Thursday, 17 August 2017

Industry response to Greg Clark’s plans to unlock smart energy


Last week, business and energy secretary Greg Clark revealed the government’s plans to make a £246m investment in battery technology over the next four years. Here, Nick Boughton, sales manager at industrial systems integrator, Boulting Technology responds to the announcement.

The plans, which have been released by the government and Ofgem, will look to give households and businesses more control over their use of electricity and break down barriers preventing new technologies from entering the energy market.

Here at Boulting Group, we welcome the decision to transform the way homes and businesses store and use energy.

The National Grid delivers electricity to millions of people, businesses and communities across the country, however its role is changing. Although the nation has traditionally relied on large fossil fuel and nuclear power stations to supply electricity, many of these larger power stations are now being closed down. As a result, the supply mix has to evolve.

At present, over a quarter of the UK’s electricity is being generated by renewable sources such as wind and solar energy. However, one of the concerns with this method is that production is often at its highest when demand is lowest. This makes storage for energy generated this way a key priority to eliminate waste and harness its true production potential.

Using batteries to store renewable energy is by no means a new concept. However, batteries for this purpose are often big, expensive and have a limited lifespan. In these newly proposed plans, the government has committed to removing barriers to the introduction of new technology into the power network.

Continued advancements in battery power, including decreased costs, are vital for this form of energy storage being rolled out on a mass scale.

Over the coming months, we will be working alongside our clients and partners to explore the potential of battery technology in the industrial sector. Looking only a few years ahead, we envisage efficient battery storage being commonplace across industrial sites, office blocks and homes.

We look forward to seeing how the government and Ofgem’s plans unfold. 

Tuesday, 4 July 2017

Preventative maintenance for MCCs

Preventative maintenance prolongs motor control centre lifespan

The Beverly Clock has not been manually wound in more than 150 years, but its clever mechanism keeps it ticking with minimal problems.  In spite of this, the clock has stopped working on a number of occasions. However by cleaning, maintenance and environmental changes the clock has been kept in operation.  To keep a Motor Control Centre (MCC) running, it’s important that maintenance is done proactively to prevent costly downtime. Here, Pat McLaughlin, operations director of Boulting Technology, explains why preventative maintenance is so important for MCCs.

MCCs are often at the heart of a manufacturing plant, providing power for equipment across the site. However, their important role often goes unrecognised - for a long time there has been a ‘buy and forget’ attitude to MCCs. It is a common belief that once an MCC is installed, it can be left to run independently and maintenance is only needed in the case of a breakdown.

The problem with this approach is that an MCC fault, such as a starter failure, can lead to major downtime by causing loss of power to, or control of, plant equipment. The consequences of interruption to production can mean significant financial losses to a business. Even worse, if documentation is not kept up to date or spare parts are missing, there can be a considerable delay getting processes back up and running.

If the MCC is neglected for an extensive period of time, this can lead to a risk of catastrophic failure, which leaves companies not only with downtime, but also with a hefty investment to replace the equipment.

Life expectancy
When purchasing a new MCC, the manufacturer will specify the life expectancy, or expected obsolescence, of the equipment. All MCCs have a finite lifetime, but not all of them meet initial expectations. Typically the life expectancy is around 20 years, but in some of the worst cases where components have failed in less than two years; this is usually when a fundamental lack of maintenance and other significant factors such as a very harsh environment has dramatically reduced its life. Preventative maintenance is a key tool to ensure that the MCC’s life expectancy is upheld.

In order to prolong the life of the MCC and limit the risk of breakdown, companies can enforce a Planned Preventative Maintenance (PPM) regime that involves proactive maintenance activities typically every three to six months. Incorporating a structured maintenance regime means that potential issues can be corrected before major downtime and ensures regulatory compliance.

Regulatory compliance
If an MCC is produced in Europe, it will be manufactured in accordance with EN61439 — the standard that defines specific requirements for switchgear and control gear assemblies. If it is later modified, there is a risk that the MCC may no longer comply with this standard. When maintenance involves replacing or changing components, companies need to be mindful of the regulations. Maintenance staff should check for any modifications, and ensure that documentation is up to date.

