Automatic floor display of four-story elevator shows ladder diagram - Database & Sql Blog Articles

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

Photocoupler

Left busbar

X1 is the top level limit switch. The MOV (Transfer Instruction) transfers the number 4 to the data register D0 when X1 is closed. X2 is the bottom limit switch. The MOV (Transfer Instruction) transfers the number 1 to the data register D0 when X2 is closed.

X0 is the speed change signal. When the speed change signal arrives, the elevator goes up one level, and the internal device auxiliary relay M106 of the plc is turned on for one scanning period. When the M106 is turned on once, the addition instruction INC automatically increases the data in D0 by one. The subtraction command DEC automatically decrements the data in D0 by one when the elevator goes down one level. When the auxiliary relay M5 is closed, it indicates the elevator ascending state, and when M6 is closed, it indicates the elevator descending state. The M8000 is a special auxiliary relay inside the Mitsubishi FX series PLC, which is normally open during RUN. (The discussion of M5M6 will be discussed later).

CMP is a comparison instruction. Compare K1 with the data in D0. When D0 is equal to 1, the auxiliary relay M201 operates.

M201 drives M101 action, and M101 drives drive output relay Y003 again. Indicates that the elevator is parked on the first floor. The remaining layers

The principle of action is the same. After the Y001Y002Y003 action, the BCD decoder is triggered, and the BCD drives the 7-segment LED to show that the elevator is on several floors.

This is a mature elevator control program that is worth learning and learning from elevator programmers.