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This blog article analyses the technical requirements, selection criteria, and application limits of capacitor-based buffer modules using practical application examples.

Power outages pose a significant risk to the operational continuity of electrical systems. In Germany, the average unavailability of electrical energy, according to SAIDI (System Average Interruption Duration Index), is 12.2 minutes* per end consumer per year (as of 2022). In comparison, the corresponding value in the USA is 125.7 minutes**.

The causes of these interruptions are diverse and range from weather-related impacts, such as ice loads and lightning strikes, to technical faults in the transmission and distribution levels, and even to deliberate interventions in the grid structure in the form of sabotage or cyberattacks.

In industrial applications in particular, even brief voltage interruptions on the DC side can lead to significant disruptions: unplanned system shutdowns, data loss in programmable logic controllers (PLCs), timing errors in drive controllers, as well as thermal and mechanical stress caused by uncontrolled shutdowns of loads.

To protect critical DC consumers, uninterruptible power supplies (DC-UPS) and buffer modules are therefore used. These can generally be divided into two categories:

Capacitor-based buffer modules for short-term bridging in the millisecond range
Battery-based DC-UPS systems for longer buffering times ranging from
minutes to hours

This blog post is the first in a two-part series that explores the technical specifications, decision-making factors and operational boundaries of buffer modules through real-world application scenarios. In the follow-up article, we will take an in-depth look at DC-UPS solutions and their role in long-term power reliability.

“Even brief power interruptions in industrial DC systems can cause costly disruptions. PULS ensures reliability with capacitor-based modules for short-term buffering and DC-UPS systems for long-term resilience.”

Peter HuberSenior Application Engineer | Author of this blog article

Capacitor-based buffer modules: reliable bridging for millisecond-scale power interruptions

Very short-term power interruptions and voltage fluctuations—often lasting just milliseconds—can have a major impact on industrial systems. While standard industrial power supplies include an integrated hold-up capacitor that typically bridges outages for 25 to 50 milliseconds, this is not always sufficient for sensitive applications.

To extend buffering time, capacitor-based buffer modules with electrolytic capacitors offer an ideal solution. These modules are:

Optimized for bridging power interruptions up to 200 milliseconds under nominal load
Compact, maintenance-free and easy to install
Designed for wide temperature ranges and long service life (typically over 10 years)

The bridging time during a power outage is directly determined by the energy stored in the capacitor, which depends on the capacitor’s voltage and capacity. This energy (E) can be calculated using the formula:

Formula for calculating capacitor energy.

Where:

E = energy in joules (J)
C = capacitance in farads (F)
U = voltage in volts (V)

This equation is critical when designing capacitor-based buffer modules for industrial DC systems. To increase the stored energy, engineers can either raise the capacitance or the charging voltage. However, since voltage has a quadratic effect on energy (doubling the voltage quadruples the energy), PULS prioritises voltage optimisation during product development to maximise buffer performance.

Seamless transition after power interruptions

In addition to energy storage, the transition phase following a power outage is crucial. The upstream DC power supply must resume operation without delay or voltage dips. This makes the selection of a power supply unit with suitable startup behaviour a key design consideration when integrating buffer modules.

Visualising the bridging phase

A typical power interruption scenario involves two voltage curves:

The AC input voltage, which drops during an outage
The DC output voltage, which remains stable due to the buffer module

As soon as the DC output from the power supply drops below 22.5 V, the buffer module automatically takes over, maintaining a stable voltage to the connected load. Once the AC mains returns, the power supply resumes operation seamlessly—ensuring uninterrupted power delivery to critical DC consumers.

Image 1: Temporal progression of a bridging phase during a power outage using a buffer module.

Custom buffer voltage configuration for voltage-sensitive applications

PULS offers a unique feature in its UF series buffer modules: the ability to configure the minimum buffer voltage to precisely 1 V below the set output voltage. For example, if the power supply is set to deliver 28 V, the buffer module can be parameterised to activate at 27 V—rather than the standard threshold of 22.5 V.

This fine-tuned voltage adjustment is particularly beneficial for voltage-sensitive loads or systems with tight tolerance requirements, where even minor voltage drops can cause instability or data loss.

In standard operation, buffer modules only engage when the output voltage falls to 22.5 V. With this configurable feature, however, buffering begins earlier, ensuring a more stable and reliable DC power supply for critical components.

Controlled shutdown with capacitor-based buffer modules during extended power interruptions

Capacitor-based buffer modules are ideal for applications that require a limited bridging time to safely shut down systems following a DC power outage. These modules provide a short but critical time window to transition equipment into a defined, de-energised state—minimising the risk of data loss or hardware damage.

