Rockwell Automation Allen-Bradley 140M, Руководство пользователя

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42 Rockwell Automation Publication 450L-UM001F-EN-P - March 2022
Chapter 4 Safety Function
This muting mode is considered when the size and position of the pallet load is
irregular, or the size of the pallet is much smaller than the width of the
conveyor. This mode can require more space than the two-sensor T-type with
enable signal muting mode.
Sensors two and three (closest to the light curtain) are mounted within
200 mm (7.87 in.) of the light curtain. This position makes it difficult for a
person to enter the dangerous zone undetected by preceding or following a
load system into the dangerous zone.
The distance between any two muting sensors must be greater than 250 mm
(9.84 in.) so that a person's leg cannot activate them simultaneously.
The distance between sensors MS1 and MS4 is such that a cylindrical object
with a diameter of 500 mm (19.68 in.) with its axis parallel to the protective
field cannot activate the muting function when moved in any point of the gate
at any speed up to 1.6 m/s (see IEC 62064).
The muting sensors MS1-MS4 detect the objects on pallets and not the pallet
itself. When this action is impractical, additional measures can be necessary to
deter people from entering the zone by sitting on the pallet.
Figure 23 - Timing Sequence for Four-Sensor Muting
Muting of the 450L-E safety light curtain is achieved only when muting sensors
MS1 and MS2 are activated within the specified time (t
sens
). The delay between
the sensors must be larger than t
sens
minimum. For a successful muting
sequence, all four sensors must be simultaneously activated for a certain time
period.
The muting condition stops when either sensor MS3 or MS4 is deactivated, or
the maximal muting time (t
Mute
) is exceeded (muting timeout). Since this
muting mode is bidirectional, the muting sensor sequence also functions in
reverse (such as MS4 =>MS1).
Table 13 shows the default time limits. These values can be adjusted by using
Connected Components Workbench software.
Table 13 - Four-sensor T-type Muting Default Time Limit Settings
Parameter Default Value
t
sens
4 s
t
sens
min
50 ms
t
Mute
5 minutes
t
mdo
20 s
t
espe
5 s
ESPE
Muting Sensor S1
Muting Sensor S2
Mute
t
sens
t
sens
t
espe
t
Mute
t
espe
Muting Sensor S3
Muting Sensor S4