BRUEL & KJAER 1056 User manual

Technical
Documentation
HEADQUARTERS: Brüel&Kjær Sound & Vibration Measurement A/S · DK-2850 Nærum · Denmark
Telephone: [phone] · Fax: [phone] · www.bksv.com · [e-mail]
Local representatives and service organisations worldwide
DC Static Centering Unit Type 1056
English BE1672–14
User Manual
ËBE-1672--yÎ

BE167214 October 2011
DC Static Centering Unit
Type 1056
User Manual

Trademarks
Neutrik and speakON are registered trademarks of Neutrik AG
Copyright 2001 – 2011, Brüel&Kjær Sound & Vibration Measurement A/S
All rights reserved. No part of this publication may be reproduced or distributed in any form, or
by any means, without prior written consent from Brüel&Kjær Sound & Vibration Measurement
A/S, Nærum, Denmark
Safety Considerations
This apparatus has been designed and tested in accordance with IEC/EN61010–1 and
ANSI/UL61010– 1 Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use. This manual contains information and warnings which must be
followed to ensure safe operation and to retain the apparatus in safe condition. Special note should
be made of the following:
Safety Symbols
The apparatus will be marked with this symbol when it is important that you refer to the
associated warning statements given in the manual.
Protective Earth Terminal Hazardous Voltage
Explosion Hazard
The equipment is not designed to be used in potentially explosive environments. It should not be
operated in the presence of flammable liquids or gases.
Warnings
• This equipment must not be used for measurements on circuits directly connected to mains
voltage. Exceeding the specifications of this product may cause permanent damage and/or
cause the operator to be exposed to potentially hazardous voltages
• Switch off all power to equipment before connecting or disconnecting their digital interface.
Failure to do so could damage the equipment
• Whenever it is likely that the correct function or operating safety of the apparatus has been
impaired, it must be made inoperative and be secured against unintended operation
• Any adjustment, maintenance and repair of the open apparatus under voltage must be
avoided as far as possible and, if unavoidable, must be carried out only by trained service
personnel
• Do not dispose of electronic equipment or batteries as unsorted municipal waste
• It is your responsibility to contribute to a clean and healthy environment by using
the appropriate local return and collection systems
• Hazardous substances in electronic equipment or batteries may have detrimental
effects on the environment and human health
• The symbol shown to the left indicates that separate collection systems must be used
for any discarded equipment or batteries marked with that symbol
• Waste electrical and electronic equipment or batteries may be returned to your
local Brüel&Kjær representative or to Brüel &Kjær Headquarters for disposal

Contents
CHAPTER 1
Introduction......................................................................................................... 1
CHAPTER 2
General Description ........................................................................................... 3
2.1 Components......................................................................................................... 3
2.2 Connections......................................................................................................... 3
2.3 Basic Operation ................................................................................................... 4
CHAPTER 3
Operation and Configuration............................................................................. 7
3.1 Mains Supply Connection.................................................................................... 7
3.2 Set up the Power Amplifier .................................................................................. 7
3.3 Firmware Version................................................................................................. 7
3.4 Start-up Configuration.......................................................................................... 8
3.5 Configuration Menu............................................................................................ 11
3.6 Remote Control.................................................................................................. 17
CHAPTER 4
System Setup.................................................................................................... 23
4.1 Typical System Setup........................................................................................ 23
CHAPTER 5
Specifications................................................................................................... 25
CHAPTER 6
Maintenance and Repair.................................................................................. 27

1
Chapter 1
Introduction
DC Static Centering Unit Type 1056 is for controlling the zero position of a vibration/modal
exciter (shaker) and has been designed to work with Brüel& Kjær Modal Exciters Types 4824,
4825, 4826, 4827 and 4828 and matching power amplifiers.
With control characteristics that can be adjusted, Type 1056 is suitable for universal use.
Depending upon which of the Brüel& Kjær modal exciters is connected, DC Static Centering
Unit Type 1056 serves one of two different purposes:
1) In connection with the electromagnet-based Modal Exciters Types 4827 and 4828, Type
1056 is an essential component that provides for armature “suspension” with variable
stiffness and correct centring of the armature relative to the exciter’s housing and the
structure under test. Type 1056 thus ensures “zero” positioning of the armature, ensuring a
full 2-inch peak-to-peak displacement capability.
2) In connection with the permanent magnet-based Modal Exciters Types 4824, 4825 and
4826, Type 1056 is used as an optional unit to apply a pre-tensioning force to the tension
wire (if such a type of stinger is used – traditional push/pull stingers do not require any
pre-tensioning) between the modal exciter and the input transducer*attached to the
structure under test.
DC Static Centering Unit Type 1056 consists of an optical sensor head and a control device
containing a control unit and an actuating and monitoring unit. The actuating and monitoring
unit is for performing the following jobs:
• well-defined switch-on/-off regimes
• well-defined automatic shut-downs when errors occur
• monitoring of maximum vibration displacement
• monitoring of air pressure of an air bearing shaker
Operating conditions and protective functions during operation are indicated by LEDs.
*The input transducer is either a force transducer or an impedance head, that is, a force transducer and an
accelerometer built to form a combined transducer. Note that the use of Brüel & Kjær’s Impedance Head
Type 8001 requires that the structure under test has a dynamic mass of less than 1.5kg for force
measurement errors less than 10%.

