Shanghai Chenzhu Instrument CO., LTD.
Shanghai Chenzhu Instrument CO., LTD.

What You Need to Know About Safety Relays

Mar 23 , 2022

1. The status quo and development prospects of safety relay system

Safety relay system is used to reduce risk: in the event of a fault or intrusion into the detection area, the safety relay responds safely and reliably. Safety relays are used in almost every field of mechanical engineering, mainly because the number of safety functions is easy to control. However, there is an ongoing effort to integrate diagnostic information into the control concept and overall concept. Therefore, safety relays with communication interfaces will be more widely used in plants and machines in the future.

2. The necessary characteristics of safety relay users

Safety relays are clearly structured and easy to operate, so no special training is required. To use these devices successfully, users usually need some simple electrical basics and an understanding of current standards. Safety relays are compact, reliable and, more importantly, comply with all required standards, so they are used in a wide variety of applications. They have now become an essential element of any equipment or machine, ensuring that the safety functions in these installations work.

3. The safety relay working principle

The intrinsically safe relays has a forced-guided contact structure and is a necessary control part in a safety loop. It accepts safety input, and through the judgment of the internal loop, deterministically outputs the switch signal to the control loop of the device. Simply put, the safety relays are all dual-channel signal types. Only when the signals of both channels are normal, the safety relay can work normally; during the working process, as long as the signal of any one of the channels is disconnected, the safety relay will stop outputting until the two channels are disconnected. All channel signals are normal and can work normally after reset.

4. The function of the safety relay

Since the advent of the first safety relays, whose original purpose was to monitor emergency shutdown functions, numerous devices have been put into use. In addition to the monitoring function, it can also perform some very specific tasks: for example, monitoring the speed or checking whether the voltage on the mains contactor is disconnected. These devices are designed to work seamlessly with the sensors and actuators currently available on the market. Today, safety relays can meet almost all requirements. Safety relays vary in function and can implement almost all safety functions, such as monitoring the entire safety chain from sensors to evaluation logic to actuator activation.

5. Distinguish between different safety relays

Our safety relays mainly include: e stop relay button, safety gates input; light curtain safety relay input; two-hand button input; mat relay input; contact expansion module; and safety relays suitable for various SIS controllers.

6. Common functions and advantages of various safety relays

(1) There is no change in the basic requirements: that is, the safety relay must be designed in such a way that when the cables are connected correctly, neither equipment failure nor external failure caused by sensors or actuators will result in the loss of the safety function.

(2) Technological changes have promoted the development of electronic safety relays, bringing more benefits to customers: electronic equipment will not wear out and have diagnostic functions, which are easy to integrate into a common bus system for control and diagnostic purposes.