Yaskawa YASNAC PC NC PLC Programming Manual - Manual (Page 80)

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YASNAC PCNC PLC Programming Manual Chapter 6: PLC Instructions
6.3.4 Control Instructions
The control instructions are described below.
(1) NOP (No Operation) RR after operation: RR-
(a) Function
No operation is executed and the program advances to the next step.
The content of RR remains unchanged before and after the execution of the instruction.
(b) Format
NOR
(2) MCR (Master Control) RR after operation: RR-
(a) Function
The instruction executes the sequence ladder program when the both X1 and X2 contacts
are ON (RR = 1).
If the X1 or/and X2 contacts are OFF (RR = 0), the ladder program is executed to END
in the state of “RR = 0”.
(b) Format
MCR
(c) Explanation
• It is possible to enter another MCR instruction between the MCR and END
instructions (max. 7 levels).
• When a timer instruction is included in the MCR instruction, the timer is cleared
when the MCR instruction is OFF.
• Even if the self-holding circuit is formed between the MCR and END instructions,
the circuit output is OFF when the MCR instruction is OFF.
• With the MCR instruction, the output coil state is not retained.