DC Static Centering Unit Type 1056 – User Manual2
Optional Connections
Type 1056 can be optionally connected with:
• an SPS interface for remote control
• a remote control or status query via RS–232 connection
• an active hum suppressor via the signal output chain
Rack Mounting
DC Static Centering Unit Type 1056 is designed to fit into a 19-inch standard rack system. It
may be used free standing on its four rubber feet, or in a 19-inch instrumentation rack with its
rubber feet removed.

3
Chapter 2
General Description
2.1 Components
Type 1056 is made up of the following components:
•Optical Sensor Head: The optical sensor head is mounted onto the shaker, that is, it is
detached from the control device. Its job is to monitor the instantaneous position of the
shaker head and, by doing so, also supply the data needed for recognising any possible
exceedance of the maximum admissable vibration displacement (overtravel).
Type 1056 is configured as a PI (proportional-integral) controller thus ensuring that the
zero position is kept constant even if the shaker load is varied. Control speed (stiffness)
and zero position (zero) can be adjusted independently
•Control Device: Generates a DC voltage offset (bias) that is superimposed on the signal
for driving the shaker.
For Type 1056 to work properly, you are required to use a power amplifier capable of
processing DC voltage signals, such as Brüel&Kjær Power Amplifier Types 2732, 2720
and 2721. The signal source (generator) is required to supply a signal that is free from any
DC offset
2.2 Connections
Fig.2.1 Rear panel of Type 1056
230V/50Hz
315mA/T
115V/60Hz
630mA/T
Sensor Signal In Signal Out RS 232 PLC External Config. Memory
090047

DC Static Centering Unit Type 1056 – User Manual4
The following connections are located at the rear of the device:
•Signal Input and Output:
– Input: BNC socket accepting input from signal generator. The input impedance is
>10k
– Output: BNC socket providing generated test signal and DC input to the amplifier
•Optical Sensor Head: Interface (9-pin Sub-D) socket accepting input on modal exciter
armature position either directly coupled to the modal exciter or via power amplifier
•RS–232 interface: Socket for remote control or status queries
•SPS and External Memory module: Sockets for optional connections
•Mains Input: Input socket accepting a female connector. Mains voltage supplied via
Power Amplifier Type 2732, 2720 or 2721
Type 1056 has to be inserted into the signal path between the generator and the power amplifier
– see Chapter 4 for examples of typical setups.
2.3 Basic Operation
2.3.1 Operational Principle
The operation of Type 1056 includes well-defined switch-on and switch-off regimes, thus the
signal inputs will be connected through only after the zero position has been attained. The
inputs will shut-down when an error/malfunction has occurred, wherein the shaker will be
moved softly to a rest position.
If after start-up from overtravel, the shaker head is unable to move within a specified period,
the device will change over to error condition. There is an open-loop detector that will shut the
device down if the control loop is interrupted (for example, if the amplifier fails).
Pressure in the compressed air piping is monitored by means of a pressure sensor. You will not
be able to start the device without pressure. The pressure sensor has to be configured as a
floating pressure switch and is not supplied with Type 1056.
2.3.2 Front Panel Controls and Indicators
Fig.2.2 Front panel of Type 1056
The front panel contains all controls and indicators of the DC Static Centering Unit.
BK
Zero Stiffness
DC Static Centering Unit
Type 1056
START STOP
Position
080295/1