Early detection of voltage drops is essential for this strategy. Typically, this is achieved via the DC-OK signal at the output of the power supply. Once a drop is detected, the buffer module immediately takes over the load supply and maintains stable DC voltage until its stored energy is depleted.

Image 2: During extended power outages, buffer modules extend the buffer time to transfer the system to a safe state.

This controlled shutdown capability ensures a fault-free restart and protects sensitive components such as PLCs, industrial PCs, and automation controllers. It’s a key feature for maintaining operational integrity in industrial environments with unpredictable power conditions.

Note: If the actual load is below the maximum permissible output current of the buffer module, the available buffer time is extended accordingly. Therefore, a careful choice of the power supply considering the actual power consumption is crucial for the effectiveness of the shutdown strategy.

Capacitor buffer modules for targeted sub-branch protection

In industrial DC systems, capacitor-based buffer modules can be strategically deployed to protect sensitive sub-branches of the power supply. By integrating a redundancy module, the output side of the power supply is divided into buffered and unbuffered branches—optimising energy distribution based on load sensitivity.

Power-intensive consumers such as actuators are connected directly to the power supply and excluded from buffering. This ensures that the buffer energy is reserved for critical components like sensors, PLCs, industrial PCs, and control logic.

Image 3: By cleverly dividing into load branches, control functions can be buffered for a longer period time.

Buffer modules: By cleverly dividing into load branches, control functions can be buffered for a longer period time.

This targeted buffering approach significantly extends the available buffer time, often reaching into the seconds depending on system architecture. It enables reliable data retention, controlled shutdown sequences, and improved resilience for voltage-sensitive equipment.

Cascading capacitor-based buffer modules: Extend buffer time and boost peak current capacity

Capacitor-based buffer modules from the PULS UF series are engineered for seamless integration in industrial DC systems. These modules, equipped with electrolytic capacitors, function like electronic capacitors and can be connected in parallel—either at the power supply output or directly at the load.

By cascading multiple buffer modules, users can:

Extend buffer time during power interruptions
Increase peak current capability without oversizing the power supply
Optimise system design for dynamic load profiles

This modular approach offers several advantages:

Cost savings through the use of smaller, more efficient power supplies
Improved operational reliability during short-term load peaks
Flexible scalability by expanding buffer capacity as needed

Image 4: Parallel connection of UF series buffer modules to extend buffer time or increase peak current reserves.

Image 5: Coverage of peak currents through additional energy from the buffer module.

During high inrush current events—such as motor or conveyor system restarts—the buffer module supplements the power supply with additional current. This prevents overload conditions and ensures stable operation.

Buffer modules for power systems in intralogistics applications.

Practical example: Buffering in intralogistics systems

In conveyor systems used in intralogistics, goods are frequently stopped and restarted. These restarts generate brief but intense current spikes. By integrating a buffer module, engineers can select a smaller power supply optimised for continuous operation, while the buffer module handles the short-term peak loads.

Conclusion: Selecting the right buffer strategy for reliable DC power supply

This article focuses exclusively on capacitor-based buffer modules and their role in short-term DC power continuity. These modules offer fast response times, scalable energy storage, and targeted protection for sensitive components—making them ideal for bridging millisecond-level interruptions, managing dynamic load profiles, and enabling controlled shutdowns during extended outages.

For applications requiring longer bridging times – from several minutes to hours – DC-UPS systems with battery storage provide the necessary autonomy and flexibility. These systems are designed to maintain regulated output voltage, support critical infrastructure, and offer advanced features such as black start capability and intelligent battery management.

In our next article, we’ll explore DC-UPS solutions in detail, highlighting their technical advantages, configuration options, and use cases in environments where uninterrupted power is essential.

Which back-up solution works best for your application?

Speak directly with our experts – we support you in the selection, design-in and integration of the appropriate buffer solution.

* Source: Bundesnetzagentur | Data of 2022 https://www.bundesnetzagentur.de/SharedDocs/Pressemitteilungen/DE/2023/20231107_SAIDI.html

** Source: U.S. Energy Information Administration (EIA) | Data of 2022 https://www.eia.gov/electricity/annual/table.php?t=epa_11_04.html

MCB vs. eFuse: Which is the best solution for properly securing DC circuits?

Power Supply

Basics

System Availability

This blog article compares a traditional miniature circuit breaker (MCB) and an electronic circuit breaker (ECB) with integrated eFuses, highlighting the advantages of an ECB in terms of faster and more reliable tripping without the need for peak current.

In times of unregulated transformer power supplies, traditional miniature circuit breakers (MCB) have established themselves as the main protection modules. However, when primarily switched-mode power supplies were introduced in the 1990s, they quickly replaced transformer power supplies in industrial applications.

