Function And Characteristics; Characteristics; Function; Ssi Interface - Balluff BTL5-P-3800-2 Serie Manual De Uso

BTL5-S1_ _B-M_ _ _ _-P-(SA244)-S32/S147/KA_ _
Micropulse Linear Transducer in Profile Housing
2

Function and Characteristics

2.1

Characteristics

Micropulse transducers feature:
– Measured position can be used
for loop feedback (real-time)
– High data security: Output data
are checked for validity and plau-
sibility in the µC
– Very high resolution, repeatability
and linearity
– Measurement range monitoring
with "Out of Range" Bit 2
– Immunity to shock, vibration, and
contamination
– An absolute output signal
– Wear- and maintenance-free
– BTL to processor cable lengths
up to 400 m
– IP 67 per IEC 60529
2.2

Function

The Micropulse transducer contains
a waveguide enclosed by an ex-
truded aluminum housing. A mag-
net attached to the moving mem-
ber of the machine is moved
across the top of the housing and
its position constantly updated.
Clock sequence
Fig. 2-1: Pulse diagram, example with 24 bit coding
➀ only by an resolution of > 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.
Value of the output data 2 0 ... 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.
The magnet defines the measured
position on the waveguide. An
internally generated INIT pulse
interacts with the magnetic field of
the magnet to generate a magneto-
strictive torsional 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 arriv-
ing at the beginning of the wave-
21
guide 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 interface. This
takes place with high precision
and repeatability within the mea-
suring range indicated as the
nominal stroke length.
On both ends of the nominal
stroke length is an area which pro-
vides an unreliable signal, but
which may be entered.
The electrical connection between
the transducer, the processor/con-
troller and the power supply is via a
cable, which is connected using a
female connector.
Sampling rate f
A
➀
Null point
1a
21
Bit 2
20 :
~10 mm
0 20
Bit 2 ... 2
Fig. 2-2: Output data shown with "Out of Range" situation
Dimensions for installing the
Micropulse transducer and for the
magnets and control arm are found
on ➥ ➥ ➥ ➥ ➥ page 5.
2.3
Depending on the BTL version, the
SSI interface uses 24 or 25 bits
and the position values are trans-
mitted in Gray or binary code.
Transmission of the position values
is finished in time t
clock frequency t depends on the
cable length ➥ ➥ ➥ ➥ ➥ section 8 Technical
Data on page 9.
Bit 2
Range" message, see Figs. 2-1
and 2-2.
The position values and data from
the BTL can be polled at any de-
sired sampling rate f
obtained and output synchronous
with the sampling rate in real-time.
The maximum sampling 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 ev-
ery second sampling.
t < t
t = 150 ns
v
t = 31 µs
m
The time tm starts with the falling edge of
the last clock impulse (bit 24 or bit 25
depending on the version).
3
2

SSI interface

. The max.
m
21 can be used as an "Out-of-
. They are
A
m
measured with 1 m cable
independent of the clock
frequency
End point
2 1b
~10 mm
english
3