Mitsubishi PLC basic data structure - Solutions - Huaqiang Electronic Network

Photocoupler

1. Bit component
The FX series plc has four basic programming components. In order to distinguish between various programming components, they are assigned a special alphabetic symbol:
x: Input relay for physical signals directly input to the PLC.
Y: Output relay for direct output of physical signals from the PLC.
M (auxiliary relay) and S (status relay): Operation flags inside the PLC.
The various elements described above are referred to as "bit elements" and they have only two different states, ON and OFF, which can be represented by binary numbers l and 0, respectively.
2. Word component
Eight consecutive bits make up one byte (Byte), 16 consecutive bits make up one word (Word), and 32 consecutive bits form a double word (Double Word). The current and set values ​​of the timer and counter are signed words. The most significant bit (bit 15) is the sign bit, the sign bit of the positive number is 0, and the sign bit of the negative number is 1. The largest positive integer that can be represented by a signed word is 32767.