Balluff BML-S1A-Q/A-M-0-S184/KA Serie Manual De Instrucciones página 33

BML-S1A_-Q/A_ _ _-M_ _ _-_0-S184/KA_ _
Linear Position Encoder
6 Selecting the Appropriate BML and Controller System
Tables 6 -1 and 6 -2 show the
relationship between the mech.
resolution, the min. edge separation
and the max. traverse speed for
BML systems using a magnetic
tape.
Important!
The controller/display must be able
to count the minimum time-based
edge separations shown in the
tables (note the counting frequency
of your controller). The min. edge
separation may even be present in
the stopped state due to the internal
interpolation procedure.
6.1 Standard BML (Tab. 6-1)
Selecting the appropriate BML
system for an existing controller
Example (see Table 6-1)
Assumptions:
– Your controller can detect a min.
edge separation of 0.5 µs. If
there is no BML with this min.
edge separation, select a BML
with greater edge separation.
– The max. traverse speed of the
system should be 1 m/s.
Determining the appropriate BML:
– You need a BML with min. edge
separation 1 µs (G-type).
- To be able to traverse at
max. 1 m/s, select the model
with 2 µm resolution (E-type)
Selecting the controller for an
existing BML system
What does the max. counting
frequency of the controller need to
be?
The period of the input signal is 4x
the edge separation (see Fig. 5-5).
The max. frequency of the input
signal is then 1/(4× edge
separation).
Example: With an edge separation
of 1 µs for the model G BML, the
max. frequency of the input signal is
1/4 µs = 250 kHz.
The max. counting frequency for
4x evaluation is 1/edge separation =
1/1 µs = 1 MHz.
With the standard BML the maximum traverse speed depends on the edge
separation and on the resolution (see Table 6-1).
In the table the X indicates the min. edge separation in time of the BML
model and Y the mechanical resolution (see part numbering code).
BML - S1A1 - Q61Y - M313 - X0 - KA05 (model example)
Standard BML
= 1 µm
D
Edge sep. X V corresponding to edge separation and resolution
max
= 0.12 µs
D 5 m/s
= 0,29 µs
E 2 m/s
= 0,48 µs
F 1 m/s
= 1 µs
G 0,65 m/s
= 2 µs
H 0,3 m/s
= 4 µs
K 0,15 m/s
= 8 µs
L 0,075 m/s
= 16 µs
N 0,039 m/s
= 24 µs
P 0,026 m/s
Table 6-1: Standard BML with defined min. edge separations
Edge separation
Mechanical resolution
Resolution Y:
= 2 µm = 5 µm
E F
10 m/s 20 m/s
4 m/s 10 m/s
2 m/s 5,41 m/s
1,3 m/s 2,95 m/s
0,6 m/s 1,54 m/s
0,3 m/s 0,79 m/s
0,15 m/s 0,34 m/s
0,079 m/s 0,19 m/s
0,052 m/s 0,13 m/s
english
= 10 µm
G
20 m/s
10 m/s
5,41 m/s
2,95 m/s
1,54 m/s
0,79 m/s
0,34 m/s
0,19 m/s
0,13 m/s
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