Abstract: A distributed modular input/output system includes a primary wireless device adapted to be operatively connected to an associated industrial controller. A secondary wireless device is physically disconnected from the primary wireless device. The secondary wireless device is operatively connected to the primary wireless device by a primary wireless backplane link. At least one input/output module is operatively connected the secondary wireless device. An associated field device can be connected to the at least one input/output module for communication with the associated industrial controller via the secondary wireless device, the primary wireless backplane link, and the primary wireless device. Typically, a plurality of the secondary wireless devices are physically disconnected from the primary wireless device and each includes one or more of the input/output modules operably connected thereto.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A redundant local area network uses two cables over which duplicate information is transmitted in parallel in the form of identical message frames. Each receiver on the network includes a circuit which evaluates the signals from the two cables and selects one of the signals to be processed. This circuit determines the length of the message frames received on each cable for a given transmission and indicates which cable, if any, carried the longer frame. The signal from the cable that carried the longer frame is then selected as the output of the receiver. Additional circuitry is provided to prevent two short frames on one cable from being considered as one long frame. An apparatus is provided to look at the historical reliability of the signals on the cables so that if one cable has had a significantly better performance than the other, a single poor transmission on the one cable will not cause the historically poorer cable to be selected until such time as the poorer cable has redeemed itself.