PLC programs use discrete I/O handshaking that includes bits to turn the handshakes on or off based on the state of the rung.

PLC programs use discrete I/O handshaking that includes bits to turn the handshakes on or off based on the state of the rung.

• A. True
• B. False
• C. Not used
• D. Sometimes

Answer: (A)

Discrete I/O handshaking in PLCs is built around simple on/off boolean signals. Each rung’s state can energize or de-energize a coil that represents a handshake bit. When the rung condition is true, the handshake bit turns on, indicating a request or that another device can proceed. When the handshake has been acknowledged or completed, the logic can reset that bit, turning the handshake off. This mechanism keeps two or more devices synchronized by exchanging these on/off signals tied to the rung states. Therefore, it’s correct that PLC programs use discrete I/O handshaking that includes bits to turn the handshakes on or off based on the state of the rung. In practice you might see Set/Reset coils or latches used to hold the handshake until the other side responds.

Discrete I/O handshaking in PLCs is built around simple on/off boolean signals. Each rung’s state can energize or de-energize a coil that represents a handshake bit. When the rung condition is true, the handshake bit turns on, indicating a request or that another device can proceed. When the handshake has been acknowledged or completed, the logic can reset that bit, turning the handshake off. This mechanism keeps two or more devices synchronized by exchanging these on/off signals tied to the rung states. Therefore, it’s correct that PLC programs use discrete I/O handshaking that includes bits to turn the handshakes on or off based on the state of the rung. In practice you might see Set/Reset coils or latches used to hold the handshake until the other side responds.