A new MCC will come with an Operation and Maintenance (O&M) manual with clear instructions on what procedures should be put in place and how to keep the MCC healthy and in-line with regulations. Companies can use this to plan preventative maintenance, ensuring that all important components are checked.

Assessing the situation
To find out the condition of the MCC, maintenance staff can conduct several checks. These can be intrusive or non-intrusive, from simple visual checks to more complex analysis.

It is important to make checks to establish the cleanliness, verify any software and check and backup the parameters on programmable devices. These parameters need to be up-to-date with records. Maintenance staff can make visual checks to look for any discolouration or burnt out equipment.

As MCCs are often tucked away, there is also a danger that vermin can be present. This can cause serious problems with cables or connectors becoming damaged or even destroyed. Maintenance staff should conduct regular checks on the physical condition of cabling. If problems are identified, steps can be taken to restore the MCC to a good condition. If problems are recurring, it is important to remove the root cause.

Restoring the MCC to how it should be is similar to taking a car in for a service.
Common maintenance activity includes cleaning and tidying equipment, cleaning air filtration systems and fans to reduce overheating and replacing the batteries of backup systems.

When a breakdown happens, it is common for maintenance to use a quick fix to get production going as quickly as possible. If previous maintenance has been done for a quick fix, this needs to be resolved by restoring everything to the manufacturer’s specification.

The aim of this maintenance is to restore the MCC to its original condition. If any components show wear and tear, these can be serviced or replaced. If there is a problem with the MCC, companies can then perform the required maintenance.

Health and Safety
MCCs generally present very few health and safety hazards, except when performing maintenance activities. It is vital that companies and their employees are aware of the hazards and take sufficient precautions to manage them. Before working on MCCs, maintenance staff should test the equipment to see if it is ‘dead’, follow correct procedures in the O&M manual and wear correct personal protective equipment (PPE). A risk assessment and method statement should be produced for each maintenance activity.

Intelligent devices
Smart controls on the MCC can be incorporated into preventative maintenance regimes by logging, informing and indicating the operator of important information. The operator can interpret this information to gauge how well the rest of the plant is performing, allowing for predictive maintenance across the rest of the facility. Therefore an intelligent MCC can be used to flag up instantaneous problems in other parts of the plant, for example if a fan motor is pulling an unusually high current. This allows the operator to investigate and correct the problem before it leads to a larger failure. 

Intelligent systems can also store data over a number of days or weeks, meaning trends can be formed and any abnormalities identified well before they cause an issue. This allows more focused PPM regimes to be adopted. It also allows for feedback of results of maintenance activities in that trends should return to normal once they have been completed.

Planned, periodic inspections, simple visual checks and an up-to-date record of all maintenance and modifications are imperative for MCCs. To take things a step further, companies can use intelligent devices to predict where maintenance is required elsewhere in the plant. Proactive maintenance is key to MCCs meeting the manufacturer’s life expectancy. By ironing out any faults MCCs can run just like the Beverly Clock, which keeps on ticking.

Thursday, 1 June 2017

Time to say goodbye?

When to replace your old motor control centre

A motor control centre (MCC) sits at the heart of an industrial plant. If well maintained, an MCC can last for decades, but despite their sturdiness, even the most reliable MCCs have to be retired at some point. Here, Pat McLaughlin, operations director of Boulting Group, explains the early warning signs that an MCC needs replacing.

There are several reasons for replacing an MCC, but the most common ones include obsolescence, incompatibility with new legislation or the condition of the MCC deteriorating. Technological advancements that allow the design of intelligent, more efficient MCCs are another reason why companies sometimes opt for an upgrade.

Many engineers will wait until an MCC breaks down completely before commissioning a replacement, but best practice dictates that through proactive maintenance and regular checks, plant managers and maintenance engineers can identify the early warning signs of a failure and better plan for the upgrade.

The potential defects discussed below are what maintenance engineers should look for when performing regular MCC checks. These audits should take place at least twice a year and log faults so that the information can be used retrospectively to better understand the condition of an MCC and predict potential risks.

