Mitsubishi PLC master control instructions - Solutions - Huaqiang Electronic Network

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The FX series plc has 20 or 27 basic logic instructions, 2 step instructions, and more than 100 function instructions (different series). This section takes FX2N as an example to introduce its basic logic instructions and stepping instructions and their applications.

FX2N has a total of 27 basic logic instructions, including 20 basic logic instructions of some sub-series PLCs.

Master command (MC/MCR): (1) MC (master command) is used for the connection of the common series contact. After MC is executed, the left busbar moves to the back of the MC contact. (2) MCR (master reset command) It is the reset command of the MC command, that is, the position of the original left bus is restored by the MCR command.

In programming, it often happens that multiple coils are controlled by one or a group of contacts at the same time. If the same contacts are serially connected in the control circuit of each coil, many memory cells will be occupied, and the master control commands will be used. This problem can be solved. The use of MC and MCR instructions uses MC N0 M100 to realize the left bus shift to the right, so that Y0 and Y1 are under the control of X0, where N0 represents the nesting level, and the number of uses of N0 in the no-nested structure is unlimited; MCR N0 returns to the original left bus state. If X0 is disconnected, the instruction between MC and MCR is skipped.

Instructions for use of MC and MCR instructions: (1) The target components of the MC and MCR commands are Y and M, but special auxiliary relays cannot be used. MC occupies 3 program steps, MCR occupies 2 program steps; (2) The main control contact is perpendicular to the general contact in the ladder diagram. The main control contact is a normally open contact connected to the left busbar and is the master switch that controls a group of circuits. The contacts connected to the main control contacts must be commanded with LD or LDI. (3) When the input contact of the MC command is turned off, the integrated timer, counter, and component driven by the reset/set command in MC and MCR remain in their previous states. For non-integrated timers and counters, components driven by the OUT instruction will be reset. When X0 is turned off, Y0 and Y1 are turned OFF. (4) If you use the MC instruction again in an MC instruction area, it is called nesting. The number of nesting levels is up to 8 levels, and the number is increased in the order of N0→N1→N2→N3→N4→N5→N6→N7. The return of each level is reset from the nested level with a large number by the corresponding MCR instruction.