The new technology enabled more efficient and compact power supplies that better met the increased demands of the industry. The era of transformers was thus over, but the MCBs remained and continued to be used in conjunction with switched-mode power supplies, even on the DC side. However, there are now much better and, above all, more reliable protection mechanisms, such as electronic circuit breakers.

MCB vs. eFuse

The biggest challenge is that miniature circuit breakers were originally designed for the AC-side of the application and require multiple times the nominal current for a few milliseconds to trip. Many switched-mode power supplies cannot provide this, as they shut down on the DC side during a high current pulse to protect themselves and the connected loads.

The alternative to the classic miniature circuit breaker (MCB) is an electronic circuit breaker (ECB) with integrated eFuses. These modules, such as our PISA models, are optimised for the distribution and protection of DC loads and do not require peak current for reliable and quick tripping. The reaction time, even with slight overload, is within 1 ms.

In this article, we explain some differences between MCBs and ECBs in detail, which can help you choose the right solution.

“Choosing the right MCB requires a precise understanding of the application and careful system planning. With an ECB, this effort can be significantly reduced.”

Abdul ÜcüncüApplication Engineer | Author of this blog article

Approval: MCB on the DC side only with IEC 60947-2

Most circuit breakers were developed for the protection of AC circuits. The idea that the same technology can also protect DC circuits is a misconception.

The main reason is that the arc burning and arc extinguishing properties of AC and DC systems are different. An AC circuit breaker may not reliably trip in a DC circuit. Therefore, if you want to use an MCB on the DC side in industrial low-voltage systems, it must comply with the IEC 60947-2 standard. This standard applies to MCBs whose main contacts are intended for connection to circuits with rated voltages in the low-voltage range of 1,000 VAC or 1,500 VDC.

Tripping characteristic: B, C or Z?

When selecting a circuit breaker, it is important to look at the tripping characteristic. There are different tripping characteristics suitable for various industrial applications. However, to reliably protect a DC circuit, it is advisable to use an MCB with the Z tripping characteristic.

Since circuit breakers with this tripping characteristic are more expensive, MCBs with the B or C tripping characteristic are mostly used in practice. As the graph shows, circuit breakers with a Z characteristic trip at 2 to 3 times the nominal current and are significantly faster than MCBs with a B characteristic, which trip at 3 to 5 times the nominal current, or even a C characteristic, which requires 5 to 10 times the current.

With an electronic circuit breaker, the selection of the tripping characteristic is much more flexible. As part of our PISA-M series, we offer an “adjustable” version where the tripping currents and characteristics can be flexibly adjusted. Thus, the tripping speed can be chosen between a fast (max. 2 ms) and a slow (max. 10 ms) characteristic.

The current values can be individually set for each of the 4 channels, as long as the total current does not exceed 20 A. With ECBs, users can respond much more flexibly to different loads or system expansions.

MCB: Tripping curves for B, C, Z and K characteristics

ECB: Tripping delay depending on current fast tripping characteristic.

Tripping curves for fast tripping characteristic

ECB: Tripping delay depending on current slow tripping characteristic.

Tripping curves for slow tripping characteristic

Tripping mechanism: Thermal and magnetic or electrical?

A circuit breaker has two types of tripping mechanisms integrated: thermal and magnetic tripping mechanisms.

The thermal fuse is responsible for tripping the circuit breaker in case of overload. Depending on the current level, tripping can take from a few seconds to 1-2 hours. The bimetal in the circuit breaker is responsible for the thermal tripping. When the current in the circuit breaker exceeds the nominal value, the bimetal heats up and deforms, triggering the shutdown mechanism. Since the current has the same thermal effect on both DC and AC sides, the thermal tripping works the same under defined environmental conditions for both DC and AC.

The magnetic fuse is responsible for the short-circuit tripping of the circuit breaker. It is supposed to trip within a few milliseconds in a specific tripping range (each tripping characteristic has its own range). The coil in the circuit breaker is responsible for this. When a very high current flows, a strong magnetic field is formed, which trips the switch.

Since the peak value of the alternating current determines the size of the magnetic field, a correction factor for the magnetic tripping must be taken into account when using a circuit breaker in DC circuits. This correction factor is √2 or 1.41. The immediate tripping ranges for circuit breakers with different tripping characteristics are described below.

An electronic circuit breaker, on the other hand, enables simpler and more precise tripping of the channels. The ECB continuously measures the current, and the integrated eFuse reliably and quickly trips at the defined current value. This process works independently of external influences, such as ambient temperature, which is a significant advantage over MCBs. An ECB directly contributes to higher system availability.

The tripping current of MCBs is always specified as AC in the datasheet and must be multiplied by 1.41 to convert to DC values; this graphic shows the AC current and the corrected DC current.