Mechanical defects
A motor control centre has several electro mechanical components that are particularly susceptible to failure. These include the filters and fans, which need to be cleaned and checked regularly because they provide adequate air ventilation within the MCC. Poor ventilation can easily lead to overheating and the failure of critical components.

Visual checks should also cover whether the relevant warning labels are in place before performing maintenance on an MCC, so that maintenance engineers are not put in any danger during these audits.

Electrical faults
Maintenance engineers can employ several methods to check electrical equipment. These vary from simple visual checks that identify discoloured or burned out components, to more complex investigations using an infrared camera to analyse electrical equipment or bus bars and to highlight hot spots.

Engineers should also pay particular attention to the cables and connectors of the MCC, as these tend to degrade relatively quickly. Checks should also cover the running currents and shielding of the MCC, to ensure employees cannot access live components.

Health and safety
MCCs, particularly ones that have been in operation for a long time, can become health and safety hazards. Engineers were not as safety conscious back in the 80s or 90s as they are today, so there is a good chance that any MCC that is a couple of decades old could be revisited to ensure it doesn’t pose any health and safety risks.

For example, Boulting Group engineers recently helped a utilities company replace an MCC that had been in operation for 43 years. Because of its age, the condition of the MCC had deteriorated resulting in some component failure and potentially live and, possibly dangerous to maintenance staff.

Regulatory compliance
The well-known BS EN 61439-2 standard, which came into play on November 1, 2014, states that the enclosure of an MCC should fit the “type and degree of protection suitable for the intended application.” Best practice dictates that the enclosure should provide protection for equipment against external influences from any accessible direction and against direct contact, meaning that an ingress protection of at least IP2X is required. Older MCCs may not have been built to this standard, so it’s important to check that your equipment is compatible with the latest regulations.

Another critical design verification introduced by BS EN 61439-2 refers to the temperature rise limits of motor control centres. Temperature rise is essential to the reliability and long service capability of an MCC, because excessive temperatures result in the premature ageing and failure of components and insulation. The introduction of the new standard means that manufacturers must verify that each circuit within the assembly can individually carry its rated current.

If you are considering purchasing a new MCC, it’s important to make sure that it complies with BS EN 61439. This is the responsibility of the MCC manufacturer, but the client should also be aware of the requirements and the benefits of the new standard.

Environmental factors
Because MCCs often operate in demanding environments, there are certain environmental factors that can affect the equipment and shorten its operational life. Such factors include dust, moisture and steam, all of which can be very corrosive and damage bus bars or electrical equipment. Similarly, because MCCs are often tucked away in the depths of a building, there is the danger of vermin damaging cables.

Maintenance engineers need to be aware of these potentially harmful environmental forces and perform the relevant checks periodically. Although some of these variables — such as moisture or dust — can’t be eliminated, they can be mitigated and engineers can monitor sensitive components more closely.

New tech
More often than ever, companies are deciding to change or upgrade their MCCs to take advantage of the benefits that new technologies offer. One common upgrade involves replacing conventional starters with variable speed drives (VSDs) and adapting the MCC to accommodate this change. Since a VSD can reduce the energy consumption of a motor by as much as 60 per cent, this type of upgrade helps companies make significant energy and cost savings in the long term.

Intelligent MCCs also feature remote controls and better data collection capabilities, which can be used for condition monitoring and preventative maintenance. In turn, this reduces maintenance and breakdown costs in the long run and helps companies minimise overall operational costs and enhance productivity.


Regardless of the age of your motor control centre, preventative maintenance is the key to making sure it performs well for longer. After all, you wouldn’t skip an MOT on your car, so why would you pay any less attention to the motor control centre that lies at the heart of your industrial plant?

Wednesday, 10 May 2017

The future of electricity

In the UK, the majority of electricity comes from large, centralised power plants. Although this approach enables economies of scale in the energy sector, it means that customers, particularly those within inner cities depend on long-distance transmission to receive power. Here Nick Boughton, sales manager at industrial systems integrator, Boulting Technology discusses how businesses need to adapt to keep up with increased energy demands.

