Abstract: An input/output (I/O) and control system for long distance communications and industrial applications is provided having a two wire bus and bus protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. High side and low side current detectors for respective ones of the two wires of the bus and an algorithm are provided to improve detection of valid inbound transmissions by the channel generator for increased noise immunity.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications is provided having a two wire bus and bus protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. High side and low side current detectors for respective ones of the two wires of the bus and an algorithm are provided to improve detection of valid inbound transmissions by the channel generator for increased noise immunity.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications is provided having a two wire bus and bus protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. High side and low side current detectors for respective ones of the two wires of the bus and an algorithm are provided to improve detection of valid inbound transmissions by the channel generator for increased noise immunity.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications is provided having a two wire bus and bus protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces an offset square wave on the bus, and sends a synchronization pulse of selected duration at the start of each bus scan cycle in a pulse train cycle to reset counters in the field devices before the bus scan cycle is repeated, to ensure field devices are synchronized, transmitters transmit on the correct channel, and receivers sample the pulse cycle at the correct time. High side and low side current detectors for respective ones of the two wires of the bus and an algorithm are provided to improve detection of valid inbound transmissions by the channel generator for increased noise immunity.