Chapter 9
223
Logic programming – Function blocks
Where …
L
1
= Minimum distance between the detection line of the ESPE and the detection
by A1, A2
L
2
= Distance between the two detection lines of the sensors (sensors
activated/sensors clear)
L
3
= Length of material in conveyor direction
L
4
= Maximum distance between C1 and the detection line of A1, A2
v = Velocity of the material (e.g. of the conveyor belt)
t = Set total muting time [s]
T
IN Light curtain
, T
IN Muting sensor
= Response time of the light curtain or the muting sensors
in the MELSEC-WS safety controller (See the Safety Controller User’s Manual.)
Material flow is only possible in one direction in this example.
In order to move material in both directions (i.e. bidirectionally), place the
intersection directly in the light beams of the ESPE (See also Section 9.10.9).
The sensor layout shown in this example is suitable for both through-beam
photoelectric switches and photoelectric reflex switches.
Avoid mutual interference of the sensors.
Increase the protection against manipulation and the safety level by using the
following configurable functions:
– concurrency monitoring
– monitoring of the total muting time
– muting end via ESPE
Information on wiring can be found in Section 9.10.3.
Sequence/timing diagram
The function block requires that a valid muting sequence takes place. Figure 207
shows an example of a valid muting sequence based on the basic parameter setting
for this function block. The optional input C1 is not contained in the sequence shown
below.
Note
Figure 207:
Valid muting sequence
using the configuration basic
setting (C1 input: without,
Override input: without,
Conveyor input: without)
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