MCB: AC specification converted into DC values.

Temperature dependence and “Rated Diversity Factor”

As explained with the thermal fuse, the bimetal responsible for tripping is temperature-dependent. This means: the higher the ambient temperature, the more the bimetal heats up and trips earlier. High ambient temperature leads to the maximum nominal current flowing through the circuit breaker needing to be reduced to prevent unwanted tripping. Conversely, at low temperatures, a higher current must flow to sufficiently heat the bimetal to trip the circuit breaker.

The installation situation in the control cabinet can also affect the thermal fuse. When multiple circuit breakers are operated side by side without spacing, thermal interaction occurs between them. The circuit breakers heat each other, which means the maximum nominal current of the circuit breakers must be reduced again. How much the current needs to be reduced due to increased temperature of the MCB in such cases is specified by the manufacturer and referred to as the Rated Diversity Factor (RDF).

Electronic circuit breakers, on the other hand, are temperature-independent. The operating temperature of the PISA-M is between -25 °C and +70 °C at full output power, i.e., without derating. A Rated Diversity Factor is not necessary.

The modules can also be installed in the control cabinet without minimum spacing to other PISA-M units. Only a minimum distance of 15 mm to heat sources, such as the power supply, must be maintained.

Choosing the right power supply unit

Just as important as selecting the right circuit breaker is the decision for the appropriate power supply unit. This aspect is often overlooked.

Practice shows that the short-circuit current of a 10 A power supply for a total load of 7 A may not be sufficient to trip the MCB and isolate the faulty load. Because with a load of 7 A, a 10 A MCB is usually used. This means that if an MCB with the B characteristic is used, the 10 A power supply would need to provide between 30 A and 50 A as short-circuit current to trip the MCB. Most 10 A power supplies cannot provide this much current, as they shut down for self-protection beforehand. As a result, all loads connected to the power supply are no longer supplied, even if they do not have a fault.

To avoid this problem, a power supply with a fuse-breaking feature can be used, which provides 5-6 times the nominal current for a few milliseconds. Alternatively, the power supply must be oversized. This means using a higher power class. Both solutions have their disadvantages: users may pay for functions they do not need, and a larger power supply requires more space in the system. Even with a perfectly matched power supply to the MCBs, it may happen that the short-circuit current is not sufficient to trip the circuit breaker – for example, if the total resistance of the short-circuit path is too high.

If you want to combine a power supply with an electronic circuit breaker, only the available maximum output current of the power supply is relevant for the decision. For an ECB of the PISA-M type, we recommend a power supply with at least 90 W output power. The selection is thus much more flexible.

The 480 W DIN rail power supply CP20.248 features easy fuse breaking with 3 times the nominal current for 12 ms.

PULS DIN rail power supply: 24 V, 20 A CP20.248

Summary:

Choosing the right circuit breaker requires a precise understanding of the application and careful system planning. All this takes time, engineering resources, and ultimately money.

With every small change in the application, it must be determined again whether the circuit breakers still provide sufficient protection for the existing loads. With an electronic circuit breaker, this effort can be significantly reduced. In addition to wiring, only the configuration of the output currents needs to be done.

Our PISA modules with integrated eFuses protect loads by reliably tripping affected channels, regardless of the load, temperature, power supply, or total resistance of the short-circuit path.

UPS systems ensure greater reliability in critical infrastructures

Power Supply

Application

Critical Infrastructures

Dc-Ups

In this blog article, you will learn why UPS systems are indispensable for ensuring a reliable and stable power supply in critical infrastructures, which components are needed for this, and which standards they must meet.

In the past 100 years, electricity has always flowed in one direction – from the producer to the consumer. However, new technologies, innovative ways of energy procurement and generation, as well as comprehensive digitalisation, are fundamentally changing the market. The successful integration of innovative components is crucial to actively shaping climate change and ensuring sustainable success.

The infrastructures for electricity, gas, water, and heat extend over vast supply areas and decentralised stations. Their smooth operation is of fundamental importance. Disruptions must be detected and resolved immediately, as they can have significant impacts on all areas of life within a short period. For this reason, these critical areas have been grouped under the term Critical Infrastructures (KRITIS).

KRITIS includes facilities and organisations whose failure or impairment can lead to significant supply shortages or disruptions to public safety. These infrastructures are essential for the functioning of our society and include sectors such as energy, information technology, telecommunications, transport, health, and water.

Ronald Block
Regional Sales & Industry Development Manager at PULS

“At PULS, we believe in adding value to our customers’ business. The greatest value for modern electrical grids is stability, and our power supply solutions ensure a high degree of reliability and trust.”

