Do you have any idea what a PLC is? If you hear this word for the first time, it refers to a programmable logic controller, which has quite an extensive use in the industrial sector. It has the ability to make any type of process fully automatic.
PLCs are not a new invention, they’ve been around for decades. Their technology is already mature, so the only more significant improvements happen to their speed and design. The goal is to make them as fast and as small as possible.
Many factories adopt this type of controllers to aid their process of production. They get input in numerous ways as PLCs can use various kinds of interface, which makes them more convenient to use than the standard software computers.
When a company decides to purchase a programmable logic controller, there should be a basic training in order to learn how to use it. There are numerous trainings online and plenty of them are on YouTube, such as Allen Bradley PLC training.
However, although these trainings are of high importance, it’s also very significant to know how to choose the right PLC for your needs. Let’s see which features are of vital importance when selecting one.
Hardware
Selecting the hardware means having the exact information on the number of inputs and outputs required by your application. You shouldn’t limit your choice just to your present needs; if you believe that you’ll need more inputs and outputs in the future, calculate those too.
Another thing to decide is whether they will be local or remote. The former are directly connected to the controller while the latter are placed at a remote location and are usually connected to the controller via cables. If you choose to go with the remote type, you should consider the method of communication of your PLC, as this is also a very important factor.
Communication method
PLCs should be able to control all the operations of a machine and this can be done only if the controller and the machine communicate in an effective way. The controller can be directly or remotely connected. Most of the factories choose a remote way of connection, which in the past was done by using plenty of cables and wires.
Nowadays, there is something called the Ethernet, which helps in creating a local network area in which the machine and the PLC communicate. Ethernet is convenient and cheap to purchase, so make sure your controller has an Ethernet port, as you’ll most likely use this option. Visit this page for more information on the benefits of industrial Ethernet.
Control processing unit
The control processing unit is perhaps the most significant element which you need to carefully choose. This element provides the speed and memory of the controller. Good speed is essential for performing all the tasks in a timely manner, as usually the PLC would have to perform more than one task at a time. Vast memory is also needed in order to store all the information related to the machine operations.
If your application doesn’t require tracking of information over a longer period of time, then a controller with a solid data memory is suitable for you. However, if your application needs to keep track of certain values and measurements, you should look for a control processing unit with a program memory, capable of storing all the instructions given to the machine.
In case your application requires frequent scans and they need to be performed fast, then the CPU you choose should have a great speed of delivering the instructions.
Programming
Programming is extremely important if you want your PLC to understand and perform the instructions given to it by the machine. You need to determine whether your application requires some of the standard programming instructions such as timers, or perhaps specially designed instructions.
If you need a PLC with standard programming, you won’t make a mistake by choosing any type as most of them contain the regular traditional instructions. However, if the machine has to perform a specially designed task, then you need to look for a logic controller which supports this function. Read more about some of the most frequent PLC instructions on the following link: https://instrumentationforum.com/t/plc-instructions/4544.
You should choose a software which matches your current application needs, but also to be able to modify as technology changes in a very fast manner.
Longevity
The quality of the hardware is an important factor when it comes to the controller’s longevity. PLCs are famous for being accurate so its failure would be a disadvantage for the production process and for the whole company.
You should look for a hardware which can be fixed or replaced in case of a glitch and the cost of repair should be reasonable, not too expensive like purchasing a new hardware. Therefore, pay close attention to the warranty, given to you by the seller; it will tell you a lot about the quality of the controller.
Cost
Programmable logic controllers don’t cost plenty of money, especially if you compare their price to custom made software programs. Furthermore, they provide you with a high return on your investment, so they’ll pay off in a very short period.
However, when selecting one, make sure its price is not close to the price of the machine. For instance, if the machine costs 30, 000 dollars, don’t choose a controller worth 20,000 dollars. You can find perfectly suitable controllers for half of the price.
Wrap up
You have to consider a lot of factors prior to purchasing a programmable logic controller. Make sure it has the right hardware with a long lifespan. Choose the communication methods, the control processing unit and the programming carefully, if you want a smooth collaboration between the PLC and your machine.
Don’t go for the highest price.
Choosing the right type will not only ease your production process, but also improve your company’s reputation!