Yaskawa YASNAC PC NC PLC Programming Manual - Manual (Page 22)

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YASNAC PCNC PLC Programming Manual Chapter 4: Sequence Control Method
Since the low-speed processing sequence program is executed in several sections, the status
of inputs will be changed during the execution of the program. Therefore, the inputs that are
used for the execution of the low-speed processing sequence program should be taken into the
internal relays at the start of the low-speed processing sequence program, and for the execu-
tion of the low-speed processing sequence program, the contacts of the relays where the inputs
have been received should be used as the input signals.
Fig. 4.4 Low-speed Processing Sequence Program
By creating the program in this manner, one cycle of the low-speed processing sequence pro-
gram can be executed under the same input signal status.
1. If the results of the high-speed processing sequence program are output to the low-speed
processing program, the same consideration must be given to the creation of the program.
2. The signals that should not be output until one cycle of the low-speed processing pro-
gram is executed should not be directly output to the PLC address used for external out-
puts. Such signals should first be input to the internal relays and they should be connected
to the external output addresses at the end of the low-speed processing sequence program.
Fig. 4.5 External Output Addresses
(3) Reading and Outputting the State
(a) Reading the input state
After execution of the 8-msec high-speed sequence program, the status of all inputs is
read into the PLC collectively.
At the beginning of the 8-msec intervals, the previous output status is output collec-
tively.