Device
Durable sensors for cranes
and heavy vehicles
Ralph Werren (Baumer Group), Ellen-Christine Reiff (Editorial Office Stutensee)
O
utdoor deployment is
one of the most demanding applications for
sensor products. Heat, very
low temperatures, heavy
impacts by shocks and vibrations or water in all its
forms – sensors installed at
cranes and heavy vehicles
in construction or agriculture must be prepared for
the worst but always ensure
absolutely dependable operation. Unlike in stationary
applications, there won’t be
a service team on the scene
immediately in case of an
emergency. The same applies for many other Baumer sensors deployed in mobile applications for liquid
level detection or pressure
and lock control.
The company meets
this challenge with a wide
range of sensor solutions
especially conceived for
deployment at cranes, mobile facilities and heavy vehicles. The sensors master
52
most applications – from
motor and position feedback to strain and liquid level acquisition as for example in hydraulic reservoirs.
Many sensors are also
available with the industrysignificant vehicle bus interface SAE J1939.
Motor feedback
Incremental encoders are
an efficient and economic
solution for speed feedback
at regulated drives. However, to ensure the required
high equipment availability and up time even under harsh outdoor conditions, it should be a heavy
duty product. These configurations excel with massive
light metal cases with special surface protection as
well as large, extremely resilient bearings which endure very high axial and ra-
To ensure the required high equipment availability
and up time even under harsh outdoor conditions,
a heavy duty product should be used such as the
HOG10 encoder series.
CAN Newsletter 3/2011
dial loads. Enhanced electrical insulation of the ball
bearings sustain ably prevents balls and running surface from damage by shaft
currents. Heavy duty encoders feature incremental sensing by opto-ASICs,
shock- and vibration proof integrated electronics, special
seals and are also available
in hollow shaft designs. Reliability under extreme conditions is further backed by
short-circuit proof line drivers with temperature-controlled
high-performance
transistors, specialized filter
circuits for voltage supply
as well as the large, EMC
compliant terminal box turn
able through a 180° angle, a
flexible stator coupling and
massive torque support.
Another important encoder feature is the integrated diagnostic monitoring functionality. The
„enhanced monitoring system (EMS)” is based on a
rapid microprocessor which
consistently monitors the
proper encoder functionalities throughout the entire
speed range. Thus, potential problems will be identified before they arise. Via
the additional alarm output
the master control will receive an error message in
the event of any identified
malfunction. The LED status indicator visualizes the
current encoder activity.
Speed regulated drives
often require more parameters, e.g. speed limit control.
Such tasks are ideally performed by product combinations merging two functionalities in one assembly, for
example an incremental encoder utilized in conjunction
Draw wire encoders
are deployed at heavy
vehicles and cranes
to monitor boom or
outrigger extension.
HS
B
US
fa
er
Int
ce
Inclination sensors are of
growing significance in
heavy vehicles and mobile
facilities, since in ever-increasing automation they
present a substantial contribution to safety. By principle, inclination sensors
are a kind of “electronic water scale” to measure
the inclination angle of vehicles, loading platforms,
outriggers or rotary drill
rigs in relation to the horizontal plane. The absolute inclination sensors of
the GNAMG series feature
a sensing range from 15°
to 60° and dual axis angle
sensing with a 0,001° resolution. Sensor versions with
single axis detection utilize
a sensing range throughout
a 360° angle. In mobile applications, inclination sensors enable communication
via all conventional fieldbus interfaces and come in
an impact-proof metal housing with standard IP67 protection. Sensor mount is by
base plate 99 mm x 60 mm
x 5 mm.
A possible product alternative to pick up the angle of outriggers and loading facilities are magnetic
angle sensors. Alike their
inclination
counterparts,
they detect rotation angles
with 0,09° resolution by the
so
es
pr
CX
Safety at top level
non-contact sensing principle, are very resilient and of
compact design.
The sensor platform
DSRT provides anti-tilt protection without acquiring the
rotation angle. These strain
links measure the surface
strain between the support
surfaces. Strain links are
ideally suited for measurements on rigid structures
and in the appropriate configuration they can be deployed in both cyclic and
static applications.
Draw wire encoders offer versatile application options at heavy vehicles. Encoders with draw
wire assembly convert linear motion into rotary motion when pulling in and out
the cable. Depending on
the application, the rotary
motion is driving an incremental or absolute encoder
which provides the signals
for control evaluation or further processing by controller or digital display.
Draw wire encoders
excel with extreme versatility, are easy to mount and
provide dependable operation even in harsh environments. They are deployed to
register the extension angle
of booms and outriggers at
heavy vehicles and cranes,
telescopic machine arms
and elevating platforms.
Redundant configurations
ensure safety at top level.
When it comes to monitoring of limit positions, inductive sensors are the product
to choose. The IFRR sensor platform proves itself
by robust stainless steel
housing, an extended tem-
LP
with an electronic or mechanical speed switch. The
speed limits for switch on
and off can be programmed
at will or, where required for
reasons of safety, allow for
permanent settings.
