Safety Sensors
Safety sensors are used to prevent accidents in factories, warehouses and other industrial facilities. They detect the presence of people and can also trigger other safety mechanisms.
Examples include a hinged or sliding guard switch that disconnects power as soon as it is opened and speed and separation monitoring for collaborative robots, which helps reduce risk without decreasing performance.
Detection
Safety sensors are installed in doors, machine casings and gates to prevent unauthorized access to hazardous parts of the machinery. When someone attempts to open these protective structures, the sensors detect the action and trigger an interlock function that stops the dangerous machine.
Various types of safety sensors are available to match the specific needs of machines and plant layouts. Each safety sensor has a different sensing range and detection method. The sensor’s type is determined by a risk assessment, in which the potential risks and their consequences are evaluated. The safety level required for each machine is then established.
The most common reasons for safety sensor malfunction include dirty lenses, misalignment and pinched wires. The photo eye lenses in safety sensors are very small and are susceptible to contamination. Regular cleaning with a soft cloth and mild cleaner can prevent the buildup of dust and other residue that may cause a failure to operate.
In addition to the standard single thru-beam photoelectric sensors, the HE series is also available in an ATEX variant and with OSSD contacts that enable a daisy chain of up to 30 switches. These safety OEM sensors are ideal for modular machine systems and offer a high resistance to vibration and a status LED. For hygienic applications, the HE switches are available with an Ecolab certified coating and can be used in damp or wash down environments.
Warning
Safety sensors warn users when protective devices or machine casings are open and thereby expose them to danger. Depending on their safety level, they can give an emergency signal or stop the machine completely. The type of sensor that is used primarily depends on the results of a risk assessment carried out by machine manufacturers.
For example, garage door sensors warn drivers when a closing garage door is about to hit their cars or people and animals. They also prevent injuries and even deaths caused by the doors when they move into the path of humans and pets.
A quick test for these sensors in your garage is to cover the sensor lights with large-sized cardboard boxes and try to close the door. The sensors should react instantaneously and start reversing the motion of the garage door. If this is not working, call a technician for realignment of the sensor system.
Alerting
Safety sensors can be triggered by different events, depending on their design and purpose. Door and window alarms, for instance, can alert you when someone opens a locked door. Some can also be integrated into a home security system to provide remote monitoring and call for help in the case of an emergency. Other safety sensors can detect carbon monoxide, a poisonous gas that is often undetected and can be lethal in large concentrations. Carbon monoxide detectors can trigger warning lights or an alarm in the event of a CO leak.
For industrial applications, safety sensor switches can be used to monitor the position of guards or other barriers to ensure equipment is in a safe operating state. These devices utilize two mounted sections that transmit an infrared beam between them to detect any obstructions or movement that may compromise the safety of an area. Several important factors influence the functionality of a safety sensor switch, including the positioning and height of the mounting section. Make sure the two sensors are properly aligned, and that they are at least 4 to 6 inches off the ground to avoid interference from floor-level objects.
In the event of an accident or injury, it is essential to respond quickly and effectively. Monitoring systems such as Blackline’s SafeGuard can reduce workplace accidents by analyzing real-time data to generate and relay critical insights that are made available on a range of end-user devices.
Control
A common use of safety sensors is to control gates and hatches around dangerous machines. This allows people to enter and work with the machine safely while ensuring that the machine cannot be started again.
Another use of safety sensors is speed and separation monitoring. This slows down the robot as a person gets closer in its workspace, which reduces the risk without reducing the performance of the robot. This is possible because the robot only has to stop when it detects a person, not when the entire area is detected by a sensor.
In addition to the detection functions of safety light curtains, the PSENopt muting function allows users to switch the output of a safety system OFF only when a human passes through a detection area. This allows production to continue while the danger zone is occupied.
This feature enables manufacturers to comply with the regulations regarding minimum distances between workers and industrial machinery. In addition, the PSENopt switches are ATEX-certified and therefore suitable for use in hazardous environments. They also have the option to be used in Ex zone 2 applications with the use of a protective casing or hygienic connection. The re-teachable contacts (OSSD) of the switch enable you to connect multiple sensors in a daisy chain without losing functionality. lone worker safety devices The switch is also available as a SIL 3 version to comply with the latest safety standards.
