Mitsubishi Electric WS0-CPU0 Operating Manual page 217

Table 95:
Number of permissible
override cycles
Logic programming – Function blocks
During an override cycle, the Enable output is set to High as during a valid muting
sequence. The number of permissible override cycles is limited in order to prevent
excessive use of the override function. The number of permissible override cycles
depends on the value for the total muting time. Table 95 summarizes the number of
permissible override cycles:
Total muting time
5 s
10 s
20 s
30 s
1 min
5 min
15 min
30 min
60 min
Disabled (unlimited)
The number of override cycles is stored in the function block. The value is
incremented each time the Override required output starts pulsing or the Override
status output changes to high. The value is reset to "0", after a valid muting cycle has
occurred, after a system reset (e.g. using the Setting and Monitoring Tool) or after a
transition from the Stop state to the Run state.
After the Override required output has started pulsing at 2 Hz and a subsequent
Override signal has become High, Muting begins again and the Enable output
becomes High.
If the muting cycle is stopped because of a faulty input signal of a muting sensor,
Override required changes to High for the duration of the logic execution time,
provided that the remaining conditions for Override required are fulfilled. If the faulty
input of the muting sensor returns to High and subsequently to Low, the muting cycle
is stopped again and Override required becomes High, provided that the remaining
conditions for Override required are fulfilled.
During a valid override state, the direction detection, sequence monitoring (depending
on the function block) and concurrency monitoring are not carried out for the duration
of an override cycle.
Conveyor input
If the movement of the transported material is stopped during the muting cycle, the
total muting time and other parameters that can result in a muting error may be
exceeded. This can be avoided by using the Conveyor input. This input is used to
stop time-related functions connected with muting when the material to be transported
does not move further.
The Conveyor input has to fulfill EN 61131/IEC 61131 and has the following
properties:
0 V DC = conveyor belt stopped, e.g. Low
24 V DC = conveyor belt running, e.g. High
Number of permissible
override cycles
360
360
180
120
60
12
5
5
5
5
Remarks
Maximum number of override
cycles = 360
= 60 min/total muting time
Minimum number of override
cycles = 5
Chapter 9
214