As with any type of programming, there is no one way to develop logic for an application or a process. This of course leads to the ability to make decisions that are based on the specific tasks or operations that need to occur. However, the flexibility of PLC programming environments provide ample opportunity to create a colossal mess.
At Turner Integrated Systems we adhere to specific guidelines for PLC programming practices. Not only has this proven to serve our customers well, but it has also been an asset to ensuring our team is consistent with each other allowing for simple diagnostics and clear understanding of modifications when changes need to be made.
In addition to simplifying future changes and troubleshooting, some of these best practices have drastically improved HMI and SCADA development times.
Top 5 Guidelines
Here are just a few of the main guidelines we follow:
On most modern PLC platforms, PLC tags are name-based and not just register-based addresses. This evolution has certainly made great improvements in interpreting logic and development efficiency, but it can get messy quickly without a proper naming convention for the tags. Aside from that, it can even lead to misdiagnosing logic issues if a tag is considered to be missing, but in reality it wasn’t named as expected.
On a basic level, tag names should begin with the device or process that the tag is associated with, followed by the function of the tag. This makes it simple when determining the full list of tags in play with a search for a device.
Also, many tag naming systems have a limit to the number of characters allowed. Even if a character limit didn’t exist, long tag names gets difficult to manage. This being the case, it’s a good idea to have well documented short-codes for functions. We use codes that have been around in the process control world for decades.
Device identification should also be as simple as possible. We use the device ID as found on the process and instrumentation diagram. For example, a run status input for Pump 1 should be titled P1.YI, P1/YI or P1_YI depending on the tag organization structure of the PLC in use. Along with each tag a description should be included in the tag properties that clearly explains the function of the tag.
UDTs or “User Defined Tags” is another tool that should be considered when developing PLC software. UDTs help group the key tags of a device or a logic function to allow for the building of tag templates.
This concept aids significantly in the assurance that tag names are consistent. When using UDTs an instance of the UDT can be created which automatically creates all of the related tags required for the device or process.
Logic Routine Structure
It is up to the programmer to decide the layout and scan order of logic routines. Our own guidelines require logic to have a basic organization that separates process related logic from device control logic.
Alarm logic is to be grouped depending on the type of alarm. Device related alarms should be in the logic area of the device. Process related alarms should be in the logic area of the process control logic. Miscellaneous alarms are to be in a separate routine.
As with any programming language, documentation in the form of commenting throughout the code is an expectation. Having the ability to read the intentions of a logic section helps to understand the importance of what the program is doing.
This not only helps with diagnostics, but it provides a clear path for understanding the best way to approach future modifications.
Change Management / Logging
Comments outside of the logic file in a dedicated change log is an important tool in understanding the evolution of a control system. When changes are requested, it’s not always understood what the complete effect of the change will be.
Some changes can involve ripping away logic that took hours to build. This is why it’s important to archive versions of a project file that can be tracked with a list of modifications that have been made. Some manufacturers provide software utilities to examine differences between logic files. These can be very useful but do not replace the need for a change tracking document.
These are just a few of the guidelines we have built into our workflow to guarantee our systems will perform as designed and allow our team to easily support our systems in the field for years down the road. This is not an exhaustive list, and we expect that as technology keeps moving forward with new logic control software and hardware solutions, our procedures will evolve along with them as necessary.
What Is SCADA Security?
SCADA security systems are put in place to protect Supervisory Control and Data Acquisition (SCADA) networks. These vital Industrial Control Systems (ICS) help to regulate a number of critical infrastructure services, including electric power, water, transportation, and natural gas. Protecting these systems from cyber attacks is an essential job.
Until recently, SCADA networks could only be monitored with traditional security methods—that is, employees needed to physically visit the station in which the SCADA system was located.
However, as computer technology developed, SCADA security systems improved as well. Wide Area Networks (WAN) allow various security components to easily communicate with each other, providing ongoing network security and monitoring.
Due to the fact that ICSs regulate a significant amount of critical infrastructure, they are frequent targets for cyber attacks. Although improvements in technology have improved SCADA security, an increase in the use of IP-based systems comes with its own security threats.
As organizations begin to provide more partners with access to the inner workings of their ICSs, it becomes easier for hackers to gain access to their systems. In fact, 40% of sites utilizing ICS have connections to public Internet, and over half of them don’t run up-to-date anti-virus software.
SCADA Network Security Threats
Cyber warfare continues to threaten network security every day. There are four main security threats that SCADA systems face:
- Hackers: These people may work as individuals or in groups. They gain access to SCADA networks with malicious intent, often for their own gain. They may also be employed by governments committing acts of cyber warfare.
- Employees: Workers often unintentionally cause problems within SCADA systems. Most frequently, these problems are accidental and can be remedied with additional training.
- Malware: Malware, including spyware and viruses, may not specifically target SCADA systems, but it can still pose a significant security threat.
