SICK has released the inductive IN 4000 safety system. It is friction-free, immune to vibrations, easy to install and unaffected by dirt, allowing reliable monitoring of position or protective doors in harsh industrial environments.
The system and its individual sensor and relay evaluation units are certified for Category 4 use according to EN 954-1. The sensor can also be connected directly to a safe PLC. The basic version of the IN 4000 consists of an inductive sensor in a cubic housing and a relay evaluation unit. The noncontact operation of this inductive safety system provides the advantages of simple installation and adjustment, as well as increased immunity to impacts and vibrations.
If the machine or plant to be safeguarded is controlled by a safe PLC the IN 4000 sensor can be run directly on it. This is possible because the sensor's input and output signals are designed to correspond to EN 61131-2 and are therefore compatible with the I/O signals of a safe PLC. Control Category 4 according to EN 954-1 is maintained even if the maximum number of 10 sensors is connected in series. If there is no safe PLC available the sensor is connected to the IN 4000 evaluation unit with relay outputs. Here too the connection of up to ten sensors is possible. This leads to considerable cost savings, particularly in the case of complex machines or plants. Three safety-relevant NO contacts, two NC relays and integrated external relay monitoring also allow flexible integration in a machine control system.
The inductive operation principle requires no separately coded actuator. The sensor directly detects the presence or absence of metal. The switching area of the sensor is monitored in terms of both time and space to provide the necessary prevention of simple tampering. Unauthorised alterations are detected and lead to the machine being safely switched off.