Protection against tampering still is a theme of machine safety. This applies since the moment that a BGIA review has revealed that in approximately one third of 1000 inquired companies the safety devices on machinery and plants are being tampered.

The best protection against tampering undoubtedly is offered, when the safety devices are optimally integrated in the production processes or the machine. If this condition is met, the operator will not be tempted to tamper.

Precautions however can also be taken at device level. To this end, mechanical safety switches with individually coded actuators can be used for instance. The safety sensors with non-contact operating principle also are available in versions with coded magnets, in which the sensor for instance does not react onto conventional magnets. And for the CSS technology developed from Schmersal, a version is now available, in which the sensor and the target have a paired coding.

This paired coding avoids that a sensor reacts onto the actuator of another CSS sensor. The technical realisation hereof is a little bit more challenging than with conventional magnetic safety sensors, considering that the basic principle of the CSS technology consists of a bidirectional communication between the sensor and the target.

But the Schmersal engineers found an elegant solution to this problem and the result of their efforts is presented at the Hanover Fair: the CSP 34 safety sensor. The CSP 34 offers the same advantages as its well-known family member, the CSS 34: its cubic section enables a smooth fitting onto conventional profile systems. Up to 31 safety sensors can be wired in series and monitored through a common safety module in accordance with control category 4 and up to SIL 3 or Performance Level “e”. The devices do not only tolerate a large guard door misalignment; they even detect this misalignment and emit a warning, so that the operator can realign the guard door, before the machine detects an error in the safety circuit and shuts down.