Fundamentals of Safety Protection Technology Where there are machines, there is danger; where there is danger, there is a need to protect people. This is not only a legal requirement but also a responsibility and obligation of enterprises. After nearly 120 years of development, factory and machine safety protection technology has evolved into numerous international and national standards, resulting in a wide variety of safety protection products that conform to and meet these standards. Representative standards include the EU EN series standards, the US ANSI standards, and IEC international standards. For machines alone, these standards stipulate that a moving machine poses a greater threat to people than a stationary one. Therefore, most machine safety protection technologies aim to stop machines as quickly as possible when necessary, reducing danger and minimizing property damage and human injury. Common safety protection products include a wide variety of switches such as safety switches, safety door (lock) switches, safety hinge switches, safety magnetic switches, safety edge/carpets, safety pull cords, and safety foot switches, as well as complex electronic products such as safety relays, safety PLCs, AS-I safety bus systems and their components. Safety Mat Protection System Among various switch protection elements, safety mats, as a special type of protective switch, are characterized by their wide protection range, low price, long lifespan, safety and reliability, flexible and convenient installation, and ability to keep on-site passages clear and facilitate material transportation, thus gaining widespread application. Currently, safety mats are widely used around robot units (Figure 1), laser welding and cutting equipment, packaging machines, woodworking machinery, stacking and packaging machines, raw material processing, metal pipe bending equipment, and stamping equipment (Figure 2), among other places. The SMS3 series safety mats, as safety protection switch elements, must be used in conjunction with safety relays and laid on the ground around hazardous machinery and equipment to warn of dangerous areas and protect people and machines. Their working principle is as follows: when a person steps on the mat, the mat senses a pressure change and outputs a switch signal. This signal is detected by the safety relay, amplified, and then output as a switch signal, directly cutting off the power supply to the machine, thus protecting people and machines. Due to the special function of safety mats, safety must be ensured throughout the entire control process; therefore, continuous detection by the safety relay is required to ensure the safety of personnel entering hazardous areas. Safety mats are sensitive pressure switch elements, manufactured in accordance with European standard EN1760-1. When used with safety relays in the AZR series, they significantly improve reliability and safety levels, meeting the safety level 3 requirements of EN954-1. The SMS3 safety mat (Figure 3) is a press-activated contact switch. While its working principle is simple, its manufacturing process and structure are relatively complex. It is molded in one piece using hot-melt plastic, thus requiring no maintenance. It is waterproof, oil-proof, and resistant to mineral and plant acids, petrochemicals, and organic solvents, achieving an IP67 protection rating. A specially designed anti-slip surface prevents operators from slipping. The two layers of elastic steel plates can withstand a pressure of 2000 N/cm², while the operating force is very small, only 6 N/cm². With a thickness of only 12mm and specialized edge strips for fixing, it achieves 100% response area and prevents tripping. The 6m long sol-gel sheathed lead wire allows users to freely splice various shapes and required areas, up to a maximum of 20m². Its numerous advantages make it suitable for almost all working environments, even harsh conditions such as dampness, oil, and corrosive environments. A structural cross-section of the safety mat is shown in Figure 4. In the figure: 1—Anti-slip surface; 2—Upper electrode steel plate; 3—Edge; 4—Conductive strip; 5—Compressible elastic insulating strip; 6—Lower electrode steel plate; 7—Carpet bottom surface. Calculation of Safety Distances When using safety mats, it is necessary to consider: what area should be covered in a hazardous area requiring protection to achieve both safety and economy? Here, a commonly used standard—EN999—needs to be introduced. EN999 is a standard related to safety distances, mainly introducing methods for defining the location of safety protection devices in machine safety based on the speed of human limb movement. For safety mats, the potential threat to people entering the hazardous area due to the lag caused by the response speed of the mat and control system must be considered, especially in cases of rapid entry. In other words, when designing and calculating safety mats, it is necessary to determine not only the installation location of the mat but also the area it covers to ensure that the machine is in a safe state before a person steps onto the mat and reaches the hazardous machine. When using SMS3 series safety mats for area safety protection, the design and installation must be carried out in accordance with the requirements of safety standard EN999 to fundamentally prevent personnel from crossing the mat into the hazardous area or approaching the hazardous area by going around the mat. This standard provides formulas for calculating safe distances when using different safety protection switches. For safety mats, the simplified formula is: S = K(T1 + T2) + 1200 Where, S—minimum safe distance, i.e., the minimum distance from the hazardous point of the machine to a person stepping onto the mat. Unit: mm. K—empirical coefficient, usually derived from the movement speed of a person and their limbs, generally taken as 1600. Unit: mm/s. T1—total response time of the mat switch and safety relay system. Unit: s. T2—total response time of the machine system, unit: m. Safety mats are only truly effective when installed according to EN999 standards, ensuring safe distances are maintained from all possible entry points into the hazard area. The idea that any safety mat is sufficient regardless of size or the presence of safety relays is dangerous. SMS 3 series safety mats, being pressure-sensitive components, require careful handling during transport and installation. Handle them horizontally and avoid dropping them from heights or throwing them. Inspect and clean the floor before and after installation to ensure it is clean, flat, and smooth, free of hard protrusions or foreign objects. During use, prevent sharp or hard objects from landing on the mat and clean it regularly. These precautions will help ensure proper use and extend the lifespan of the safety mat. With proper design, installation, and use, a safe path is at your feet. With technological advancements and the increasing automation and complexity of machines, safety protection technologies will continuously develop and progress to meet these needs. Currently, photoelectric and resistive safety mats have been developed and designed, and it is certain that safety mats will see wider and wider application. Because pursuing safety is our eternal goal.