Shift Register Ladder Diagram

PLC (Programmable Logic Controllers)
1

Reset (Rung 1)

  • Contact: Reset button (RB)
  • Coil: Shift Register Reset (SRR)

Load (Rung 2)

  • Contact: Load button (LB)

  • Coil: Shift Register Load (SRL)

Shift (Rung 3)

  • Contact: Shift button (SB)

  • Coil: Shift Register Shift (SRS)

Data (Rung 4)

  • Contact: Data input (DI)

  • Coil: Shift Register Data (SRD)

1726511042494

How it works?

Reset

When you push the reset button, the shift register is cleared.

Load

When press the load button loads data into shift register.

Shift

When the shift button is pressed, data in the shift register moves one bit to the right (or left).

Data

The data output coil receives the shift register’s data output.

Solved Example

Let’s say we wish to move a 4-bit binary number (1010) to the right by one bit. The following is how the ladder diagram should operate:

Reset: Clear the shift register (0000)

Load: Load the data input (1010) into the shift register

Shift: Shift the data one bit to the right (0101)

Data: The output data is now (0101)