LPCXpresso
with CAN MCU
LPCXpresso low cost development tool now
available with LPC11C2x CAN MCU
L
PCXpresso now features the LPC11C2x with
high-speed CAN transceiver and 32-bit LPC1100 MCU
LPC11C2x provide higher code density powered by
Cortex-M0 compared to 8/16-bit microcontrollers
Enable development of a wide range of industrial
networking applications
www.nxp.com/microcontrollers
Interfaces
Device
perature range from -40 °C
to +80 °C and the proTect+ impermeability concept which will retain IP69K
properties even after several temperature cycles. Another important application
is tailgate control at trucks.
Magnetic proximity switches ideally replace an inductive solution in similar tasks
where an extended sensing range is required. They
will respond to the magnetic field built by a permanent
magnet within a 60 mm distance and are impervious to
dirt and moisture).
Another
important
safety topic is load control,
and here’s where load cells
and load pins come into
play. They feature a wide
temperature range (-40 °C
to +85 °C) and IP67 protection. Thanks to default calibration they allow for eased
installation and are immediately ready to operate. They
directly communicate with
the vehicle or crane control
via their field-bus interface.
Positioning
Heavy vehicles and mobile facilities provide a tremendous variety of positioning applications. There
is always the optimally tailored sensor solution despite substantially differing
requirements: For example, absolute encoders with
CANopen interface are tried
and tested in water gun positioning at fire trucks. Ab-
Inclination sensors are a
kind of “electronic water
scale” to detect the inclination angle of vehicles, loading platforms or outriggers
in relation to the horizontal
plane.
54
Baumer sensors at fire trucks ensure the proper position of the water gun (encoder GXP5W with CANopen
interface), monitor the hydraulic system (pressure sensor
PBNM) and control the equipment compartment lock
(inductive sensor IFFM).
solute encoders with magnetic sensing are the product to choose for drill speed
and
feed
applications.
These encoders feature
CANopen and SAE J1939
interface as an option. Absolute multiturn encoders
(AMG 11) without gears and
battery provide redundant
output signals are optimally
suited for position feedback
at rope drums. Magnetic encoders of the HDmag platform eliminate the need for
mechanical bearings and
merge the benefits of noncontact and magnetic sensing technique with high resolution, top-grade accuracy and eased installation.
They are the optimum so-
lution for angle acquisition
straightforwardly at large
shafts. More typical applications are position and angle feedback at outriggers
or ladders. Where appropriate, magnetic angle sensors
may provide an efficient alternative approach.
Hall sensors are the
product to choose when it
comes to position detection at turntables. The sensors of the MHRM series
are shock- and vibration
proof and come in an ultra-resilient closed metal
housing. By virtue of their
two-channel output they
are ideal for gear applications and provide both rotating speed and direction of
Strain gage measuring amplifier
The GSV-3CAN measuring amplifier by MEMessysteme (Germany)
is suitable for networking
of sensors, such as force
sensors, strain sensors
and weighing. With this device the low analog voltages of strain gages are processed close to the sensor
and can be transferred via
the CAN network interference-free and in real-time
to the control room or the
data logger. Having dimensions of 64 mm x 58 mm x
34 mm in a aluminum die
cast housing (IP66-rated) the module features a
10-kHz sampling rate and
a 16-bit resolution. In particular, the adjustment capabilities make this measurement amplifier suitable for a broad range of
applications. The measured values can be ”compacted”, e.g., by selection
of FIR- and mean value filters. Individual value query and transfer with adjustable, continuous data
rate are just as possible
as external triggering or
the event-driven transfer
of measurement data.
(hz)
www.me-systeme.de
CAN Newsletter 3/2011
the gears. Another key factor in automated processes is presence checks, for
example at automated garbage trucks to make sure
the bin has been properly
loaded. Here, photoelectric
sensors take center stage.
They will detect most different objects independent of
their color within a 400 mm
sensing range. Photoelectric sensors have proved as
optimum solution by being
compact, shock-proof and
thanks to the proTect+ impermeability concept impervious to dust and moisture
(IP69K-protection).
Hydraulic systems
In many mobile applications, hydraulic pressure
is a basic parameter which
must be carefully controlled
and monitored. Pressure
sensors must provide special properties to match the
demanding requirements of
mobile deployment by specifically conceived techniques and materials. There
is a wide range of pressure
sensors: Fully-welded configurations of the PGNM
platform feature 0,1 % accuracy within the sensing
range. The total error sum
is inferior to 0,4 % throughout the entire compensated sensing range of - 40 °C
to +85 °C. Efficient, robust
and wear free sensors with
high switching sensitivity,
short response time and a
temperature range of - 10 °C
to +115 °C will prevent gears
or bearings from dry running. Inductive sensors are
ideally suited to detect positions of pistons inside hydraulic cylinders. Thanks to
different housings and optional M12 and M18 outlets
they provide most flexible
installation capabilities. In
stainless steel housing and
with a sensing face of zirconium oxide they defy even
the harshest environments
and easily withstand regular cleaning with aggressive
detergents.
www.baumer.com