Function And Characteristics; Characteristics; Function; Ssi Interface - Balluff BTL5-S1 B-M Serie Notice D'utilisation

BTL5-S1_ _B-M_ _ _ _-HB/WB-FA_ _/F_ _-C
Linear Transducer - Rod Style
2

Function and Characteristics

2.1

Characteristics

Transducers feature:
– High data security: Output data are
checked for validity and plausibility
in the µC.
– Very high resolution, repeatability
and linearity
– Absolute output signal
– Measurement range monitoring
with "Out of Range" Bit 2
– Immunity to shock, vibration, and
contamination
Control-compatible measured
–
position in real-time
– Tough assembly
– Housing of stainless steel
– Wear- and maintenance-free mea-
suring principle
– Pressure rated to 600 bar
– Teflon cable
– Capability of connecting cable
guard systems
– Enclosure rating per IEC 60529:
Cable version IP 68
(type tested at 5 bar / 48 h)
IP69/K with connected cable guard
system
Clock sequence
Fig. 2-1: Pulse diagram, example with 24 bit coding
➀ only for resolution > 5 µm
Position of magnet:
1) out of the measurement range
2) within the measurement range
3) magnet not present
"Out of Range" Bit 2 21 will be set
after the occurence of the event.
0
Value of the output data 2 ... 2
1a) 0
1b) max. at end point + 10 mm
2) proportional to distance
3) 0
Technical data are valid within the
measurement range only, i.e. between
null and end point.
2.2

Function

The transducer contains a tubular
waveguide enclosed by an outer
stainless steel rod. A magnet attached
to the moving member of the machine
or to the cylinder piston is moved
over the rod and its position con-
stantly updated.
The magnet defines the measured
position on the waveguide. An inter-
nally generated INIT pulse interacts
21 .
with the magnetic field of the magnet
to generate a magnetostrictive tor-
sional wave in the waveguide which
propagates at ultrasonic speed.
The torsional wave arriving at the end
of the waveguide is absorbed in the
damping zone. The wave arriving at the
beginning of the waveguide creates an
electrical signal in the coil surrounding
the waveguide. The corresponding
value is output as synchronous serial
data (SSI) via the RS 485/422 inter-
face. This takes place with high preci-
sion and repeatability within the mea-
suring range indicated as the nominal
stroke length.
At the rod end is a damping zone,
within which no reliable signal is
available, but which may be entered
by the magnet.
Sampling rate f
A
➀
20
:
Fig. 2-2: Output data shown with "Out of Range" situation
The electrical connection between the
transducer, the processor/controller and
the power supply is via a cable.
Dimensions for installing the
transducer: ➥ ➥ ➥ ➥ ➥ Fig. 3-1
Dimensions for installing the magnet:
➥ ➥ ➥ ➥ ➥ Fig. 3-4
2.3
Depending on the BTL version, the SSI
interface uses 24 or 25 bits and the
position values are transmitted in Gray
or binary code. Transmission of the
position values is finished in time t
The max. clock frequency t depends
on the cable length ➥ ➥ ➥ ➥ ➥ section 8 Tech-
nical Data on page 9.
Bit 2
Range" message, ➥ ➥ ➥ ➥ ➥ Figs. 2-1 and 2-2.
The position values and data from the
BTL can be polled at any desired sam-
pling rate f
output synchronous with the sampling
rate in real-time. The maximum sam-
pling rate is a function of the working
stroke ➥ ➥ ➥ ➥ ➥ Section 8 Technical Data on
page 9. If this rate is exceeded, the
same data value will be output multiple
times, e.g. a new position value will be
available only for every second sam-
pling.
t < t
t
v
t
m
The time t
the last clock impulse (bit 24 or bit 25
depending on the version).
Null point

SSI interface

21
can be used as an "Out-of-
. They are obtained and
A
m
= 150 ns measured with 1 m
cable
= 31 µs independent of the
clock frequency
starts with the falling edge of
m
End point
➀
english
.
m
3