Category Archives: Shift Register

BRX PLC Shifting Instructions

PLC shifting instructions will move bits in memory areas a fixed amount when instructed. Bits are on/off, 1 or 0 and are usually associated together to form a memory location. The memory location can be used for numbers or positions.
PLC BITS NUMBERS AND POSITION is a post that will review the different methods that the PLC will interpret the information in memory
We will be looking at the shifting (moving) of the bits within the memory location in several different ways. ROTL rotate left, ROTR rotate right, Math shift left operator, Math shift right operator, Math unsigned shift right operator and SR shift register are some of the instructions in our BRX PLC that will shift bits.
Let’s look at some samples of each of the above mentioned instructions. Continue Reading!

BRX PLC Math Instructions

Math instructions are used to perform mathematical calculations. The BRX PLC has math instructions that can be used in a wide variety of applications. We will be looking at the INC increment, DEC decrement, LERP linear Interpolation, RANDSEED Random Number Seed and the MATH Calculated Expression instructions. Your automation system that you implement may involve some or all of these instructions. As a system integrator you will require the use of these instructions in your commissioned programs.
Let’s get started with the BRX PLC Math Instructions. Continue Reading!

PLC Programming Example – Sorting Station (Shift Register)

We will apply the five steps to PLC program development to a sorting station example. The program will use shift registers to track coloured parts down a conveyor and sort depending on colour into one of three locations.

Developing the PLC program is a process that can be clearly defined. In our series on the five steps to PLC program development we have done some similar practical examples.
Five Steps to PLC Program Development
– Press
Process Mixer
Shift Register (Conveyor Reject)
Paint Spraying
Delay Starting of 7 Motors
– Pick and Place

Define the task: (1)
Watch the sequence of operation video below.
Watch on YouTube : PLC Programming Example – Sorting Station Testing
Continue Reading!

Omron CP1H Data Shifting Instructions

PLC programming is all about how we can manipulate the information stored in the PLC. We have already looked at timers, counters, moves and comparison instructions. Data shifting is a different concept that will move bits and words around in memory. This is necessary usually for tracking purposes. The word or bit will represent product or information. As this information is triggered to shift to a new location we can use this to activate items latter in the process. A typical example of this would be parts on a conveyor belt. As the part is detected on one end it will turn on a bit in a register. The conveyor movement is usually picked put by an encoder and shifts this bit in the register in sync with the conveyor movement. At the other end of the conveyor belt we can see the bit position and do something with this information. We can use this information to count, reject etc. Looking at the entire register full of bits, we can determine everything on the conveyor and its position.
We will be looking at the data shifting instructions in the Omron CP1H PLC. Examples of some of the instructions will be presented. The instructions are used to shift data within or between words, but in different amounts and directions. Continue Reading!

Horner XL4 Rotate and Shift Register

The Horner APG XL4 all in one controller has several different instructions to shift and rotate the bits, bytes, words or double words in the memory. We will be discussing the bitwise operations of the shift and rotate instructions. Looking further into the move operations we will look at the Element Rotate and Element Shift instructions as they pertain to a conveyor belt tracking application. Continue Reading!