Interlocking devices associated with safety guards

NF EN ISO 14119 provides measures restricting the possibility of reasonably foreseeable fraudulent neutralization on locking devices. Some drawbacks The key does not provide inviolability. This system has problems related to minimum radius, alignment and breakage when operating the key. The switch often has only one door position contact and two locking contacts. For maximum performance level PL = e, a position sensor must be added with redundant outputs. This overburdens the wiring, occupying 4 inputs on a safety PLC.