Ronald BlockRegional Sales & Industry Development Manager | Author of this blog article–LinkedIn

Requirements for power supply systems in critical infrastructures

In this blog article, we examine the requirements for power supplies and DC UPS systems in critical infrastructures, as well as the relevant standards that play a role in this context.

Uninterruptible power supply (UPS) is indispensable in critical infrastructures. Energy supply companies use DC UPS systems in combination with remote control technology to protect the control systems of their power plants and to ensure the integration of renewable energies through transfer stations and distribution networks such as local secondary substations. The focus is on monitoring and controlling spatially remote objects.

Specific requirements for power supplies and UPS systems in critical infrastructures concern reliability, robustness, and security:

Avoidance of downtime:
UPS systems ensure an uninterrupted power supply during power outages and enable an orderly shutdown of systems during prolonged outages.
Protection against voltage fluctuations:
UPS systems protect sensitive equipment from voltage fluctuations and power surges that could cause damage or data loss. This is essential for IT infrastructure and communication systems.
Increase in operational safety:
By providing a stable power supply, UPS systems contribute to overall operational safety and minimize the risk of operational interruptions.
Compliance with legal requirements:
Many critical infrastructures are legally required to take measures to ensure a continuous power supply. UPS systems help meet these requirements and ensure compliance with relevant standards and regulations.

Relevant standards and guidelines for critical infrastructures

The power supply in critical infrastructures is of paramount importance for the safety and well-being of society. By adhering to relevant standards and guidelines, operators can ensure that their systems function reliably and safely. Here are some of the most important ones:

§14a EnWG: Regulates the grid-oriented control of controllable consumption devices and controllable grid connections.
VDE-AR-N-4105: Technical minimum requirements for the connection and parallel operation of generation plants in the low-voltage network, a national standard for the grid connection of generation plants in low voltage.
VDE-AR-N-4110: Forms the technical basis for the connection and operation of customer systems to the medium-voltage network.
BSI-Kritisverordnung: This regulation defines which facilities are considered critical infrastructures and what security requirements they must meet.

Traditional gridFlexible grid

Network operators are obligated to ensure a stable and reliable power supply. The grid must adapt to the increasingly flexible energy flow. Uneven consumption situations and generation, higher loads, and the feed-in of decentralised electricity cause voltage fluctuations.

Peak loads with unknown simultaneity factors pose a significant challenge. The following elements have the greatest impact:

PV systems
Heat pumps
Battery storage
E-mobility

These requirements from different perspectives, as well as the climate goals of the German federal government, lead to a massive expansion of the energy infrastructure. Experts expect that the energy supply infrastructure will need to be doubled to meet the climate goals.

The constantly growing share of renewable energies also contributes significantly to the strong growth in this sector. Current studies, such as the study by the Hans Böckler Foundation, predict a doubling of the investment volume in the coming years.

In demanding environmental conditions, the right hardware is crucial

The development of UPS systems for critical infrastructures is driven by technological innovations and the integration of new technologies. These trends help improve the reliability, efficiency, and safety of power supply in critical areas.

A significant trend is the introduction of modular UPS systems. These offer flexible and scalable solutions as they consist of several independent modules that can be added or removed as needed. This facilitates adaptation to growing demands and increases redundancy.

Additionally, UPS systems are increasingly being integrated into smart grids. This integration enables better monitoring and control of the power supply, which increases efficiency and reliability. Smart grids can also better incorporate renewable energy sources and improve grid stability.

Another important aspect is the retrofitting of existing infrastructure in local substations with so-called retrofit solutions. These solutions measure the outputs and provide data for extended network planning to take appropriate measures in case of failure. The installation situation of the devices is often challenging, as the standardized form factor of a load switch strip is frequently used as a housing specification.

Finally, there is a growing trend towards the development of environmentally friendly UPS technologies. This includes the use of renewable energies, the reduction of the carbon footprint, and the improvement of energy efficiency.

Retrofit UPS system solution for digitisation of local substations.

High ambient temperatures are the biggest “challenge”

As PULS Group, we support our customers in finding optimal power supply solutions for the aforementioned requirements. We place great emphasis on well-managed project planning and the easy integrability of our systems. The following properties are particularly important to our customers: lifetime, size, and temperature range.

Local substation in the electrical grid.

Power supply solutions for substations in local distribution networks.

There are special requirements, especially regarding operating temperatures and the associated lifetime. The reason for this is the harsh environmental conditions often found in non-air-conditioned outdoor areas.

We consider a “robust” environment with partial direct sunlight in a local substation and use the annual temperature profile of Tönisvorst (a city in North Rhine-Westphalia) from the year 2022. Here, the highest ever recorded outdoor temperature in Germany of 41.2 °C was registered. Such a high outdoor temperature means that temperatures of over 75 °C can occur in active local substations in Germany.

