The Ringline 2 Intrinsically Safe system is a line-powered monitoring and control system primarily designed for the fail-safe distributed emergency stopping and control of long conveyors. The system provides dual (redundant) electrical Safety Outputs that are controlled by the dual-channel status of a nominated combination of safety devices e.g. lanyard switches, stop switches, tracking switches, temperature switches, chute probes etc, which are the system inputs. The dual-channel status of each safety device is encoded onto the Ringline field bus (two-wire) via field transmitters (see Fig. 2) for reception by the Safety Function Card/s. The field bus circuit is fully down-line powered, can be up to 12km long and can interlock 96 or more safety devices to the Safety Outputs.