Function And Characteristics; Characteristics; Function; Ssi Interface - Balluff BTL5-S1 M HB-FA F C-Serie Betriebsanleitung

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

Function and Characteristics

2.1

Characteristics

Micropulse 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
– 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
1 2
+Clk
t
t
v
+Data
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 stain-
less 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 constantly updated.
The magnet defines the measured posi-
tion on the waveguide. An internally
generated INIT pulse interacts with the
magnetic field of the magnet to gener-
21 .
ate a magnetostrictive torsional wave in
the waveguide which propagates at
ultrasonic speed.
The torsional wave arriving at the end of
the waveguide is absorbed in the damp-
ing zone. The wave arriving at the be-
ginning 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 interface.
This takes place with high precision and
repeatability within the measuring range
indicated as the nominal stroke length.
At the rod end is a damping zone,
within which no reliable signal is avail-
able, but which may be entered by the
magnet.
Clock sequence
3 4 23
MSB
➀
Out of
Range
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
Micropulse 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. The max. clock fre-
quency t depends on the cable length
➥ ➥ ➥ ➥ ➥ section 8 Technical Data on page 9.
For the purposes of error detection bit
21
2
message, ➥ ➥ ➥ ➥ ➥ Fig. 2-1 and
Fig. 2-2.
Sending of the position values is
finished within time t
with the falling edge of the last clock
pulse. After this time the BTL is ready
for the next data transmission.
24
t < t
t
v
t
t
m
m
LSB
The time t
the last clock impulse (bit 24 or bit 25
depending on the version).
Null point

SSI interface

is provided as an "Out of Range"
. It is started
m
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
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