Balluff BML-S1F Series, Руководство пользователя, Страница: 44 / 130

18
6
Interface (continued)
6.2.3 Additional parameters for rotative
applications
The BML position measuring system enables precise
adjustment to the respective application with the rotative
magnetic tapes (magnetic rings).
Definition of impulses per rotation
The number of required impulses per rotation varies
depending on the application. It defines the resolution of
the sensor head and the magnetic ring diameter.
BML-S1F…
Resolution
Impulses/rotation with 4x evaluation
Outer Ø of magnetic ring
72 mm 75.4 mm 122 mm
Number of poles
(with 1 mm pole width)
228 238 384
D 1 μm 228,000 238,000 384,000
I 2 μm 114,000 119,000 192,000
F 5 μm 45,600 47,600 76,800
G 10 μm 22,800 23,800 38,400
Number of poles (with 2 mm pole width)
114 118 192
I
2 μm 114,000 118,000 192,000
S 4 μm 57,000 59,000 96,000
G 10 μm 22,800 23,600 38,400
I 20 μm 11,400 11,800 19,200
Tab. 6-3: BML-S1F…: selection aid for magnetic rings
Maximum speed
The BML system enables recording of rotative movements.
The speed and magnetic ring diameter determine the
speed of the ring on the sensor head.
The selection of the resolution and edge distance of the
sensor head determines the maximum movement speed
that the sensor can detect. This results in a maximum
speed in accordance with the following formula:
Max. speed [rpm] =
60 × max. movement speed [m/s]
π × magnetic ring diameter [m]
Maximum movement speed and minimum edge distance,
see Tab. 6-1 and Tab. 6-2 on page 17.
Recommendation:
max. speed 10 % less than the
detected speed value.
Max.
movement
speed
RPM
Outer diameter
31 mm 49 mm 72 mm 75.4 mm 122 mm
20 m/s 12322 7795 5305 5066 3131
10 m/s 6161 3898 2653 2533 1565
5 m/s 3080 1949 1326 1266 783
2 m/s 1232 780 531 507 313
1 m/s 616 390 265 253 156
Tab. 6-4: Maximum speed of rotative magnetic tape (magnetic ring)
Example:
BML-S1F…-M3 sensor head with 1 µm (D) resolution and
a min. edge distance of 0.12 µs (D).
Tab. 6-1 on page 17 produces a max. movement speed
of 5 m/s for this sensor head. With a magnetic ring
diameter of 49 mm = 0.049 m, a speed of 1949 rpm can
be achieved acc. to the formula (the value can also be read
in Tab. 6-4 (column 49 mm/line 5)). Taking into account the
recommendation to remain 10% below this, a speed of
1754 rpm should not be exceeded.
6.3 Circuitry for reference position
Depending on the type, the sensor transfers the following
signals:
– No reference signal
– Single, double, or fixed-periodic reference signal that is
magnetically coded in the magnetic tape
– A pole-periodic reference signal (period = 1 mm,
reference signal width = edge distance, Fig. 6-1). If
several reference signals must be transferred, an
external selection switch must be mounted at the
desired reference signal.
Fig. 6-6:
External selection
switch
Sensor head PLC
Reference signal
for the controller
Reference position circuitry
BML-S1F_-A/Q _ _ _ -M_ _ 0- _ 0-…
Incremental Magnetic Linear Encoder
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