ELECTRONIC SAFETY SENSORS

In contrast to category 2 electromechanical safety switches, which require a physical contact position for safety door monitoring, contactless safety switches employ contactless detection. This technology is particularly suitable for environments with high levels of dirt or dust and in areas that require strict hygiene regulations, such as food processing. These safety sensors, which are available in both electronic and magnetic form, consist of a sensor and a target that interact with each other without direct contact. As soon as the target is detected by the sensor, the safety door is securely closed and machine operation can be started safely. Electromechanical safety sensors in the CSS and RSS series are characterised by high tolerance in the case of door shifting and enable the transfer of essential diagnosis data as well as simplified evaluation of safety signals. Another advantage of these sensors is the improved protection against tampering thanks to specific coding.

ELECTRONIC SAFETY SENSORS CSS

Sensors in the CSS series use the Schmersal-developed Coded Safety Sensor technology (CSS), which is based on the pulse-echo principle. This enables a particularly rapid response. Microprocessor technology allows as many as 31 safety sensors to be daisy chained for activation via a common signal line. The evaluation takes place via a single safety relay module.

SAFETY SENSORS RSS

In developing the RSS series, the Schmersal Group's developers were successful in adapting the common RFID technology for use in safety applications. For example, the user can choose from three different types of coding:

• Basic version: The sensor accepts any suitable target.
• Coded version that only reacts to an individually assigned target. The teach-in process can be repeated as often as required.
• In a third variant, only the target taught in when the device is first switched on is accepted.

Comprehensive information on the construction forms and equipment of the CSS and RSS series safety sensors can be found in the extensive online catalogue.

MAGNETIC SAFETY SENSORS

Unlike category 2 electromechanical safety switches, safety sensors enable contactless position monitoring of safety doors. This is an advantage for machines that are exposed to high levels of dirt and dust. The sensors are also frequently used in hygiene-sensitive areas, such as the food industry. A basic distinction must be made between electronic and magnetic safety sensors. What both have in common, however, is that they each have a sensor and a target that communicate with each other without contact. The machine can then be put into operation when the sensor detects the target and the safety door and safety circuit are closed.

MAGNETIC SAFETY SENSORS OF THE BNS SERIES

The safety solenoid switches of the BNS-series use the proven principle of safe magnet technology. The switching devices are electromagnetic, non-contact and operate on two channels. As they have two safety contact paths, they are also fail-safe. The sensor can only be actuated with the corresponding target, but not with a conventional magnet, which is due to the combination and arrangement of the reed tubes in the sensor. This ensures a high level of protection against tampering. Despite their compact design, the BNS sensors achieve high switching distances. Concealed mounting is also possible, as the sensor technology works through plastic and even stainless steel covers.

DIFFERENT DESIGNS OF MAGNETIC SAFETY SENSORS IN THE ONLINE CATALOGUE

Schmersal offers the user a wide range of different designs, including sensors with stainless steel housings. All of the Schmersal Group's safety sensors have IP65 degree of protection at a minimum, are dust-tight and protected against water jets from all directions. When used in conjunction with a corresponding safety relay module, they can also achieve Performance Level d or e in accordance with EN ISO 13849-1. In its comprehensive online catalogue, the Schmersal Group provides detailed product information on the individual magnetic safety sensors.