CURRENT LOOP INPUT PROTECTION Russian patent published in 2018 - IPC G05B19/42 H02J3/00 H02H9/04 

FIELD: electrical equipment.

SUBSTANCE: invention relates to electrical equipment. Protective circuit contains: a current loop input operable to receive a current proportional to a device reading; an operating voltage input, which is separate from said current loop input and is configured to couple to a voltage source and to receive from the voltage source a primary voltage signal, the operating voltage input further operable to power the component such that the process control device operates to control a process according to the device reading; and a plurality of protective circuit components. Protective circuit components are configured to: provide a secondary voltage signal to the components from the current loop input when the primary voltage signal is below a first threshold, and provide the primary voltage signal to the components from the operating voltage input when the primary voltage signal is above the first threshold.

EFFECT: technical result is enabling an analogue current loop to provide a device component with a secondary operating voltage received from an analogue current loop in the absence of a primary operating voltage source.

15 cl, 5 dwg