
NOTE!
The driver housings may not contact each other or any other conductive parts.

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Assembly of the sensor:
CAUTION!
The ceramic sensor tip is sensitive to shock. Transport and store the displacement
sensor only with the included protective rubber cap. Always keep the protective rubber
cap for later use.
To avoid damage, make sure, especially during assembly and while operating the
machine, that the sensor tip does not come into contact with other objects.
Loose ceramic particles can lead to damage within the machine.
Check the tip of the sensor for damage before every assembly. Never install a defective
sensor.
Assembly, disassembly or replacement of components:
NOTE!
Never pull the cable to open the connection. Doing so may damage the cable and the
connector ends.

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Product description
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2 Product description
Observe the safety information in chapter "Safety"!
2.1 Basic function
The displacement sensor systems of the ds82x family are based on the non-contacting eddy current
measurement process. The distance is measured between the tip of the displacement sensor and an
electrically conductive surface and sent via a proportional voltage signal to a subsequent electronic
monitor. This records the status of the rotating shafts as a part of surveillance of the machine.
2.2 Components of the displacement sensor system
The eddy-current displacement sensor system consists of the components of displacement sensor
with an integrated cable, an optional separate extension cable and the driver (oscillator/demodulator).
The name of a component is a combination of the series name ds821 and the component designation
(mc = complete system, ds = displacement sensor, ec = extension cable or od = driver). Each series
is available in system lengths of 5 m, 10 m and 25 m.
Figure 2-1) Example non-contacting displacement sensor system Series ds821
1.
Driver ds821.od13x
2.
Extension cable ds821.ec30x
3.
Colour coding: red denotes a measuring range of 4 mm
4.
Assembly adapter
5.
Displacement sensor ds821.ds300x

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2.3 Nominal overall length of the displacement sensor system
The nominal system length (N) refers to the length of the components displacement sensor (P) and
extension cable (L). The optional extension cable is required whenever the length of the displacement
sensor is 0.5 m or 1.0 m and with the help of the additional extension cable must be extended to the
nominal system length of 5 m, 10 m or 25 m.
If the displacement sensor already has the nominal system length, no additional extension cable is
required. In this case, the displacement sensor system consists only of the components displacement
sensor and driver.
Example: correct installation for a nominal length N of 5 m:
P = 0,5 m L = 4,5 m P+L = 5,0 m = N
Example of incorrect installation for a nominal length N of 5 m:
P = 0,5 m L = 4,0 m P+L = 4,5 m ≠N
It should be N = 5.0 m. The nominal overall length has not been complied with.

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Delivery, storage, transport
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3 Delivery, storage, transport
Observe the safety information in chapter "Safety"!
3.1 Delivery
Check the packaging for damage upon delivery and make sure that the contents are complete.
Components included in scope of supply:
Supplied
components
Displacement
sensor
Extension
cable
Driver
Complete
displacement
sensor system
Displacement sensor
X
X
Protection cap
X
X
2 nuts1
X
X
1 sealing ring2
X
X
Extension cable3
X
X
Driver
X
X
Assembly adapter
X
X
Acceptance test
certificate
acc. to DIN EN
10204
X
X
X
X
Measurement
protocol
(works calibration)
X
Instruction
X
X
X
X
Table 3-1) Components included in scope of supply
3.2 Storage and transport
We recommend storing the system in its original packaging. The following conditions must be
observed:
Stacking height: max. 6 packages
Storage temperature: -20 °C to +70 °C
Humidity max. 75%
Packaging dimensions
Displacement sensor system complete (max. 3 parts):
Internal dimensions (WxDxH): 235 x 165 x 180 mm
In the case of single parts (only 1 or 2 parts):
Internal dimensions (WxDxH): 235 x 165 x 125 mm
1
not available for ds3003 (reverse mount sensor)
2
only available for ds3003, (reverse mount sensor), operating temperature range for o-ring -40 °C to +180 °C,
for lower temperatures down to -55 °C o-ring (silicone) on request.
3
not available if the length of the displacement sensor with integrated cable corresponds to the nominal system length of 5 m or 10 m.

