Connected and Highly Automated: Every Component Counts!
Our fully electrified and highly connected world would be unthinkable without the automation of industrial production processes. And even if plugs and sockets, switches and circuit protection devices do not receive the greatest attention, they are still of fundamental importance for the economically viable use of highly automated production processes.
It is worth taking a look back in history: the mechanization of manual work steps began as early as the first industrial revolution (end of the 18th century) – steam engines drove looms and other machines for the first time. Electrification followed with the second revolution in the 19th century: electric motors replaced steam engines, and electrical safety devices and relays made the first rudimentary control systems possible. The third industrial revolution, beginning in the 1960s, brought digital technology: programmable logic controllers (PLCs) and microprocessors enabled flexible, software-supported automation solutions. At the same time, standardized fieldbuses and input/output modules were developed.
Today – in the age of Industry 4.0 – machines, sensors and actuators are networked via Ethernet-based protocols (e.g. Profinet, EtherCAT). Data is analyzed in real time and stored in cloud or edge architectures to further increase efficiency and quality.
Reasons for Increasing Automation
The degree of automation in industry is growing, primarily because it significantly increases productivity: automation systems can run around the clock, work at a consistently high speed and eliminate human error. At the same time, automation ensures a noticeable increase in quality, as automatic control loops and sensors detect fluctuations in the production process and correct them immediately. From an economic point of view, automated processes reduce unit costs due to lower personnel costs and fewer rejects. Another important aspect is flexibility: modern programs and control systems can be quickly reconfigured for product changes without the need for mechanical conversions. Finally, automated systems also increase occupational safety by taking over hazardous or unhealthy activities and thus reducing the risk to personnel.
Pros and Cons
Automated systems offer very high availability and achieve cycle times that are unattainable for manual processes. They work precisely and reproducibly, which means that the quality of the end products remains consistently high and material losses are minimized. In addition, they create transparency along the entire process chain through data acquisition, which can be used for optimization and preventive maintenance. However, this is offset by high initial investments in technology, planning and engineering as well as the complexity that requires specialized personnel for commissioning and maintenance. In addition, there is a certain dependency on global supply chains: bottlenecks in components or control systems can bring production to a halt. Last but not least, there are additional requirements for IT security and data protection, as many systems are now networked and therefore potentially vulnerable.
Automation Components Buttons and Control Elements
Pushbuttons and switches are the primary interfaces between man and machine: for example, they enable Optical switches use infrared or light barrier technology to detect the operating hand. They are mainly used where any contact is to be avoided or in clean rooms in the pharmaceutical and semiconductor industries. The sensitivity can be very high, but optical scanners are susceptible to soiling and require regular cleaning and calibration.
Finally, inductive and magnetic systems to be started and stopped, parameters to be set or an “emergency stop” to be triggered in an incident. A basic distinction is made between mechanical pushbuttons, capacitive (non-contact) and optical variants, as well as special forms such as magnetic or inductive switches.
Mechanical pushbuttons are based on real contacts that are closed or opened when pressed. They are characterized by a clearly perceptible switching characteristic and a very long service life (up to 10 million or more switching cycles). Thanks to robust materials (metal cover, reinforced plastic friction elements), they achieve protection ratings of up to IP65 or IP67 and are insensitive to temperature fluctuations.
Piezoelectric switches are based on the piezoelectric effect, in which very specific materials generate electrical voltage when subjected to mechanical pressure. Pressing the button generates a voltage that is used to trigger the switching process. This technology is extremely robust as it contains no moving parts and is therefore suitable for applications that require high reliability and durability. Piezoelectric switches are resistant to mechanical stress and and can be made waterproof.
Capacitive switches react to the change in the electrical field when an operating finger comes close to them. They enable non-contact operation – ideal in hygienic environments or environments susceptible to unwanted contamination (e.g. food technology, paint booths). The sensitivity can be finely adjusted and they offer a practically unlimited service life as there are no mechanical wear parts. However, they often require good earthing and shielding to avoid false triggering.
switches register metal objects or magnetic signals and are usually used in robust machine environments for position or end position monitoring. They are extremely resistant to dirt and moisture and have a long service life. Modern operating elements often have integrated LEDs for status displays, can be combined with various actuator types (NPN/PNP, NAMUR) and are certified in accordance with standards such as IEC 60947-5-1 and EN 60204-1.