- Terrorists: Unlike hackers, terrorists are generally not motivated by their own personal gain. Instead, terrorists specifically set out to cause a significant amount of damage to critical infrastructure.
Network Security Procedures
Completing thorough risk assessments and establishing security measures is vital to the safety of SCADA networks. One of the first steps to increase security is to document the entire system, taking note of the areas where it connects to any internal network or to the Internet. Documenting each person who has access to the SCADA system also helps increase security.
Once the network has been thoroughly mapped, it is important to create standard security measures to ensure the long-term safety of the system. Everyone who has access to the network should employ report monitoring, security checks, and regular risk assessments.
As security threats constantly evolve and adapt, network security must be assessed and necessary changes should be made on an ongoing basis. Some specific security measures that can improve SCADA security include:
- Disconnecting unnecessary SCADA connections and strengthening necessary ones
- Removing unnecessary services
- Avoiding reliance on proprietary protocols for protection
- Setting up 24-hour incident monitoring
- Establishing strong authentication procedures over any backdoors into the SCADA network
- Performing regular technical audits
Get Help to Secure Your SCADA Systems
SCADA systems can be challenging to secure—but at Turner Integrated Systems, our experts are up to the task. We create personalized turnkey ICSs that are secured for use in your unique application.
From the very beginning of the project, our engineers will work closely with you to ensure that we fulfill your needs. We drastically reduce security vulnerabilities by keeping all designing and manufacturing in-house—and we provide full installation and documentation services once the project is complete.
Industrial automation uses computerized robotic control systems to facilitate the use of manufacturing equipment with minimal human intervention. Unlike manual industrial processes, automation does not require manual human operation of each mechanical aspect of the manufacturing process.
Benefits of Industrial Automation
Automation has become the mainstay of industrial manufacturing due to its overwhelming cost efficiency and risk mitigation. Ongoing innovations and technological advancements have allowed manufacturers to upgrade their systems to increase product quality and overall productivity without the need for increased labor costs.
Industrial automation increases productivity, as the equipment can be programmed to run 24/7 at greater speeds than manually operated machinery. In addition, there is less worry about scheduling for holidays and weekends for an entire crew of employees. Production can continue apace without interruptions.
Since the parameters are programmed using computer software, there is less likelihood of costly mistakes due to human error. Automation further allows for more consistent and reliable product quality without the minute variations that commonly occur between workpieces in manual production.
Rather than having to adjust or install equipment for production shifts, automated systems can be configured to allow users to program changes with less manual intervention, facilitating faster and more reliable production adjustments.
Automated systems work in tandem with each part of the system, thereby reducing the risk of error between system components. In addition, computer software is pre-programmed for more accurate production.
Fewer workers will be needed on the line, and automated safety devices ensure that workers will spend less time in the vicinity of dangerous equipment as it operates.
Disadvantages of Industrial Automation
The only real disadvantage of industrial automation is the initial investment. While upfront costs may seem intimidating, they are easily offset by the energy and labor savings, enhanced production, and reduced energy use and material waste.
Types of Industrial Automation Systems
Industrial automation is used in a wide variety of manufacturing and fabrication industries. A variety of automation systems have been developed to suit the needs of different applications.
Fixed or Hard Automation
Fixed automation, or hard automation, is used for the performance of a simple and repetitive task. This method is ideal for high-volume production with little variation, as modifications to fixed automation equipment can be expensive and time-consuming.
Programmable automation is ideal for batch production, as the automated equipment may be reprogrammed or changed out for each new design. The process requires manual adjustment of machinery between batches.
Flexible or Soft Automation
Flexible automation, or soft automation, uses computer software to direct manufacturing equipment. The equipment used in flexible automation allows for production adjustment without equipment changes.
Integrated automation takes from all of the above technologies and combines them into one manufacturing system that is capable of both large-scale and batch production through the use of a computerized control system and a variety of versatile machines.
Industrial Automation Tools
Industrial automation relies on multiple internal tools. Below is a short list of the most common automation tools.
Programmable Logic Controller (PLC)
A PLC is an industrial computer control system used to manage automatic operations for pre-programmed manufacturing and industrial operations. This system constantly processes and analyzes information from sensors throughout the operation.
Supervisory Control and Data Acquisition (SCADA)
A SCADA system uses sensors and PLC systems throughout the manufacturing process to acquire and record data and events for analysis to enhance and improve system operations.
Human Machine Interface (HMI)
An HMI or Human Machine Interface is the user interface that connects an operator to the controller for an industrial system. The interface consists of hardware and software that allow user inputs to be translated as signals for machines that, in turn, provide the required result to the user. An HMI offers a visual representation of the operation of the machine providing real-time data.
Distributed Control System (DCS)
The DCS is the network that monitors and connects all of the devices and interfaces within the automated system.
Industrial Control Systems with Turner Integrated Systems
At Turner Integrated Systems, we are pleased to provide the highest quality industrial control systems in the industry. For more information on our automated industrial systems, contact us today!