There are several considerations you need to make if your company is taking up PLC/SCADA development. While the two are closely related, you need to understand that they are separate entities.
Before you engage SCADA, you need to learn how to build programs on Programmable Logic Controllers(PLCs). Certainly, you want your project to be successful. Our goal is to help you get it right the first time. This article discusses critical factors you need to know as you begin PLC/SCADA development.
First of all, let’s debunk Programmable Logic Controllers(PLCs). Basically, these are components of Supervisory Control and Data Acquisition (SCADA). PLCs serve as microcomputers whose function is to record, process, and transmit measurements. They are mostly applied to local field environments since they are economical and capable of high transmission speeds at short distances.
By definition, SCADA is the system responsible for automating industrial processes through the integration of hardware and software controls. These systems exist on different scales—from manufacturing plants to home monitoring devices. SCADA systems are capable of collecting and processing system performance data in real-time and presenting the results on an operator interface.
The controller remains the foundational product for any automated system. For a reliable control platform, things such as functionality, cost, ease of programming, and maintenance should all be factored into decision making.
As you select a manufacturer, it’s also crucial that your controller can easily communicate with other devices integrated into your system.
Connectivity is another essential factor. If the system is designed to incorporate sophisticated peripherals such as highly specified sensors, choose a PLC family that has all the device type communications modules. Make sure to eliminate potential headaches by ensuring that your PLC of choice can support your Ethernet plug.
Making sure the manufacturer provides readily available support should also be one of your top priorities. Also, consider the type of support offered, does it address hardware or software? It’ll be both time-consuming and frustrating to later learn that your PLC vendor does not provide in-depth support promptly. While on the same note, examine the remote and local support provided.
You will need a PLC that has the processor power to handle all your intended functions. The worst thing that can happen is for your processes to lag whenever you try to run multiple operations. The ideal PLC should have ample memory and a fast processor. Be sure to check the PC load if high communication throughput is a vital part of the system. If you are to run at maximum cyclic load, then you will end up with inadequate capacity and response time that could jeopardize your operations. Ideally, the peak cyclic load should be below 65%, and static cyclic load below 60%, under all conditions.
Catering for your system’s future needs is just as important as those of today. When picking out a PLC, getting one that can handle more capabilities than your current needs is the right move. Stay a step ahead in case you need to add more capabilities in the future.
Work under the assumption that the system you are developing will be in place for quite some time. A long-standing solution will require a few modifications here and there. It is only reasonable to put in place a flexible system. This will keep the costs of changes low in the future. Note that you don’t need to do a full overhaul of the entire system to accommodate new functions. Instead, you can make amends to the existing system.
Building a reliable system requires quality components. Aside from the proper code needed to execute functions, you also need the PLC to provide a quality environment. Get your PCL from a reputable vendor, preferably one with lengthy warranties.
You can also opt for micro PLCs for more flexibility where possible. This more straightforward design can help you reduce the cost and time spent on designing your solution.
SCADA and PLC development are complex tasks that require diligence to provide the best product possible. The following are tips on how you can be cautious in some of the critical areas.
Bench tests are vital to your selection process. They will help you avoid any problems further up the development cycle. If you are exploring new waters, always bench test the controllers at your disposal. That way, you can be sure you are committing capable resources to the development process.
If you are assigning different developers to various parts of your PLC code, make sure everyone is on the same page. Merely sharing a diagram of the interfaces is not enough. Always make sure the interfaces are clear, and every team member will understand where the project is going.
PLCs offer several benefits for businesses. However, it’s essential not to overlook issues that could arise from their application. Maintaining a software configuration control document for the programmable function block parameters is vital. This approach makes it easier to conduct disaster recovery.
To make maintenance easier, your developers should make direct input on the structure of the system. Importing code that automates several machining functions without consulting your team will create problems if they ever need to fix a bug. Note that creating changes in the system is a common occurrence, and in the case of a change of equipment, your team may be ill-equipped to oversee a smooth transition.
The Human Machine Interface (HMI) provides the user of a SCADA system with graphical displays of data. Although it comes off as the last piece of the puzzle in the flow of data, it is wiser to start your project by programming the HMI first. Why? You may ask. In most cases, writing the program code first results in developers having to rewrite it to accommodate the HMI.
It’s also a good idea to rely on components you have prior experience with. Critical applications are less likely to malfunction if you use controllers you are familiar with and leverage a controller with the same revision level components, firmware, and software. Using hardware and software your team has previously been exposed to gives you the upper hand.
Leveraging a single control platform has many benefits for the development team—even more than customizing your controller selection for each application. You can compile your automation requirements including motion, robotics, sequence control, and the likes. Pick a control platform that corresponds to all your system needs. This move will result in unified programming methods across all devices and make maintenance easier to carry out.
It would be best if you didn’t turn a blind eye towards the fact that SCADA systems also have vulnerabilities. These security issues should be thoroughly addressed during development. To fortify SCADA networks from cyber threats measures such as mapping tools can be helpful in prevention. You need to make sure your operating system is secure by utilizing up to date protocols. Authentication is necessary, and incorporating authorization and login controls will also go a long way. Install measures that make it hard for hackers and malicious malware such as work to penetrate the system. The majority of SCADA systems automate functions through the internet. Unfortunately, this opens the system up to exploitation.
It will take less time to develop the right solution when you understand what the system is intended for and how it is to be used. This information will be instrumental in helping you keep your program as simple as possible while offering optimum functionality. If the job can be done through advanced I/O control, don’t waste resources by opting for a PC based system. This will only result in more work and an unnecessary bulky order. With a clearer picture of how the system will be applied, you may find some changes that may be necessary to make the system optimized to do what it is needed for.
Set your team up for success in PLC/SCADA development by picking the best hardware and software for the job. Read and apply these tips and best practices as they can help shape your successful venture.