INTRINSICALLY SAFE COMMUNICATIONS CIRCUIT

摘要

An electrical circuit comprising a power supply, a load, a pair of parallel positive cables between the power supply and the load, a pair of parallel negative cables between the load and the power supply, and incendive arc prevention means, comprising : monitoring means adapted to detect if the current and/or voltage in one of the pair of cables deviates from the other, and a control means adapted to fully or partially isolate the power supply from the pair of cables if the monitoring means detects that their current and/or voltage has deviated from the other, characterised in which: the electrical circuit comprises a common positive section between the power supply and the pair of positive cables, and a common negative section between the pair of negative cables and the power supply, in which a first modulation means is adapted to generate a modulated communications signal.