Abstract: An input/output (I/O) and control system for long distance communications and industrial applications having a bus and 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 of configurable frequency 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. Changing the synchronization pulse length increases bandwidth for shorter, less noisy and more stable systems and inversely decreases bandwidth for increased noise immunity and distance for longer, noisier and less stable systems.

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 having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces a pulse train such as an offset square wave with dual scan bus cycles having alternating A and B scan cycles that each comprise a plurality of channel windows assigned to the field devices. One or more channel windows in the A and B scan cycles has an exception interrupt window during which the control unit can detect a low level signal provided by a field device before its corresponding channel window in the dual scan bus cycle, thereby reducing system reaction time.

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 having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces a pulse train such as an offset square wave with dual scan bus cycles having alternating A and B scan cycles that each comprise a plurality of channel windows assigned to the field devices. One or more channel windows in the A and B scan cycles has an exception interrupt window during which the control unit can detect a low level signal provided by a field device before its corresponding channel window in the dual scan bus cycle, thereby reducing system reaction time.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces a pulse train such as an offset square wave with dual scan bus cycles having alternating A and B scan cycles that each comprise a plurality of channel windows assigned to the field devices. One or more channel windows in the A and B scan cycles has an exception interrupt window during which the control unit can detect a low level signal provided by a field device before its corresponding channel window in the dual scan bus cycle, thereby reducing system reaction time.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications having a bus and protocol for communications between field devices and a channel generator for monitoring and control of the field devices. The channel generator produces a pulse train such as an offset square wave with dual scan bus cycles having alternating A and B scan cycles that each comprise a plurality of channel windows assigned to the field devices. One or more channel windows in the A and B scan cycles has an exception interrupt window during which the control unit can detect a low level signal provided by a field device before its corresponding channel window in the dual scan bus cycle, thereby reducing system reaction time.

Abstract: An input/output (I/O) and control system for long distance communications and industrial applications having a bus and 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 of configurable frequency 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. Changing the synchronization pulse length increases bandwidth for shorter, less noisy and more stable systems and inversely decreases bandwidth for increased noise immunity and distance for longer, noisier and less stable systems.