In a bid to reduce energy costs and improve reliability, customers are turning to local energy generation — power that is generated in underutilised spaces such as rooftops, landfills and empty car parks.

Local energy generation reduces costs and improves the overall efficiency of the power system. It minimises line losses and extends the lifespan of existing transmission infrastructure by minimising wear from overuse. It also creates a stronger, more resilient network of power in the face of extreme weather, human error and outsider attacks.

The benefits of local energy generation are clear for home owners, but commercial and industrial properties are also starting to explore the alternatives to the national grid.

The microgrid is a localised group of electricity sources and loads that normally operate as part of the national grid, but can disconnect and function autonomously if necessary.

These types of grids are maturing quickly within the commercial and industrial sectors in North America and Asia Pacific, but lack of standards limit them on a global scale. Having these standards in place would mean that manufacturers could access a more secure supply, avoiding regular power interruptions that can cause high revenue losses and long periods of downtime.

Renewables
Renewable sources currently produce more than 20 per cent of the UK's electricity and targets set by the European Union mean that this is likely to rise to 30 per cent by 2020.

Countries in Europe are building increasing amounts of renewable capacity in order to reduce their carbon emissions and boost supply security. Last year, Denmark’s wind farms supplied 140 per cent of the country's demand and Germany received all of its power from renewable energy sources for an entire day. While these were planned events, in May 2016, the UK hit the headlines as it had no coal-fired power stations meeting electricity demand for a short space of time as a result of the partial failure of a power import cable. It is events like this that highlight the eventual need for a more long-term market supply.

In 2017, the Scottish government bid to cut total climate emissions by 66 per cent within 15 years. This is one of the world's most ambitious climate strategies and is expected to cost up to £3 billion per year to implement. To cut emissions, the Scottish government has released a renewable energy programme, which includes targets of 40 per cent of all new cars sold in Scotland to be ultra-low emission and 80 per cent of Scotland's homes to be heated using low-carbon technologies.

Currently, solar energy is limited to daylight hours and wind power cannot be harvested all year round. The only way to guarantee a 24-hour renewable supply is to have a method of storage.


Leveraging car and mobile phone developments, modern battery storage systems will soon be used to store renewable energy. In just a few years' time, battery storage will be commonplace not just at grid level, but on industrial sites, office blocks and in the home too.

Tuesday, 4 April 2017

Intelligent switchboards of the future

Wunderland Kalkar, a children's theme park in Dusseldorf, Germany attracts over 300,000 people every year. The park has over 40 rides, a hotel and a restaurant on site, so it may come as a surprise that the attraction was once an unused nuclear power plant. Over time places and technologies have to change in order to keep up with user demand, especially in industry.

Here Nick Boughton, sales manager at industrial systems integrator, Boulting Technology discusses how switchboards need to adapt to keep up with increased energy demands.

The future of electricity
In the UK, the majority of electricity comes from large, centralised power plants. Although this approach enables economies of scale in the energy sector, it means that customers, particularly those within inner cities depend on long-distance transmission to receive power.

In a bid to reduce energy costs and improve reliability, customers are turning to local energy generation — power that is generated in underutilised spaces such as rooftops, landfills and empty car parks.

Local energy generation reduces costs and improves the overall efficiency of the power system. It minimises line losses and extends the lifespan of existing transmission infrastructure by minimising wear from overuse. It also creates a stronger, more resilient network of power in the face of extreme weather, human error and outsider attacks.

The benefits of local energy generation are clear for home owners, but commercial and industrial properties are also starting to explore the alternatives to the national grid.

The microgrid is a localised group of electricity sources and loads that normally operate as part of the national grid, but can disconnect and function autonomously if necessary.

These types of grids are maturing quickly within the commercial and industrial sectors in North America and Asia Pacific, but lack of standards limit them on a global scale. Having these standards in place would mean that manufacturers could access a more secure supply, avoiding regular power interruptions that can cause high revenue losses and long periods of downtime.

Renewables
Renewable sources currently produce more than 20 per cent of the UK's electricity and targets set by the European Union mean that this is likely to rise to 30 per cent by 2020.

