Chapter 5 Basic Instructions Symbol: MC N ： Level of the nested program structure N0~N31 MCR Explanation: 1. The instruction MCR is used to set the master control. When the instruction MC is executed, the instructions between MC and MCR are executed as usual. When the instruction MC is OFF, the actions of the instructions between MC and MCR are as follows. 2. The instruction MCR is used to reset the master control, and is placed at the end of the master control program. There should not be any contact instruction before MCR. 3. MC/MCR supports the nested program structure. There are at most 32 levels of nested program structures (N0~N31). Please refer to the example below.
5-9 Instruction code Operand Function MC/MCR N Setting/Resetting the master control Instruction type Description General-purpose timer The timer value is reset to zero. The coil and the contact are OFF. Timer used in the function block The timer value is reset to zero. The coil and the contact are OFF. Accumulative timer The coil is OFF. The timer value and the state of the contact remains the same. Counter The coil is OFF. The timer value and the state of the contact remains the same. Coils driven by OUT All coils are OFF. Devices driven by SET and RST The states of the devices remain the same. Applied instruction All applied instructions are not executed.
The FOR/NEXT loop is still repeated N times, but the actions of the instructions inside the FOR/NEXT loop follow those of the instructions between MC and MR.