CHAPTER 2
General Description 5
Controls
Press Start to start the device. The shaker head will move into its zero position.
Press Stop to stop the device. The signal inputs will be interrupted and the shaker will move
into its position of rest.
Use the Stiffness control keys to control speed (stiffness) of the device. The appropriate setting
depends on the intended mode of operation of the shaker. Operating the shaker at low
frequencies (<10Hz) will require a lower control speed than at higher frequencies.
Use the Zero control keys to set the zero position of the shaker head. If the knob is in its
vertical position, the shaker is in its mechanical zero position. The zero position of the head can
be shifted in a range of approximately ±10% of maximum vibration displacement around the
mechanical zero position.
LED Indicators
• Three postional LEDs (): Indicate the position of the shaker head in relation to the
set zero position
• Three LEDs indicating operation status:
–Power LED : Indicates that power is supplied to the device. If the power LED
does not light up after the device has started, the internal or external EEProm has
reverted to the manufacturer’s default settings. You must, therefore, check and set the
parameters of the device. See Chapter 3 for configuration information
–Error LED :
When on, indicates an error. The shaker is automatic slowed down to a rest position
When flashing, indicates settling time is running. The shaker head is moving into zero
position
When off, indicates full functionality. The shaker is ready for use and signal inputs are
connected through
–Pressure Fail LED :
When on, indicates no compressed air
When off, indicates compressed air is available
x

DC Static Centering Unit Type 1056 – User Manual6

7
Chapter 3
Operation and Configuration
After connecting the device as described in Chapter 2, you may connect the mains and start
configuration.
3.1 Mains Supply Connection
Use the power cable provided to connect the mains input to the mains output socket of the
amplifier. The use of an extension cable without protective conductor should be avoided for
safety reasons.
Attention! To avoid interference caused by ground loops or different ground potentials, you
must run the power amplifier on the same power line as the DC Static Centering Unit. If this is
not possible, it is recommended to use a “buffer amplifier.”
3.2 Set up the Power Amplifier
When using Power Amplifier Type 2720 or 2721, you must set the amplifier to Voltage Mode.
See the amplifier’s user manual (BE1661 or BE1658, respectively) for instructions on how to
set the mode.
Do not use Power Amplifier Types 2720/2721 in Current Mode together with the DC
Static Centering Unit. Doing so may cause damage to your equipment.
To set up and connect Power Amplifier Type 2732, see the amplifier’s user manual, BE 1662,
for instructions.
3.3 Firmware Version
The firmware version is displayed in the Zero and Stiffness displays for two seconds after
power boot-up. For example, if the Zero displays shows 0and the Stiffness display shows 5,
then the firmware version is 05.

DC Static Centering Unit Type 1056 – User Manual8
3.4 Start-up Configuration
Configuration of Type 1056 is done using the controls on the front panel. These keys navigate
and control a configuration menu that is numbered from 1 to 53. To get started, you only need
to set up a limited number of configuration parameters. A detailed description of the
configuration menu is given in section 3.5.
To configure Type 1056:
1) Ensure that the instrument is in Stop mode.
2) Press Stop, and while holding it down press Start.
3) Keep both buttons depressed for approximately two seconds. The Zero LED indicator will
have a readout value of 1.
4) Use the Zero position control keys to navigate through the menu. The Stiffness LED
indicator will show the current value of the menu.
3.4.1 Configure for Compressed Air
The Pressure Failure LED is disabled at factory setup. If the shaker in use is designed to
function with compressed air, you will need to enable the LED to indicate when there are
errors. To enable, configure the monitor in Menu 9 (see section 3.5 for more information):
• Select 0to switch off monitoring
• Select 1to switch on monitoring
3.4.2 Polarity Check
1) After making all electrical connections, switch on the compressed air (if needed).
2) Switch on the power amplifier.
3) Press Start on Type 1056.
4) Observe the head. If it does not move into its zero position, but instead is pulled into the
magnet, you will have to invert the polarity of the shaker. To do so, do one of the
following:
a) Invert shaker polarity at the output of the power amplifier.
b) Configure the inversion using Type 1056 by selecting 1in Menu 12 (see section
3.5 for more information).
3.4.3 Configure According to Your Power Amplifier
The gain factor of the employed power amplifier has an effect on the control characteristic of
Type 1056. To ensure flawless operation of the DC Static Centering Unit, set up its parameters
in Menu 17 to agree with the internal gain of the power amplifier as shown in Table 3.1.
x