Countries in Europe are building increasing amounts of renewable capacity in order to reduce their carbon emissions and boost supply security. Last year, Denmark’s wind farms supplied 140 per cent of the country's demand and Germany received all of its power from renewable energy sources for an entire day. While these were planned events, in May 2016, the UK hit the headlines as it had no coal-fired power stations meeting electricity demand for a short space of time as a result of the partial failure of a power import cable. It is events like this that highlight the eventual need for a more long-term market supply.

In 2017, the Scottish government bid to cut total climate emissions by 66 per cent within 15 years. This is one of the world's most ambitious climate strategies and is expected to cost up to £3 billion per year to implement. To cut emissions, the Scottish government has released a renewable energy programme, which includes targets of 40 per cent of all new cars sold in Scotland to be ultra-low emission and 80 per cent of Scotland's homes to be heated using low-carbon technologies.

Currently, solar energy is limited to daylight hours and wind power cannot be harvested all year round. The only way to guarantee a 24-hour renewable supply is to have a method of storage.

Leveraging car and mobile phone developments, modern battery storage systems will soon be used to store renewable energy. In just a few years' time, battery storage will be commonplace not just at grid level, but on industrial sites, office blocks and in the home too.

Intelligent switchboards
Switchboards sit at the heart of an infrastructure and therefore need to be able to make intelligent decisions regarding where its power is coming from and going to. The majority of switchboards are capable of redirecting energy to several sources when prompted, but there are very few that allow plant or office managers to make the most of their electricity supply.

The rise of Industry 4.0 and the Industrial Internet of Things (IIoT) gives hope that facilities will soon be able to operate autonomously. Smart sensors, programmable logic controllers (PLCs) and distributed control systems (DCS) are already widely used in the industry — intelligent switchboards could be the next step.

An intelligent switchboard should be able to schedule power use, based on the previous operating times of each application. If it receives power from renewable sources, it could use these predictions to supply energy back to the grid, keeping energy costs as low as possible for the owner of the facility. Generally, electricity is cheaper when consumer demand is lowest, mainly during the night. If the facility had the ability to store energy, an intelligent switchboard could also use tariff predictions to make decisions on whether to receive energy from the grid, or wait until a lower tariff is available.

An intelligent switchboard would also complement the use of demand-side response — a system which financially rewards customers for shifting their electricity use at peak hours. Currently, demand-side response is managed by sending a signal to the customer when they need to take action. Intelligent switchboards pave the way for an automated response to this signal, which could include switching to stored energy during these peak hours.


One thing that many people don't know about Wunderland Kalkar is that it was never fully operational as a nuclear power plant. Construction began in 1972 but delays and fierce protests from locals caused the plant to close down before it was ever finished. Today, many plant and office managers are also resistant to change, particularly with energy infrastructure such as switchboards. However, investigating the benefits of a more intelligent system and making the change could save them a small fortune in reduced energy bills, better tariffs and lack of wasted energy.

Friday, 3 March 2017

Made to measure

Benefits of bespoke motor control centres (MCCs)

One of the cornerstone works of Renaissance art is the ceiling of the Sistine Chapel, which was commissioned by Pope Julius II and painted by Michelangelo between 1508 and 1512. The nature of the space required Michelangelo to paint from a unique system of platforms. In the five centuries since its completion, Michelangelo’s masterpiece has been surprisingly durable. Resilience and adapting to a space are two requirements that art and industry have in common, particularly in the case of electrical equipment.

Here, Pat McLaughlin, operations director of Boulting Technology discusses how a made to measure motor control centre (MCC) can benefit both commercial and industrial operations.

The MCC was introduced to the manufacturing industry in 1950; it was launched in the automotive industry, a sector which uses a large amount of electric motors. Over half a century later, not only are motor control centres still in use, but they are extremely common across industrial and commercial applications.

A motor control centre is an assembly of one or more enclosed sections in a metal cabinet containing motor control units with a common power bus. It can also include variable frequency drives, programmable logic controllers and metering and can act as the service entrance for the building’s electricity.

