How to Use Shift Register in Omron PLC

Shift Register in Omron PLC

In basic shift register is a register that is designed to allow the bits of its contents to be moved to left or right. Now when it come for a PLC to use such a register there are different instructions which make use of this instruction according the requirement. Like in Omron PLC the SFT(010) instruction can be used to shift a bit.


sft1.PNG

The bit will shift from Right to Left.

 sft2.PNG

When the execution condition on the shift input changes from OFF to ON, all the data from St to E is shifted to the left by one bit (from the rightmost bit to the leftmost bit), and the ON/OFF status of the data input is placed in the rightmost bit. sft3.PNG

The bit data shifted out of the shift register is discarded.
When the reset input turns ON, all bits in the shift register from the rightmost designated word (St) to the leftmost designated word (E) will be reset (i.e., set to 0). The reset input takes priority over other inputs.
St must be less than or equal to E, but even when St is set to greater than E an error will not occur and one word of data in St will be shifted.
When St and E are designated indirectly using index registers and the actual addresses in I/O memory are not within memory areas for data, an error will occur and the Error Flag will turn ON.
To learn how to implement the above instruction in PLC, follow the link below, here you will find step by step method to use this instruction.
https://www.youtube.com/watch?v=aOjQnwl6mww

2 Comments

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  2. There are 2 conveyor system controlled by 2 motors. Conveyor 1 is for product
    and conveyor 2 is designed for detection of empty box. When a start button is
    pressed, box conveyor will move. Once a box has been detected (using a sensor),
    the box conveyor will stop and the product conveyor will move and start to
    count for 7 products (using a sensor). At the end of conveyor 2, there is a sensor
    to detect the full box, so that the conveyor 2 will stop for 2 second and a solenoid
    is used to push the full box into a trolley. The system will run continuously until
    stop button is pressed......................................................how to solve the question using shift register ?

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