Mitsubishi PLC programming basic principles - Solutions - Huaqiang Electronic Network

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1. The Mitsubishi plc ladder program must conform to the principle of sequential execution, that is, from left to right and from top to bottom. If the circuit that does not conform to the sequence execution cannot be directly programmed, the circuit cannot be directly programmed.

2. Each line of the Mitsubishi PLC ladder diagram starts from the left bus and the coil is connected to the far right. In the relay control schematic, the contacts of the relay can be placed on the right side of the coil, but in the ladder diagram the contacts are not allowed to be placed on the right side of the coil.

3. The Mitsubishi PLC coil cannot be directly connected to the left busbar, which means that the coil output must be conditional as a logical result. If necessary, an internal relay's break contact or internal special relay can be used.

4. The same numbered coil of Mitsubishi PLC is used twice in one program and is called double coil output. The double coil output is prone to misoperation, when the front output is invalid and only the last output is valid. However, the action of the output coil corresponding to the contact is determined based on the output state before the logic operation. Due to the M1 dual coil output, the M1 output changes with the last M1 output, Y1 varies with the first M1 coil, and Y2 varies with the second M1 output. Therefore, in general, double coil output should be avoided as much as possible.

5. The number of series and parallel contacts in the ladder of Mitsubishi PLC is not limited and can be used without limit.

6. The contacts of Mitsubishi PLC external input/output relays, internal relays, timers, counters, etc. can be reused. It is not necessary to use a complicated program structure to reduce the number of contacts used.

7. Two or more coils of Mitsubishi PLC can be output in parallel.