Why an MCC?
Power distribution in large commercial and industrial applications can be complex, but with the help of an MCC, organisations can simplify the process. The entire MCC can be powered through one cable as opposed to the more complex option of using individual cables for each motor.

MCCs are primarily used for low voltage three phase alternating current motors between 208 V and 600 V. The power distributed from these motors can be used in a variety of applications including heating, cooling, lighting or motor driven machinery.

The main purpose of a motor control centre is to protect valuable electrical equipment. Using an MCC with the wrong specification can lead to problems including damage to components that may ultimately result in downtime. For this reason, it is important to purchase the right MCC to safeguard the rest of the system. Before commissioning the MCC, the client should consider the amount of current the horizontal bus should take, the bussing material and the feeder cables to ensure that the motor control centre will be safe in the long term.

Possibly the most important factor to consider when purchasing an MCC is the space and environment that it will go into. The MCC acts like the heart of a building, but its location doesn’t always reflect its importance, with MCCs often being cramped into ill-suited spaces. If the location of the MCC isn’t considered early on, it can be tricky to get a standard, off the shelf MCC to meet the requirements of the remaining space. This is one of the major benefits of commissioning a bespoke MCC.

Fitting the space
A bespoke MCC is the best way to get around spatial restrictions. A company can specify its technical requirements including how many starters are necessary and the dimensions of the available space. The MCC manufacturer can then create and discuss a proposal that is suitable for the company’s needs.

Bespoke MCCs designed and built by Boulting Technology can fit into almost any space through innovative L-shaped, U-shaped and back-to-back designs, that can reduce the overall footprint of the equipment. Boulting Technology offers genuine back-to-back designs that share both the main distribution bars and the risers. This differs from another common method of bespoke MCC manufacturing, where two linear lines are doubled back on themselves, thus doubling the depth. A genuine back-to-back MCC is more cost-effective as well as having half the footprint, which makes a genuine difference, especially when space is limited.

Electrical equipment design is a complex process and each production space has different requirements.  While back-to-back MCCs may be most suitable for some environments, a U-shaped MCC could work better for others. Only an experienced consultant will be able to provide an accurate recommendation of the best MCC design for the space at hand and process specific requirements.

Versatility
As well as meeting spatial requirements, bespoke MCCs can be designed to the exact technical demands of a company’s processes without being limited to the standard options given by the manufacturer. By working with an independent MCC specialist, companies can mix and match components from different manufacturers instead of having to go for a predesigned standard model. Using an independent vendor can speed up the process of creating a bespoke item as an MCC can be constructed with products the manufacture already has in stock, speeding up the build process by using an intelligent CAD package that is linked to the product directory.

One design feature that can make MCCs easier to maintain and replace is the option to have withdrawable starters. The benefits of this can be reaped in facilities that run numerous processes simultaneously, for example in water and waste water facilities or an oil or gas company. Recently, a utilities company commissioned a bespoke MCC for 16 starters for its pumps. The company required an MCC with a small footprint. A withdrawable MCC was the only type of equipment that could fulfil all these requirements simultaneously.


A bespoke MCC can also be designed so that it is suitable for the conditions of the space it will operate in. Some environments can be much harsher so components with higher ingress protection (IP) ratings may be required to safeguard the equipment from foreign bodies, humidity or other environmental factors.

Specifications
Although Boulting Technology’s bespoke MCCs meet the mandatory BS EN 61439 standard at all times, different industries may also have additional specifications. Liaising with an experienced engineer throughout the design and build stage can guarantee that the MCC meets all relevant industry standards.

An independent advisor can also assess whether existing MCC complies with all the relevant industry standards and regulations. Because MCCs have a long lifespan of around 25-30 years, the design of a bespoke MCC must be made to meet all future challenges. In the case of older MCCs, it is possible to replace or upgrade panels to meet new specifications, although commissioning a new one might often be a wiser decision but in an ideal situation, an MCC should be equipped for future challenges from the onset.