CHAPTER 3
Operation and Configuration 9
Table 3.1 Power amplifier characteristics that determine the setting of the DC Static Centering Unit
for optimal functionality
Note: The stated power output values can be used as a rough basis for assessment in cases
where the power amplifier’s internal gain is not known.
3.4.4 Configure Input and Output Sockets
Configure the Input Socket Using Menu 11
• Select 0for floating input
• Select 1for input signal relative to earth
• Select 2for balanced input
Configure the Output Using Menus 12 and 13
If after a polarity check (see section 3.4.2) you need to invert the polarity, use Menu 12:
• Select 0for ouput not inverted
• Select 1for output inversion
Disturbing influences due to hum pick-up can be reduced effectively by appropriately
configuring the sockets in Menu 13:
• Select 0for output signal relative to earth
• Select 1for active hum suppression
DC Static
Centering Unit
Gain
Power
Amplifier
Gain
Amplifier’s
PowerOutput
(1V input)
Amplifier’s
Power Output
(10V input)
Constant
Factor for
Determining
Transfer
Coefficient (k)
Menu
Selection
4 2.5 – 150VA 12V 2
33–250VA9V2
2 5 6VA 600VA 6V 3
1 10 25VA 2500VA 3V 6
0.66 15 60VA – 2V 10
0.5 20 100VA – 1.5V 14
0.33 25 200VA – 1.1V 21
0.28 35 300VA – 0.88V 25
0.25 40 400VA – 0.75V 28
0.166 60 1000VA – 0.5V 42
0.125 80 1500VA – 0.325V 55

DC Static Centering Unit Type 1056 – User Manual10
3.4.5 Adjust the Mechanical Zero Position
The optical sensor head has to be attached to the shaker such that the head is in its mechanical
zero position when the Zero control on the front panel is set to zero.
• The zero position’s display (bar graph) can be adjusted using Menu 27 and Menu 28.
• The sensor head can be adjusted manually and checked, if no voltage meter is available,
using Menu 52 and Menu 53.
• Fine adjustment of the sensor head can be performed using Menu 35.
Limit the Bar Graph
You can specify the indicating range of the zero position’s bar graph using Menu 27. Selected
values can be from 1to 63.
Adustment of the Bar Graph’s Zero Position
If the zero position is not directly in the centre, you can fine tune the position using Menu 28.
Selected values can be from 1to 33.
Voltage Adjustment of Displacement Measuring System Inputs
To configure input A, use Menu 52. To configure input B, use Menu 53. For both menus, set
the parameter as follows:
• If the voltage is less than 8V, select –1to increase voltage in order to achieve correct
adjustment
• If the voltage is more than 8 V, select 1to decrease voltage in order to achieve correct
adjustment
Fine Adjustment of the Sensor Head
1) Before you fine tune the sensor head, you must have adjusted the bar graph and set the
amplifier and control parameters.
2) Press Start and wait for the alignment of the zero position.
3) Adjust the correct zero position using the Zero position keys.
4) Hold the Start button until the device switches off the zero position controls (about five
seconds).
5) Use the Zero position keys to navigate to Menu 35.
6) Adjust the position as follows:
Firmware version less than 06: Select –99, which has a displacement of 0, a value
corresponding to the mapped ADC value of 0 to 1023 added to the zero position value
Firmware version 06 or greater: Select a value up to 99, which will be directly added
to the zero position value. For example, if the zero position value originally was 0,
then it will change to 0 + the selected setting

CHAPTER 3
Operation and Configuration 11
3.4.6 Configure as a P Controller
If Type 1056 is to be used as a P (proportional) controller – for example when used with modal
shakers for positioning and generation of a bias force – you must first configure Menu 18,
which sets the the I component of control (time constant):
• Select 0if there is no I component (setting for P controller)
• Select 1through 6 if there is an I component. The higher the value, the stronger the I effect
When Type 1056 is used as a P controller, it can be seen as a spring-damper combination, the
transfer coefficient, h(force constant), of which can be adjusted by means of the stiffness
control. If the stiffness control is set to full scale, the transfer coefficient, h, depending on the
selected amplifier, is:
where kis the constant factor according to Table 3.1 and smax is the maximum displacement of
the shaker.
Attenuation can be adjusted in Menu 20 to adapt the system to the current application by
setting the P component:
• Select 0for no P component
• Select 1for a small P component
• Select 2for a strong P component
To avoid any reaction on the shaker, set the frequency to <10Hz and select 2in Menu 20 to
increase attenuation. Of course, the correct setting is dependent on the shaker used.
3.5 Configuration Menu
The configuration menu is for viewing and modifying the settings of Type 1056. The
configuration can be saved in the internal memory or an external memory (EEProms).
Use the Zero position keys to navigate through the menu. See Table 3.2 for an overview of the
menu.
To save settings, use Menu 38 (internal memory only) or Menu 39 (internal and external
memory).
If you want to exit the menu quickly at any point, press Stop for approximately four seconds.
Note that if you do this, all settings entered will be lost and revert to the previous configuration.
hk
smax
-----------=

