Balluff BML-S Series, User Manual, Page: 43 / 130

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7
System selection (continued)
7.2 Additional parameters for rotative
applications
The BML linear encoder 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-S2B/E…
Resolution
Impulses/rotation with 4x evaluation
Ø exterior magnetic ring
31 mm 49 mm 72 mm 75.4 mm 122 mm
Number of poles
(with 5 mm pole width)
20 32 46 48 78
F 5 μm 20,000 32,000 46,000 48,000 78,000
G 10 μm 10,000 16,000 23,000 24,000 39,000
H 25 μm 4,000 6,400 9,200 9,600 15,600
K 50 μm 2,000 3,200 4,600 4,800 7,800
Tab. 7-3: BML-S2B/E…: selection aid for magnetic rings
BML-S1C…
Resolution
Impulses/rotation with 4x evaluation
Ø exterior magnetic ring
31 mm 49 mm 72 mm 75.4 mm 122 mm
Number of poles
(with 5 mm pole width)
20 32 46 48 78
L 100 μm 1,000 1600 2300 2400 3900
M 200 μm 500 800 1150 1200 1950
N
500 μm 200 320 460 480 780
P 1000 μm 100 160 230 240 390
R
2000 μm 50 80 115 120 195
Tab. 7-4: BML-S1C…: 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 [min
–1
] =
60 × max. movement speed [m/s]
π × magnetic ring diameter [m]
Maximum movement speed and minimum edge distance,
see Tab. 7-1 und Tab. 7-2 on page 16.
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
14.75 m/s 9087 5749 3913 3736 2309
10 m/s 6161 3898 2653 2533 1565
8.8 m/s 5422 3430 2334 2229 1378
8 m/s 4929 3118 2122 2026 1252
7.7 m/s 4744 3001 2042 1950 1205
6.5 m/s 4005 2533 1724 1646 1018
5 m/s 3080 1949 1326 1266 783
4.2 m/s 2588 1637 1114 1064 657
3.95 m/s 2434 1540 1048 1001 618
3.25 m/s 2002
1267
1)
862 823 509
3 m/s 1848 1169 796 760 470
1.8 m/s 1109 702 477 456 282
1.7 m/s 1047 663 451 431 266
1.5 m/s 924 585 398 380 235
0.95 m/s 585 370 252 241 149
0.9 m/s 554 351 239 228 141
0.75 m/s 462 292 199 190 117
0.65 m/s 400 253 172 165 102
0.395 m/s 243 154 105 100 62
0.375 m/s 231 146 99 95 59
0.26 m/s 160 101 69 66 41
0.195 m/s 120 76 52 49 31
0.13 m/s 80 51 34 33 20
1)
See example below
Tab. 7-5: Maximum speed of rotative magnetic tape (magnetic ring)
Example:
BML-S2B… sensor head with 5 µm (F) resolution and a
min. edge distance of 1 µs (G).
Tab. 7-1 on page 16 produces a max. movement speed of
3.25 m/s for this sensor head. With a magnetic ring
diameter of 49 mm = 0.049 m, a speed of 1267 rpm can
be achieved with this formula (the value can also be read in
Tab. 7-5 (column 49/row 3.25)). Taking into account the
recommendation to remain 10% below this, a speed of
1140 rpm should not be exceeded.
BML-S _ B/C/E0-Q _ _ _ -M4 _ _ - _ 0-KA _ _ /KA _ _-S284
Incremental Magnetic Linear Encoder
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