This maximum requirement forms the basis for the offset applied to the temperature profile to simulate the maximum load on the installed components. This means that a permanent load of over 70 °C is not assumed, but rather a temporary peak temperature on several days per year.

This detailed simulation is very useful, as the trend towards warmer years and higher peak values due to climate change is demonstrably present.

Software simulation helps in choosing the right components

To optimally specify our solutions for high temperatures, we conducted a detailed lifetime simulation at the component level using software. Based on the results and the requirement that the devices must achieve stable buffering of full performance for more than 10 years, we selected the components and designed the corresponding circuitry.

To ensure reliable operation, it is crucial that the devices do not shut down even at temperatures above 70 °C. In the event of a necessary safety shutdown, they must also restart independently.

Heat has a negative impact on the lifetime and reliability of DC-UPS and power supplies

The minimum lifetime of DC-UPS and DIN rail power supplies is determined by the lifetime of electrolytic capacitors, which are the most critical element in the devices. Even a temperature increase of +10 °C in the power supply halves the lifetime of the capacitors.

To achieve the longest possible lifetime of DIN rail power supplies and DC-UPS, it is therefore important that the devices are protected from overheating. The cooling concept chosen during the development of the power supply plays a crucial role.

Ideally, the devices are designed to generate as little heat as possible from the outset. This is achieved through high efficiency and correspondingly low power losses. Since losses cannot be completely avoided, it is essential to efficiently dissipate the resulting heated air from the device.

Efficient cooling concept for long-lasting power supplies: The “Cool Design” by PULS

To ensure a long lifetime for power supplies, it is essential to minimise heat generation within the devices. With the “Cool Design” concept, PULS defines the interaction of three key factors that lead to low heat generation: firstly, consistently high efficiency; secondly, optimised dissipation of heat to the device’s surroundings; and thirdly, the thoughtful arrangement of temperature-sensitive components within the device.

In terms of DC-UPS systems, PULS has so far pursued the approach of realising the power supply and the DC-UPS module with separate devices, rather than integrating both functions into one housing. This separates the power supply, as the primary heat source, from the sensitive electrolytic capacitors in the UPS module.

However, PULS’s latest subsidiary Adelsystem – a PULS company has been successfully offering an all-in-one solution for several years, combining a power supply and a DC-UPS in one device. The Italian developers have chosen a smart device concept for this approach, which we will discuss in a separate blog article.

3 principles of “Cool Design” by PULS

DC-UPS – with battery or capacitor storage?

Currently, PULS offers two options for an uninterruptible power supply to the load in an emergency: both double-layer capacitors and lead-acid batteries can serve as energy storage in DC-UPS systems for industrial applications.

Double-layer capacitors, also known under trade names such as Ultracaps, Supercaps, or Greencaps, have been available on the market for over 25 years and have developed into reliable and proven components. These initially quite expensive components are suitable as energy storage for DC-UPS systems and can be used in applications such as storing braking energy or providing short peak currents.

Which energy storage solution is suitable for which application cannot be answered in general. Each application is individual and therefore requires a specific analysis to ensure the best possible uninterruptible power supply.

The following questions can help find the ideal backup solution for your system:

What output voltage is required?
How much current must be available as a reserve?
How much backup time is required?
Are there loads in this application that do not need backup, and if so, how many?

Based on this information, recommendations can be made for the required output power of the power supply, the backup method, and any additional devices that may be needed. Of course, proven standard combinations that are often used by our customers and are typical for the industry also result from the corresponding requirements of the standard.

Buffering times of DC back-up solutions.

Summary:

Reliable power supply in critical infrastructures is of paramount importance for the safety and well-being of society. By adhering to relevant standards and guidelines, operators can ensure that their systems function safely. The use of modern technologies also allows for the benefits of renewable energies to be harnessed while addressing the associated challenges.

UPS systems are indispensable for ensuring a reliable and stable power supply in critical infrastructures. They protect against outages, voltage fluctuations, and data loss, thereby contributing to the safety and efficiency of operational processes. Implementing UPS systems in critical infrastructures is complex and requires careful planning and good consultation with the manufacturer. Despite these challenges, UPS systems are essential to guarantee the reliability and safety of power supply in critical areas.

Determining which UPS system is suitable for which application cannot be answered in general terms. Each application is unique and therefore requires a specific analysis. However, industry-specific application fields also define proven device combinations. Feel free to contact us, and we will find the right solution for your application.

