Before equipment operation, switches and sensors can be used to check whether components, doors, and safety devices are properly locked. These locks are crucial for ensuring production accuracy and the smooth and safe operation of equipment. However, all wired devices—whether limit switches or proximity sensors—are not only limited in their application area but are also prone to wear and tear, requiring continuous maintenance.
Currently, proximity sensors are widely used in factory workshops, simply because they are cheaper than traditional electromechanical switches. However, many manufacturers have found that proximity sensors require reactive maintenance from time to time, causing production interruptions.
In multi-axis machining (such as engine casting), the fixture continuously rotates the workpiece to ensure proper positioning. This causes the proximity sensor's wires to move and bear stress, leading to gradual wear and eventual breakage. Once a cable breaks, the equipment and workers are idle due to cable replacement (which typically takes 15 to 20 minutes). If the cable is replaced every three months (as some manufacturers do), the cumulative productivity loss becomes substantial. Preventative maintenance, by anticipating when maintenance will be needed, can avoid downtime caused by repairs.
Similarly, metal shavings brought down from the processing area by the coolant continuously come into contact with the wires, constantly wearing down the cable sheath and potentially causing short circuits or continuity problems. In such cases, the cable must be replaced, resulting in lost productivity.
Another major challenge manufacturers face with sensors and devices is the number of connection points. Each connection point is a potential source of failure. Eliminating these connection points can reduce the frequency and duration of production disruptions.
Wireless limit switches easily solve all the above problems. Extensive use in factory workshops has proven that wireless technology (especially 802.15.4.2.4GHz) is a reliable solution. Integrating wireless technology into the switch offers the following advantages: the switch itself does not consume power, only performs control functions—this can extend battery life to two years or more under normal operating conditions. Built-in diagnostics in the RF (radio frequency) circuitry provide low battery indication, allowing malfunctioning batteries to be replaced before work processes are forced to stop. This is crucial because both the sensors and RF circuitry consume significant amounts of power and require regular battery replacements.
Wireless switches can be easily added to applications using standard wired switches or proximity sensors. Of course, regardless of the wireless device used, an RF (radio frequency) signal needs to be transmitted and converted to a standard input signal (PNP, NPN, or relay) usable by the control system. This is achieved through a wireless receiver installed in the device's control panel. The receiver's output connects directly to the controller input card in a traditional wired manner. The controller cannot distinguish between standard inputs from wireless and wired devices. The only difference is the addition of additional diagnostic inputs for monitoring battery life and signal strength.
Wireless technology has revolutionized factory automation by reducing switch installation costs and providing greater application flexibility. Eliminating the need for cables allows manufacturers to significantly reduce maintenance costs, avoid downtime caused by connector and cable integrity issues, and dramatically increase productivity. With the continuous release of new solutions and the wider application of wireless technology, using wireless devices to solve application problems will undoubtedly lead a new trend in factory automation technology.