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4 Installation
Read the safety information in the chapter "Safety" before installation. To assemble the displacement
sensor system, proceed in the following order:
•4.1 Assembling the displacement sensor
•4.2 Assembling the driver (oscillator/demodulator)
•4.3 Connect the components together
•4.4 Setting up the measuring chain and the displacement sensor
•4.5 Electrical connection
Requirements:
•The displacement sensor system is complete (see “Table 3-1) Components included in scope
of supply” on page 11).
•The overall length of the measuring system neither exceeds nor falls below the nominal length.
•The required clearances and the width of the measuring track are considered
(8.3.2 Properties of the measuring track und 8.3.3 Required clearances and minimum
distances for displacement sensors)
•Required clearances and minimum distances for displacement sensors.
•The sensitivity of the target material is known.
Recommended accessories for trouble-free operation:
•Install the driver in a housing/control cabinet. For this purpose, the protective driver housings
AC-2126 for up to 3 drivers and AC-2127 for up to 6 drivers are recommended.
•Use shielded signal wiring (preferably AC-1112) between the driver and connected electronics.
The connection cable has to be heat-resistant at least + 85 °C.
•Install the sensor cable between machine housing and driver housing in a protective steel
conduit.
•Install the sensor cable between machine housing and driver housing in a protective steel
conduit.

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Installation
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4.1 Assembling the displacement sensor
4.1.1 Displacement sensor for front-side mounting
The front side-mountable displacement sensors are supplied with two nuts. You can use these nuts to
lock it in place after adjustment (4.4 Setting up the measuring chain and the displacement sensor).
Depending on the application, the sensor can be mounted forward-facing either within a machine or
outside of a machine or through the machine housing. To avoid measurement errors, we recommend
in all cases that the sensor be mounted with the help of a suitable sensor holder. The sensor holder
must be mounted in a position where it cannot move relative to the object to be measured during
machine operation.
1.
Remove the protective cap from the sensor tip.
2.
Attach the displacement sensor using a sensor holder suitable for the chosen type of
assembly.
3.
Position the sensor so that it lies vertically to the measuring track.
4.
To avoid damage, make sure that the tip of the sensor does not touch the measuring object.
Adjust the sensor through the display of the measured gap voltage.
5.
Install the extension cable. For fixing with cable clamps, we recommend the use of a suitable
protective conduit.
6.
For assembly within the machine:
Seal the opening in the housing with a bulkhead receptacle to prevent medium inside the
machine (e.g. gas or oil) escaping to the outside. We are not liable for damage resulting from
an inexpert assembly.

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4.1.2 Displacement sensor for rear-side mounting
The sensor for rear-side mounting is assembled with the help of a sensor holder which preferably
includes an integrated bulkhead receptacle.
•Fix the displacement sensor using a retainer that is appropriate for the type of installation.
We recommend using the holder AC-101/AC-3101.
4.2 Assembling the driver (oscillator/demodulator)
Assemble either:
•with assembly adapter on a hat-rail
•with assembly adapter via screw mounting on a firm surface
4.2.1 Mounting on hat-rail
*For mounting on a hat-rail, the mounting tabs for screw mounting can be separated at the predetermined breaking point.
1.
For screw mounting, break off both tabs and attach the driver with the assembly adapter by
sliding it into place (figure ).
2.
Affix the assembly adapter to a hat-rail (DIN EN 60715 TH35): Place rear part of the assembly
adapter (see figure above, item A) onto the guides of the hat-rail and press driver and adapter
downwards until the adapter clicks into place (figure ).
You need to secure the installed driver against misalignment with hat-rail end clamps. The hatrail end
clamps are included with our recommended protective driver housings AC-2126 for up to 3 drivers,
and AC-2127 for up to 6 drivers.

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Installation
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4.2.2 Screw mounting
NOTE!
The screws for the installation are not included in the delivery contents.
A suitable surface of at least 7x10 cm is required for screw mounting:
•Solid metal: ..............Solid metal: M4x12 A2-70
..................................2 washers A2, ................ ...................inner diameter 4.5 mm
.................................. ................... .................... ...................Depth of thread: 12 mm
•Steel: ........................2 sheet metal screws A2
..................................2 washers A2, ................ ...................inner diameter 4.5 mm
..................................Steel thickness 1.2…1.4 mm ............. Core hole diameter: 3.3 mm
•Aluminium ................2 sheet metal screws A2
..................................2 washers A2, ................ ...................inner diameter 4.5 mm
..................................Aluminium thickness 1.2…1.4 mm ..... Core hole diameter: 3.4 mm
1.
Mark the positions for both drill holes (section 8.2 Dimensioning of assembly adapter).
2.
Drill two mounting holes.
3.
Connect the assembly adapter with the driver.
4.
Mount the assembly adapter in the mounting surface with two screws and the washers using
the mounting tabs and secure (e.g. Loctite 243 medium strength, Loctite 270 high strength):
5.
Tighten screws alternately.