What are the downsides?
The perceived downsides of commissioning a bespoke MCC are that it is an expensive process with more work involved when connecting and disconnecting terminals. There is also concern about how long the bespoke MCC will take to manufacture. However,  bespoke MCCs can be made in six to ten weeks, depending on size. Boulting Technology boasts an impressive 25,000 square feet UK manufacturing facility and an experienced and knowledgeable workforce, capable of delivering bespoke MCCs in short time frames.

A further perceived downside of commissioning a new MCC is that may involve some element of downtime. However, in a recent project for a global chemicals producer, Boulting Technology limited downtime by keeping one half of the motor control centre live whilst the other half was replaced. The project took place over the bank holiday weekend to prevent the plant from shutting down during normal working hours.


In the last half a century, the MCC has been a crucial technology in simplifying power distribution. While an off-the-shelf motor control centre might be suitable for many applications, a bespoke MCC offers powerful benefits in a flexible footprint, better use of space and suitability for its environment. Just like Pope Julius II commissioned Michelangelo to undertake a unique project, purchasing a bespoke MCC may be the key to a resilient design, perfect for your space.

Wednesday, 7 December 2016

Top causes of PLC control system failure

Control system maintenance to minimise downtime 

On New Year’s Day 1968, the programmable logic controller (PLC) was first designed. Whilst most were busy celebrating and making resolutions, Dick Morley was planning his invention. The PLC has been used ever since to make logic based decisions in automated industrial processes. Despite their resilience and rugged design, PLC-based control systems can still break down and their failure can lead to costly downtime.

Here, James Davey, service manager of systems integrator Boulting Technology, discusses the top causes of PLC control system failure and how the risks can be minimised.

PLCs use microprocessors to digitally control industrial automated processes. Early PLCs replaced relay logic systems, but advancements over the years enabled them to cope with a larger number of inputs, processes and outputs. In essence, a PLC is a set of hardware and sequence of coded instructions that enables equipment to perform complex and reliable electromechanical functions.

A PLC will usually run constantly, despite the harsh industrial environment it operates in. Unfortunately, even this robust control system can fail sometimes, which leads to serious consequences, such as a production line or processes stopping altogether.

Downtime is extremely costly and, not only can it seriously affect plant output, with the recent advances in PLC technology that embrace safety-related functions, it can occasionally create a hazardous situation that needs immediate attention. To ensure this does not happen, businesses need to follow a planned maintenance routine.

When a PLC control system does break down, identifying the cause can be tricky. Often, a copy of the PLC software, a laptop, programming lead and a multimeter are the only tools necessary for diagnosing the fault, along with some knowledge of the processes. Sounds straightforward? In many cases it is, but the trap of complacency has a habit of biting. Below is a list of common reasons why PLC control systems fail.

I/O modules and field devices
About 80 per cent of PLC failures are a result of field devices, Input/Output (I/O) module failure or power supply issues. Typically, these defects manifest themselves as a sudden process stop or irregularity of performance. This is because the PLC control system is waiting for a signal to allow it to step through its program sequence. In this situation, the engineer usually determines where the sequence has stopped by interrogating the software ‘on-line’, with the aim of tracing the problem to a specific I/O module and input or output point.

By identifying the I/O point, the engineer can then trace the problem to its root cause. This could be a PLC configuration error, tripped circuit breaker, loose terminal block, failure of a 24 VDC supply or issues with wiring. It may be that the I/O module itself needs replacing. This relies on having a readily available supply of replacements, something that is becoming increasingly difficult for legacy systems.

Erratic behaviour or failures of groups of inputs indicate there is an internal PLC error or issue with a common power source. If the I/O module is not the reason for the failure and power and wiring issues have been eliminated, then attention should be paid to the field devices — the components external to the I/O module. These could be incorrectly configured, mechanically damaged or they could have failed electrically, for example due to water ingress.

Ground integrity
Proper grounding is important in protecting both the PLC and maintenance personnel. A well grounded enclosure can also act as a barrier to outside electrical noise. During maintenance or diagnosis, the engineer can perform a visual check of ground wiring to establish if there has been any damage or if there are any loose connections.

The engineer can test the integrity of the ground with a multimeter. By checking the resistance of the PLC ground terminal to a main earth bonding point in the equipment enclosure, we can establish if this is the root of the problem.