Resistive touchscreens are based on pressure sensitivity and can also be operated with gloves. They are cost- effective and insensitive to soiling. Capacitive touchscreens, on the other hand, offer high-precision control and support multi-touch functions, but are more sensitive to moisture and chemical “influences”. The service life of resistive touchscreens is between 5 and 10 years, while capacitive variants can last between 7 and 8.5 years.
Input and Sensor Systems
Sensory input systems range from simple mechanical proximity switches and inductive and capacitive proximity sensors to complex vision systems and RFID readers. They detect physical variables such as position, speed or material properties and supply digital or analog signals to the control system. To ensure maximum reliability, these sensors are usually housed in stainless steel or PBT housings, meet protection classes from IP67 to IP69K and are EMC-tested in accordance with IEC 61000.
Connectors
In addition to the plug connections for the power supply in accordance to IEC 60320, standardized plug connectors (M8, M12, Industrial Ethernet RJ45) are used in field cabling, which guarantee quick assembly, clear polarity definition and high contact pull-in forces. They typically have to function fault-free over 1000 mating cycles, withstand vibrations and shock loads (approval in accordance with DIN EN 60068-2) and are EMC- optimized thanks to shielding concepts..
IP Protection
When using pushbuttons, switches and other operating elements as well as plug-in devices and connectors in industrial environments, protection against the ingress of foreign particles and water is essential. The IEC 60529 standard defines the IP protection system (“Ingress Protection”), consisting of two digits. See the table below: The precise selection of IP protection classes ensures that your operating elements and connectors work reliably in their intended environment over the long term – without the ingress of dust, splash water or chemicals.
Device Protection
Overcurrent protection is provided locally with appropriate fuses (operating class gG for general protection, aM for motor protection) or miniature plug-in fuses in small machine distribution boards. Important characteristic values are the rated current spectrum, the breaking capacity (e.g. 150 A at 500 VDC) and the characteristics. Low-voltage high- capacity fuses (NH) are used in main distribution boards.
Circuit Breaker
Circuit breakers integrate overcurrent and short-circuit protection (miniature circuit breakers) and, depending on the type, residual current protection (RCCB/FI). For operation with frequency-controlled drives, B or A-type RCCBs are used so that high HF components in the residual current are not interpreted as faults. Selectivity in the system design and fast switch-off times (≤ 0.1 s) minimize failure areas and increase personal protection at the same time.
Reliability and Longevity
Reliability in industrial automation is based on redundant safety circuits, continuous monitoring and predictive maintenance strategies that detect failure probabilities at an early stage. Components with a service life of ten million or more switching cycles – such as pushbuttons and plug connections – reduce maintenance costs and lower the total cost of ownership. EMC compliance is essential in harsh environments: shielded cables, correct earthing concepts and interference suppression filters in frequency inverters protect control cables and sensors from interference pulses. This ensures signal integrity and minimizes the risk of failure.
Safety Standards
In addition to the general machine safety standards, there are a large number of industry-specific specifications for automation solutions that take into account particular hazards and company-specific processes. The most important regulations for industries with special requirements, such as the chemical and automotive industries, are listed below:
Chemical Industry
1. ATEX Directives (Europe)
ATEX 95 / 2014/34/EU (Equipment and Protective Systems for use in Explosive Atmospheres): It specifies which devices and protective systems are permitted in potentially explosive atmospheres.
ATEX 137 / 1999/92/EC (Safety and Health of Workers potentially at risk from Explosive Atmospheres): This directive defines the employer's obligations to protect employees.
2. IECEx System
International counterpart to ATEX: Certification of components and systems in accordance with IEC 60079 standards.
Automotive Industry
1. ISO 26262 – Functional safety of road vehicles. Applies the safety lifecycle approach of IEC 61508 to vehicle development. Defines Automotive Safety Integrity Levels (ASIL A to D).
2. ISO 21448 – SOTIF (Safety of the Intended Functionality). Supplementary to ISO 26262: Addresses hazards that are not caused by malfunctions but by
inadequate specifications or external circumstances.
3. IATF 16949 (Quality Management) While this is primarily a QM standard, it also requires documented risk analyses and measures with regard to the safety and reliability of production technology.
Interaction with General Standards
In both industries, the industry-specific regulations are always applied in addition to the general standards relating to machine safety in accordance with ISO 12100, IEC 62061 and ISO 13849 as well
as IEC 60204-1. Industry specifications add additional requirements that must be fully taken into account in the safety engineering process.
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