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4.3 Connect the components together
Connection options:
•Connection via extension cable
•Direct connection
4.3.1 Connecting and disconnecting plug connections
The connector ends of the displacement sensor and the extension cable feature self-latching
plug connections. They are plugged together, and not joined by a screw connection.
To assemble, observe the following order:
1.
Hold one of both plug connector ends in each hand.
2.
Push both plug connectors together until they audibly click into place.
Push both plug connectors together until they audibly click into place.
1.
Push both plug connectors together until they audibly click into place.
2.
Pull on the silver serrated part of the plug to disconnect the connection.
4.3.2 Connection via extension cable
1.
Connect the extension cable with the integrated cable of the displacement sensor.
2.
Connect the extension cable to the driver.
4.3.3 Direct connection
➔Connect the displacement sensor directly to the driver.

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Installation
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4.4 Setting up the measuring chain and the displacement sensor
The displacement sensor should be adjusted when the rotor is stationary.
4.4.1 Measurement set-up
As a rule, a displacement measuring chain is adjusted with the help of a voltmeter and the "operating
voltage". The measuring system is adjusted through the position of the sensor type to the object to be
measured. The displacement sensor is inserted and fixed in place by positioning it in the linear
measuring range (see drawing). To avoid damaging the sensor tip, the prescribed minimum
separation to the shaft (maximum displacement) must be maintained.
The minimum distance to the target must be selected so that even in the event of maximum deflection
of the shaft the distance (axial or relative to the shaft) does not fall below 0.5 mm.
In case of an axial measurement, the axial bearing clearance design and the current position of the
shaft must be considered in order to prevent damage to the sensor tip.
•The displacement sensor system is fully assembled and connected to a power supply and a
monitoring system.
•The physical separation should lie between 0.5 mm and max. 4.5 mm.
➔Switch on the voltage for the driver.
You will obtain an output signal proportional to the measurement distance in the range -2 V…-18 V.
Adjust the separation of the sensor until the required output signal is present.
NOTE!
Use the characteristic curve U [GAP] to determine your minimum distance.

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4.5 Electrical connection
Connect the driver with an electronic monitoring system (e.g. VC-6000) according to the drawing
below.When setting up your measuring system you should observe the following behavior of the
driver.
The heating effect of the driver electronics
During the warm-up phase the heating effect causes a drift in the static distance measurement.
Displacement sensor
system
Operating time
Drift
5 m
≥1 h
≤6 μm
10 m
≥1 h
≤12 μm
25 m
≥1 h
≤24 μm
Four wire connection
Figure 4-1) Connection of the driver to a monitoring system (VC-6000).

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Functional check
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5 Functional check
Observe the safety information in chapter Safety!
5.1 Quick check
After installing the displacement sensor system, you can check the measured values using a digital
multimeter (Ri ≥ 100 kΩ). If the displacement sensor system is in correct operating condition, you will
see the following values:
System lengths
Operating voltage
UB
Output signal USIG
Load resistance of
the electronic
diagnostic
system
RL
Operating current IB
5 m; 10 m
-24 VDC
-2 ... -18 V DC
>100 kΩ
-8,9 mA ±1 mA
25; m
-24 VDC
-2 ... -18 V DC
>100 kΩ
-8,0 mA ±1 mA
5.2 Troubleshooting
If you the readings you receive deviate from these, proceed in accordance with the following
recommended sequence:
Check the output signal
•The output signal USIG < -18 V.
The distance between target and sensor tip lies outside the measuring range.
Adjust the sensor so that it is nearer the target.
•The output signal USIG > -2 V.
Possibly the distance between target and sensor tip is too small. Adjust the sensor to increase
the distance to the target and re-check USIG. If the output signal does not change, the
displacement sensor system is defective. Follow these additional steps.

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Check the displacement sensor and the extension cable:
•Measure the supply voltage IB(terminal 2) with extension cable and displacement sensor
connected. Disconnect the cable connected to the driver (terminal 1) and measure supply
voltage IBagain. If IBchanges by about 1.8 mA, the sensor cable and the displacement sensor
are OK. Otherwise, there is a disruption in the displacement sensor or extension cable.
•Check the resistance of the extension cable and the displacement sensor:
For a 5 m system: Rsensor + Rext. = 8.7 Ω± 0.5 Ω
For a 10 m system: Rsensor + Rext. = 12.1 Ω± 0.5 Ω
For a 25 m system: Rsensor + Rext. = 26. 6 Ω± 2.0 Ω
Otherwise the displacement sensor or extension cable is defective.
Check the driver:
➔Measure the voltage (terminal 2) at the driver without the displacement sensor connected and
without cables. The result you should obtain is IB= -8 mA ±1 mA. Otherwise, the driver is
defective.
➔Measure the voltage (terminal 2) at the driver without the displacement sensor connected and
without cables. The result you should obtain is:
For a 5 m; 10 m system: -7,3 mA ±1 mA
For a 25 m system: -5,6 mA ±1 mA
Otherwise, the driver is defective.