Force Guided Relays
Force guided relays are electromechanical switching devices that are designed to implement safety functions and reduce risk. When an error occurs, or a detection zone is violated, the safety relay will initiate a safe and reliable response. A traditional relay uses an electromagnet with an electrical coil wrapped around a core of ferromagnetic material. Safety relays are similarly constructed. However, they also use force guided contacts and electronic components with fault-proof semiconductor outputs. They must be designed in such a way that neither an internal equipment fault nor an external fault caused by the actuator or sensor will compromise safety.
Traditional relays use the mechanical movement of metal contacts to switch a load on or off. The metal contacts have the potential to weld shut after repeated operation cycles, causing the machine to continue running even after an operator activates an emergency stop process. For this reason, safety relays are required for hazardous machinery.
Force guided relays are electromechanical switching devices that are designed in such a way that it is not possible for all contacts to be closed at the same time. If a normally open contact fails when trying to open, the associated normally closed contact cannot close when the power supply is switched off. Force guided relays are used in safety circuits in combination with emergency stop switches, interlock switches, and light curtains to control outputs. They can also be used to expand outputs for safety controllers and safety relay modules.
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FAQs
What is the entire service life of a force guided relay?
The service life of a force guided relay can vary depending on several factors, including the specific model and brand, the operating conditions, and the application in which it is used. Force guided relays are designed to provide reliable performance and long service life, typically lasting for many years in typical operating conditions.
What safety control applications are force guided relays used?
Force guided relays are commonly used in safety control applications where reliable switching and monitoring of safety circuits are essential. These include: emergency stop systems, safety interlock systems, light curtains and safety sensors, safety monitoring systems and safety relays for machine guarding.
Safety Relays
In the event of a hazard, safety relays can help reduce the risk to a more acceptable level. They are commonly designed to be used in conjunction with other safety relays to increase the functionality and safety levels in work environments. The design and functionality of these relays is similar to regular relays, with a few exceptions. Like a common relay, safety relays use contacts that can be opened or closed. However, they also have the ability to evaluate and then control outputs based on those evaluations. If installed correctly, a safety relay will continue to function if a fault in a device occurs or if a fault is caused by a sensor. The redundant design features of safety relays allow for wiring errors, while still providing proper safety function.
It is very common to see safety relays being used around industrial machinery where safety is critical. Areas such as an industrial manufacturing plant environment, where there are a lot of motors, machinery and conveyors all operating simultaneously. Some of the devices that safety relays will be used with are emergency stops, three position devices, safety gates, pressure sensitive mats, contact strips, foot operated switches and time delay scenarios. Safety relays are tested much more vigorously than normal relays and have a much lower failure rate. The contacts are designed so that they can be completely disconnected, breaking both sides of the power connection as opposed to just one, like many normal relays.