These days, ensuring high availability of industrial machinery control systems is a basic necessity. The fourth industrial revolution, or Industry 4.0, presents major challenges in manufacturing or service provision, including optimisation of operations, more flexible, more intelligent, more available systems.
What does the availability of a control system depends on and how is it measured?
We understand availability as the chance that a system will perform its job satisfactorily when it is needed. In other words, it is the proportion of time in which a system can perform its work without any failure.
It is stated with percentage values greater than 99.9%. Availability = MTBF / (MTBF+MTTR), where MTBF is the mean time between failures and MTTR is the mean time to repair.
This means that anything that limits this ability to perform its function will detract from this percentage. These failures can occur as a result of hardware, software and infrastructure failures. In addition, scheduled downtime to perform maintenance and/or system upgrades must be taken into account.
Example of availability calculation for industrial control systems
Let’s take as a reference the calculation over an annual period.
| Amount of nines | % of availability | Unavailability time | Time of
availability |
| 2 | 99% | 3 days 15horas 36min | 361 days 8hours 24min |
| 3 | 99.9% | 8 hours 45min | 364 days 16hours 15min |
| 4 | 99.99% | 52min 36sec | 364 days 23hours 7min 24sec |
| 5 | 99.999% | 5min 15sec | 364 days 23hours 53min 45sec |
| 6 | 99.9999% | 30 seconds | 364 days 23hours 59min 30sec |
Why does industry require high availability?
Industrial businesses mostly request a robust and secure infrastructure, with PLCs, backups, automations, SCADAs and all kinds of servers.
In fact, according to the Critical Infrastructure Protection Act (2011), it is essential for SCADA systems to have high availability, including, among others, change management and backup of automation assets such as PLCs, SCADAs and HMIs.
In other words, if your business has a complex and robust production system, you may well require high availability to optimise downtime and service interruptions.
According to a study by Price Waterhouse Cooper entitled “Opportunities and challenges of the industrial internet”: The basis of the fourth industrial revolution is the availability of all relevant information in real time, which is achieved by connecting all the elements involved in the value chain.
How to improve the availability of a control system?
There are essential points to ensure that the availability of a system is improved:
- Component redundancy. This is one of the best methods to increase availability in the event of a loss of visibility or a control shutdown. Component redundancy eliminates single points of failure, repairing, replacing or recovering from a failure without pausing operation.
- Network design. The network is a high availability system that needs to be managed at all times. This is why unplanned network outages represent another potential point of failure for high availability systems. For this, the creation of a redundant network strategy will be vital to avoid possible incidents.
- Diagnostics. Being able to diagnose control system elements will be the key to early detection of potential production failures.
- Virtualisation. Having operating systems and platforms that reduce the dependency of software on hardware when running will help to reduce restrictions over the life of the system.
- Hot swapping. Hot swapping is the only way to ensure high availability in a production line. That is, when any equipment needs to be replaced, it must be done without affecting the production process, restoring redundancy at that point.
- Online changes. To guarantee high availability, the systems must allow the addition, modification or improvement of the configuration of both hardware and software without stopping the installation.
- Predictive maintenance. Predictive maintenance is one of the techniques that can help companies in the industry to increase the availability of their equipment. Based on the application of Machine Learning technologies, it allows the anticipation of possible malfunctions of this equipment. In this way, action can be taken before they occur, minimising possible impacts on production.
Centralised platforms, a key element
Today’s high-performance companies depend on reliable access to tools, information and personnel to operate relentlessly and intelligently if they are to be competitive.
Nexus Integra integrated operations platform has been created to satisfy the most demanding availability needs in the market. Thanks to its structure, Nexus Integra allows you to monitor and control all your plants remotely and in real time. Obtain valuable information from the entire production chain and integrate data from the different departments in a transversal way.
Achieve high availability in your control systems with Nexus Integra, the platform that will help you to achieve a complete digital transformation.
Request a free consultancy with our specialised team.
