Diagnostic element for validation of bolt detection of a guard locking switch in a static state

A system for sensing a position of a locking bolt of an industrial locking switch, comprising:

• an inductive circuit comprising an inductive coil and a capacitor electrically connected in parallel, wherein the inductive coil is positioned to receive a locking bolt of an industrial locking switch when the locking bolt is transitioned to a lock position;
• a converter configured to convert a frequency of a current signal on the inductive circuit to a digital frequency value;
• and
• a master controller configured to generate a bolt detection signal in response to determining that the digital frequency value changes by an amount equal to or substantially equal to a defined frequency shift corresponding to a frequency shift induced by the inductive coil in response to presence of the locking bolt within the inductive coil's magnetic field;
• wherein the inductive coil is mounted in a central opening of a bobbin mounted inside a housing of the locking switch;
• and
• an RFID coil is mounted on a top surface of the bobbin that is slanted relative to a bottom surface of the bobbin, and the top surface tilts the at least one RFID coil relative to the inductive coil.

A method for detecting positions of a locking tongue of a locking switch, comprising:

• one or more entry slots configured to receive a locking tongue;
• a radio frequency identifier (RFID) tag attached to the locking tongue;
• generating a current signal through an inductive sensing circuit attached to one of the one or more entry slots, in response to detecting that a locking tongue is advanced to a locking position, wherein the inductive sensing circuit comprises an inductive coil and a capacitor;
• converting a frequency of the current signal to a digital frequency value;
• determining whether a shift in the digital frequency value corresponds to an expected frequency shift of the current signal induced by the inductive coil in response to advancement of the locking tongue;
• and
• generating a lock detection signal in response to determining that the shift in the digital frequency value corresponds to the expected frequency shift of the current signal;
• further comprising a locking bolt configured to engage with the locking tongue when advanced to a locking position;
• and
• a control circuity configured to receive the detection signal and determine a position of locking bolt based at least in part on the detection signal.