A method implemented in a near-field communication system (100), for detecting the presence of a radio-frequency transponder (110) by means of a radio-frequency reader (120) on board a motor vehicle, said radio-frequency transponder (110) being carried in use by a user located outside the vehicle, and said radio-frequency reader (120) being intended to communicate with the radio-frequency transponder (110) so as to control access to the motor vehicle, the method comprising the following steps implemented by the radio-frequency reader: transmitting a radio-frequency interrogation signal; then transmitting a radio-frequency supply signal, intended to be received then modulated by the radio-frequency transponder; detecting the presence of the radio-frequency transponder (110) by measuring an amplitude of the radio-frequency supply signal and comparing it with at least one predetermined threshold.

An electronic key may include a partial capacitor comprising a capacitive metal plate in communication with a processor. The capacitive metal plate of the partial capacitor is configured to form a capacitor with a corresponding capacitive metal plate of a lock when brought into proximity with the metal plate of the lock. Data may be transferred from the key to the lock using a capacitor formed by combining the two metal plates, wherein a common ground is established between the metal plate of the key and the metal plate of the lock through a parasitic capacitance present between the key and lock circuitry. Audit trail data may be recorded based on usage of the key.

Lockout/tagout devices are configured to receive multi-user, electronically generated locking and unlocking commands over wireless interfaces to realize lockout safety chains of a desired length to assure worker safety in an industrial system. Electronically implemented systems and methods are also disclosed providing for enhanced worker safety, increased security, and improved lockout/tagout oversight involving a reduced number of locking devices and with fewer complications compared to conventional lockout/tagout devices, systems and processes.

Aspects of the disclosure relate to electronic access control. An access control server maintains data associated with a plurality of electronic locks. A user is issued an electronic key for unlocking one or more electronic locks. The user can be assigned to a group. Members of the group are permitted to access a subset of the plurality of electronic locks. A first key configuration is transmitted to the electronic key, the first key configuration permitting the user to access the subset of electronic locks. The access control server accesses personnel data related to the user and determines whether the personnel data satisfies a condition associated with the group. Responsive to determining that the condition is not satisfied, the user is removed from the group and a second key configuration is transmitted to the electronic key, the second key configuration preventing the user from accessing the subset of electronic locks.