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IN 4000 – inductive door and position monitoring in the highest safety category
Waldkirch, April 2005 – The IN 4000 inductive safety system is a friction-free, vibration-proof, installation-friendly and contamination-immune solution for safe door or position monitoring in harsh industrial environments. The entire system, as well as the two individual sensor and relay evaluation unit components, are certified for Category 4 use in compliance with EN 954-1. The sensor of the IN 4000 can also be operated without an evaluation unit, in this case being directly connected to a safe PLC. A further highlight: wherever mechanical safety position switches have been used in the past (such as for the axial or radial monitoring of robots), the new system offers the possibility, for the first time, of reliable non-contact position detection without any actuator.

In the process, the cuboid sensor reacts to the presence or absence of metal, though only within a very specific range which is dependent on the material used. With St 37 steel, for example, the permissible switching range is from 10 to 15 mm. The switching range of the sensor is monitored in terms of both time and space. Unauthorised changes are detected and lead to safe switching off of the machine. Simple mounting and adjustment, as well as enhanced immunity to impacts and vibrations, are further advantages of the IN 4000.

Direct PLC connection possible

If the machine or plant to be protected 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 comply with EN 61131-2 and are thus compatible with the I/O signals of a safe PLC. Control Category 4 in line with EN 954-1 is maintained even when 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, up to ten sensors can be connected – leading to considerable cost savings, particularly in the case of complex machines or plants. Three safety-relevant N.O. contacts, two N.C. relays, and integrated external relay monitoring also allow flexible integration in the particular machine controller.

By doing without a separate actuator, with direct connection to a safe PLC, the IN 4000 offers completely new approaches to safe position determination and the monitoring of protective doors on machines and plant.