Selecting The Appropriate Bml And Controller System - Balluff BML-S1C0-Q53-M400-0-KA Serie Mode D'emploi

BML-S1C0-Q53_-M400-_0-KA_ _
Magnetic Linear Encoder System
5

Selecting the Appropriate BML and Controller System

Table 5 -1 shows the relationship
between the min. edge separation,
the resolution 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.
5.1 Determining the appropriate
BML system for an existing
controller (linear motion)
Example (see Table 5-1)
Assumptions:
– Your controller can detect a min.
edge separation of 60 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 2 m/s.
Determining the appropriate BML:
– You need a BML with min. edge
separation 100 µs (R-type).
– To be able to traverse at
max. 2 m/s, select the model
with 500 µm resolution (N-type).
For the BML the maximum traverse speed depends on the min. edge
separation and on the mechanical resolution (see Table 5-1).
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-S1C0-Q53L-M400-R0-KA05 (model example)
Resolution Y V corresponding to edge separation and resolution
max
= 100 µm
L
= 200 µm
M
= 500 µm
N
= 1000 µm
P
= 2000 µm
R
Table 5-1: Relationship between min. edge separation, mech. resolution and
max. traverse speed
5.2 Determining the appropriate
BML system for an existing
controller (linear motion)
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. 4-1).
The max. frequency of the input
signal is then 1/(4× edge
separation). At 4x interpolation the
max. counting frequency of the
controller is 1/edge separation.
Example: With an edge separation
of 10 µs for the model G BML,
the max. frequency of the input
signal is 1/(4x10 µs) = 25 kHz. The
max. counting frequency at 4x
interpolation = 1/10 µs = 100 kHz.
min. edge separation
mech. resolution Y (see table for code)
min. edge separation X:
= 10 µs
M
8 m/s
10 m/s
10 m/s
10 m/s
10 m/s
X (see table for code)
= 100 µs
R
0.9 m/s
1,8 m/s
4,2 m/s
8,8 m/s
10 m/s
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