DC Static Centering Unit Type 1056 – User Manual12
Table 3.2 Overview of the configuration menu
Menu Description Min.
Value Max. Value Quick Guide Factory Setting
1Select overtravel limit couple
(couple 1, 2 or 3).*
Minimum and maximum
values are set per menu
131: Set limits via Menus 2 & 3
2: Set limits via Menus 4 & 5
3: Set limits via Menus 6 & 7
1
2Set minimum overtravel limit,
couple 1 –99 99 Enter a value. –20
3Set maximum overtravel
limit, couple 1 –99 99 Enter a value. If this value and the value of
signal 2 are exceeded, the
zero position control will
shut down and the output
switched off
80
4Set minimum overtravel limit,
couple 2 –99 99 Enter a value. –20
5Set maximum overtravel
limit, couple 2 –99 99 Enter a value. If this value and the value of
signal 2 are exceeded, the
zero position control will
shut down and the output
switched off
80
6Set minimum overtravel limit,
couple 3 –99 99 Enter a value. –20
7Set maximum overtravel
limit, couple 3 –99 99 Enter a value. If this value and the value of
signal 2 are exceeded, the
zero position control will
shut down and the output
switched off
80
8Set TimeOut value forcontrol
action. This is the waiting
period (seconds) within the
shaker must have started
moving after a control action.
If there is no movement,
Type 1056 will shut down
1 99 Enter a value. 10
9Enable pressure monitoring 0 1 0: Monitoring disabled
1: Monitoring enabled 0

CHAPTER 3
Operation and Configuration 13
10 Set the device for horisontal
operation of shaker. If the
shaker is operated in the
horisontal direction, the DC
control signal will not be
ramped down when
switching off
010: No horisontal shaker
1: Horisontal shaker 0
11 Set of LF input 0 2 0: Floating
1: Input relative to earth
2: Balanced input
0
12 Invert the output signal 0 1 0: Output not inverted
1: Ouput inverted 0
13 Set of output signal 0 1 0: Output relative to earth
1: Active hum suppression 0
14 Set the device for operation
with shaker springs 010: Shaker with springs 1: Shaker without springs 1
15 Set the value for step
duration when updating the
DC voltage in controlled
mode. This effects the
control speed.
Duration = value * 10ms
0 99 Enter a value.
0: The fastest setting
99: The slowest setting
0
16 Set the step width (DC
increment) in controlled
mode. This corresponds to
the steps taken by the DAC
and will effect the control
speed
1 99 Enter a value.
1: Will take longest
99: DAC will be set
immediately
1
17 Set the device to agree with
the amplifier.
This setting is critical as the
shaker can be damaged ifan
incorrect selection is made
0 63 Match the device with the
correct amplifier using Table
3.1 and enter a value –
starting with the highest
possible value (30 or more)
60
18 Set the I component of
control. If there is an I
component, the device can
be used as a P Controller
060: No I component
1...6: Increasing I
component from little to
strong effect
2
19 Limit the I component 0 2 0: No limitation
1: Limited to 1V
2: Limited to 2V
0
20 Set the P component in
order to adjust attenuation 020: No P component 1: Small P component
2: Strong P component
1
Menu Description Min.
Value Max. Value Quick Guide Factory
Setting

DC Static Centering Unit Type 1056 – User Manual14
21 Attenuate the LF signal 0 31 0: Strong attenuation
1...31: Decreasing
attenuation. At 31, the AC
signal is supplied to output
without any attenuation
0
22 Determine which stiffness
value to use as default
setting
010: Stiffness value set on the
front panel is used
1: Stored stiffness value is
used
1
23 Set stored stiffness value
(force constant) 0 31 Enter a value. 31
24 Determine which zero
position value to use as
default
010: Zero position value set on
the front panel is used
1: Stored zero position value
is used
1
25 Set stored zero position
value –99 99 Enter a value. 0
26 Invert the bar graph (zero
position) 010: Do not invert bar graph 1: Invert bar graph 0
27 Set the indicating range of
the bar graph (zero position) 0 63 Enter a value. 63
28 Fine adjustment of zero
position in bar graph. This is
used if the zero position is
not in directly in the centre
0 31 Enter a value. 22
29 Select the signal source
(Input overtravel A or B) for
the bar graph, if the bar
graph does not continuously
indicate the zero position.
The setting also effects the
output of the positioning
signal
010: Input overtravel A
1: Input overtravel B 0
30 Set up the device for SPS
remote control.
If this is enabled, you will not
be able to start Type 1056
manually or via RS–232
commands regardless if an
SPS is connected or not
010: Do not use SPS remote
control
1: Use SPS remote control
1
Menu Description Min.
Value Max. Value Quick Guide Factory Setting