Power supply issues
The reliability of PLC-based control systems is dependent on having an uninterrupted power source. Power supply issues can result from a range of causes including loose or corroded cables and power supply failure.

In addition, many manufacturing facilities, utilities and infrastructure companies will usually have redundant power systems or install uninterruptable power supplies (UPS). This way, a part of the plant continues to function even in the event of a mains power failure, thus providing control of essential items in order to maintain its safe operation.

Even if an industrial plant considers a UPS nonessential and a complete process stop is manageable in the event of a power outage, a PLC’s memory can be lost when the power fails. This can lead to loss of process data, but also complete loss of operational programs. To prevent this, a PLC sometimes employs its own backup battery to ensure the device restarts correctly when power is restored.

Failure to maintain and replace the batteries in a PLC or UPS can lead to a major system failure in the event of a power outage.

It is vital to back up the PLC software regularly and store it securely. If an industrial plant fails to back up the system, it makes it incredibly difficult to resume normal function in the event of PLC memory loss. Furthermore, it turns a minor power loss incident into a major downtime issue.

Dealing with interference
Electromagnetic interference (EMI) and radio frequency interference (RFI) are common in industrial environments that contain a variety of electrical equipment. Anything from handheld radio transmitters used by maintenance staff, to a large motor starting can cause interference.

Companies need to control electrical noise as much as possible, because it can lead to intermittent faults or unusual behaviour and even PLC failure.

There are many ways to mitigate the risk of downtime caused by electrical noise through design. A Boulting Technology service engineer can recommend ways to minimise noise by relocating sensitive equipment, segregating systems with high power components and adding barriers, grounding, or shielding cable between sensitive equipment.

Network and communications
Most PLC control systems need to communicate with periphery devices such as Human Machine Interfaces (HMIs) and other ‘intelligent’ equipment. A typical communication medium will consist of an industrial network, which industrial plants increasingly base around industrial Ethernet. A loss of communication between devices will often result in immediate plant downtime.

Engineers can mitigate against communications failures by ensuring the physical network infrastructure is correctly installed and terminated, that network devices are suitable for purpose — especially when more and more devices are added — and firmware patches are regularly installed to maintain reliable and secure operation.

Heat
The environment is a critical factor in the life of equipment and control systems. Failure to service air filtration components in the control cabinet can cause insufficient airflow and cooling within the control panel. This can lead to equipment overheating and the acceleration of component failure.

Equipment will fail at high temperatures or humidity, particularly above the limits of maximum temperatures recommended by manufacturers. A high humidity can also lead to condensation forming on electrical components and, in turn, this can lead to failure. Industrial plants can mitigate by using panel-cooling systems or by considering where the control panel will be located during installation design.

Managing the risks
By following a simple best practice routine, companies can minimise the chance of PLC control system failure. Engineers should ensure the environment in which the control system operates is sound. Through systematic inspections, engineers can identify any overheating or electrical noise problems.

By regularly checking and testing batteries and UPS systems, companies ensure that in the event of a power fault, their system is reliable and operates continuously. Other maintenance activities include checking the wiring integrity, grounding, terminals, field devices, Ethernet and other industrial networks. Plant managers should regularly back-up software and install firmware patches.

Last, but not least, obsolescence management is also important because PLC manufacturers regularly cycle their product ranges. If you are operating with a component that is several years old, it is important to have a readily available replacement for it. Businesses can manage this internally or by using a third party, such as Boulting Technology, who is able to highlight the risks, indicate which areas of a control system are more likely to lead to failure and put a contingency plan in place to mitigate that risk, including sourcing legacy components.

Control system best practice is not all about the hardware. Regularly backing up PLC software ensures that if downtime does occur, normal function can resume quickly. Upgrading firmware also makes the system more secure because patches and upgrades eliminate known software vulnerabilities.

Although it has been around for a long time, the PLC is not invincible. However, with proactive maintenance, environment control and contingency plans, your PLC control system will be there to keep your operations up and running every day of the year, including New Year’s Day.