We see a global shift towards a data-driven economy developing at unprecedented speed which heavily affects the future role of data in the manufacturing industry. Therefore smart manufacturing is becoming increasingly important, data-driven insights are crucial for optimising system performance and ensuring operational efficiency. The power supply is placed at a central nodal point in every system and records a significant amount of real-time information that is of particular interest to the operating company as well as the system manufacturer.

A growing line-up of PULS power supplies give you access to this information via IO-Link or EtherCAT. In this blog article you will learn how you can profit from those solutions now and in the future.

What is the condition of the power supply? Do you still have enough power left to supply further modules inside the cabinet? What is the quality of the mains voltage like? And how does the temperature develop inside and outside of the power supply?

Many PULS power supplies are able to answer these questions with real application data. This information can help to tackle the big questions within the application: Is your system running at its optimum and as expected? If not, which adjustments need to be made?

Knowing the answers can help increase system availability and reduce maintenance and operating costs. And last but not least, reliable data is the key to success in smart manufacturing. This means the power supply has the potential – in parallel with its function as a converter – to also act as a sensor and therefore makes a significant contribution to your approaches for predictive maintenance and automation of industrial processes, which leads to a higher output, better performance and lower costs.

Power supplies with a communication interface strengthen availability of the overall system

Power supplies perform a rather more passive role in terms of communication output. Following installation, they need to work reliably in the background and remain as maintenance-free as possible – ideally for many years.

So the question which communication protocols a power supply manufacturer like PULS should support in the long-term is essential and must be well considered. Based on many meetings with various customers and market analysis we decided to go for IO-Link and EtherCAT. The reasons for this decision are explained in this article.

Therefore we are extending our portfolio with IO-Link and EtherCAT versions of our most popular products.

CP20.248-IOL with IO-Link interface and display

For example the reliable and efficient 1-phase 480 W DIN rail power supply CP20 is available as an EtherCAT (CP20.241-ETC, CP20.481-ETC), IO-Link (CP20.242-IOL) version as well as a hybrid version with IO-Link and an integrated power supply condition display (CP20.248-IOL). For the higher power demand, the well-established 3-phase 960 W DIN rail power supply QT40 comes with IO-Link. These devices are ready for a simple integration into existing communication networks. Our robust IP54, IP65 and IP67 Field Power Supplies (FIEPOS) for decentralised applications feature IO-Link as well and another variant supporting EtherCAT is under development.

With all these new tools at hand customers profit from a future-proof solution that alongside a highly efficient and reliable energy supply embedded in a compact housing, also provides completely new insights into the performance requirements and physical processes of their systems or machines. This valuable information can be used to to better understand what is really going on in the application to optimise the availability and capacity utilisation of the system. In addition, the data helps to reduce energy costs, permits needs-oriented, preventative maintenance and provides valuable information for sustainability reports.

Remote diagnostics and automated parameterisation

The connection via IO-Link or EtherCAT also facilitates remote diagnostics and parameterisation via the user software being applied in the automation system. The system engineer can set the output voltage via the configuration software and the devices can be switched on and off remotely assuming remote access is enabled in the user software.

The settings made by the user, as well as critical process values, are saved on the automation system with full resistance to voltage failures and simultaneously on the built-in non-volatile memory in the power supply. If a device exchange becomes necessary, rapid, automated parameterisation of the new device is carried out during ongoing operation – in accordance with the parameters stored on the automation system. Downtime due to maintenance work is therefore avoided in the long term.

The data sent by the power supply also provide information on the cause of the fault and simplify problem-solving. This data is categorised in cyclical data, acyclical data and events.

The output current is included in the process data, for example, and is communicated to the master in a cyclical data telegram. The acyclical signals include device information such as input and output parameters that can be queried at all times.

Special events are also reported by the power supply. These events could be warnings or error messages, such as too low or too high input voltages, an overload or too high temperatures. If an abnormal condition arises, the power supply sends a message to the IO-Link or EtherCAT master and displays to the user the need for action, even before a failure actually occurs. Maintenance is therefore preventative and needs-oriented. This means that rigid cycles of regular servicing work are no longer required. In turn, this saves costs on new purchases and maintenance.

Additionally, events or warnings can trigger application reactions. In the simplest case, this can establish a safe state of the system. Furthermore, it is even possible to completely avoid system downtime based on the communicated events and therefore prevent insufficient product quality.

Now let’s dive deeper into the advantages of IO-Link and EtherCAT.

Advantages of the IO-Link communication protocol

IO-Link is based on serial, bidirectional point-to-point communication. The system is very robust overall and also has a high level of security – two factors that PULS pays particular attention to in the development of its industrial power supplies. The devices are often exposed to the harsh environments of the lower automation level and at the same time need to be protected against sabotage from outside. Data transmission via IO-Link is tried and tested for this usage.

