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Chapter Two Sequence Programming
11
Volume I
Programming
A
A
B
C
END1
.
.
.
.
.
.
.
.
It belongs to the 2
nd
partition
of the 2
nd
level program
Fig. 2-5-3-1
A=1 performs the 1
st
level program when the 1
st
8ms is performed, then B=1. And therefore, the
2
nd
level program is performed, the A=1 is latched to the 2
nd
level program, and then the first partition
of the 2
nd
level program is completed.
A turns into 0 to perform the 1
st
level program when the 2
nd
8ms is performed, then B=0. And
therefore, the 2
nd
partition of the 2
nd
level program is performed; in this case, the state of the A is still
latched as the one last time. So, C=1.
In this way, the state both B and C are different.
2.6 Interlocking
In the sequence control, the interlocking is very important from the safety issue.
It is necessary to use the interlocking in the sequence control programming. Simultaneously,
the hard interlocking is used in the relay control circuit of the strong electric cabinet of the machine
tool sides. This is the reason that the interlocking is disabled when the hardware of the performance
sequence programming malfunctions, even if the interlocking is logically used in the sequence
program (software). And therefore, the interlocking can be ensured the safety for the user, and
prevent the machine tool from damaging in the strong electric cabinet of the machine sides.