The component costs for an IO-Link port in the power supply is relatively low in comparison to more complex communication protocols. Due to the low number of additional components, the MTBF value (Mean Time Between Failures) is almost as high as for the products without IO-Link. E.g. the MTBF for the QT40.241 (without IO-Link) is 375,000 h and for the QT40.241-IOL (with IO-Link) 350,000 h. This means that there are no compromises in terms of the reliability of the devices.

The same also applies to the long lifetime of 62,000 hours – at 3AC 480V, continuous full load and +40°C ambient temperature. This makes the IO-Link-compatible power supplies particularly well suited to failure-critical applications, such as in the automotive industry, factory automation and process industries.

In addition, IO-Link has been designed from the ground up as a user-friendly plug and play solution. Installation and operation are simple and can be realised cost-effectively. Standard shielded IO cables are all that are required for the cabling. Integration capability in all standard field bus and automation systems is ensured, offering flexible usage options.

Additional advantages of the EtherCAT communication protocol

The integration of the available PULS power supplies with EtherCAT interface into existing EtherCAT networks is very easy and works without additional gateways, which is a big plus for users who already rely on this field bus solution.

The biggest benefit of EtherCAT is its real-time capabilities, high-speed data transmission and easy integration, which outperforms any other industrial communication. This allows the power supply data to be used within real-time control loops. Based on the data, drives and other high-energy users can be optimally controlled to maintain overall dynamic power needs at their optimum level.

The data enables improved system efficiency as power supplies can be used at the optimal operating point. This leads to increased system throughput, improved product quality, and reduced waste, ultimately benefiting end-users by delivering better results due to the consistent performance and minimal disruptions.

Power supplies with EtherCAT interface are ideal for maintenance, logging and remote control in large-scale systems.

DIN rail power supply with EtherCAT interface

Have you ever heard of ADELBus?

The newest member of the PULS Group, Adelsystem – a PULS company, has developed its own communication network for its DC-UPS solutions, called ADELBus. This network allows the connection of all components in a system using a single communication protocol based on MODbus-RTU or CANbus technology, depending on the application field.

ADELBus enables the remote monitoring and control of all system parameters. It is designed to be simple yet powerful, providing robust and versatile communication capabilities for various industrial applications.

Learn more

AI decisions in the factory based on digital load profiles

The data recorded by power supplies with IO-Link or EtherCAT forms the basis for the technical innovations of the coming years. Above all, PULS is thinking here of the importance of machine learning in combination with the ongoing progress in terms of artificial intelligence (AI). The power supply is already supplying precise measurements of the output current, in other words, the load current. On the basis of these very carefully measured values, it is possible to detect and describe digital load profiles.

Based on information on the output current, for example, it is possible to determine whether or not a load changes across an extended period. This change can be an indication of signs of wear in the machine or plant. As an example, in the case of knocked out profiles, a sinus curve would be detectable in the load profile. As part of computer-aided data analysis based on artificial neural networks, this anomaly would be detected and reported.

Data is also provided by many other system components in parallel. Certain patterns can be recognised in these data sets and linked to operating states. The next step would then be a similarly automated decision-making process on the subsequent procedure using AI. This approach means that the power supply and other components as data sources open up entirely new options in the use of AI in the factory environment.

The use of current as a standardised data source in the production process plays an important role here. As a physical value, current supplies precise, interpretable and reliable data. This means that common big data problems in established company structures, such as incompatibility and inconsistency of data, or difficulties in networking and scaling, can be avoided.

Simplified artificial intelligence (AI) process for power supply data in industrial applications.

Summary: Let power supply data work for you

In conclusion, leveraging your power supply unit as a data source offers significant advantages for both operating companies and system manufacturers. By integrating PULS power supplies with IO-Link or EtherCAT, you gain access to valuable real-time information such as output current, voltage levels, temperature development, and load on the power supply. This data enhances system availability and reduces maintenance costs while supporting predictive maintenance and automation of industrial processes.

With the addition of communication interfaces, power supplies play a more active role in system diagnostics and parameterisation. The integration of IO-Link and EtherCAT into PULS power supplies ensures compatibility with existing networks and provides robust, real-time data transmission. This enables remote diagnostics, automated parameterisation, and efficient maintenance, ultimately leading to improved system efficiency, reduced energy costs, and enhanced overall performance.

Moreover, these systems are ready for an AI-shaped future. The data recorded by power supplies with IO-Link or EtherCAT forms the basis for technical innovations, including machine learning and artificial intelligence applications. This opens up new possibilities for optimising system performance and predictive maintenance.

Explore the benefits of these advanced power supply solutions and discover how they contribute to the success of your smart manufacturing initiatives.