Display station having universal module for interface with different single loop controllers

Claim 1

In an industrial process control system for use with complex processes having a number of conditions the values of which are sensed to produce measurement signals used to develop corresponding control signals for elements such as valves and the like; each combination of measured value and corresponding signal defining a process control loop, each loop including an individual analog controller arranged to compare the measurement signal with a preselected set point signal and to produce a corresponding control signal responsive to the difference between the measurement and set point signals; said analog controller being any one of a number of different functional types, such as for primary analog control or cascade control and the like, according to the particular process control requirement of each loop; each loop further including signal display means to present visual indications of selected operational information such as measurement signal or control signal levels; apparatus providing improved means cooperable with any selected analog controller of said different functional types comprising: (1) a display station remotely positioned from said selected analog controller and having a front panel with signal-controllable display means arranged to present to an operator a visual image indicating the value of at least one analog signal level respecting a single corresponding process control loop; (2) transmission circuit means providing a number of individual signal circuits, said transmission circuit means connecting said display station with said selected analog controller and providing for transmission therebetween in both directions; (3) universal module circuit means located at said display station and coupled to said transmission circuit means, said universal module circuit means comprising logic circuit means to receive information signals from said selected analog controller and to control the operation of said display means to present a visual indication of at least one of said received information signals, said logic circuits means including a plurality of sets of signal paths for effectuating display control operations respecting each of said different functional types; (4) manually-shiftable selector means coupled to said logic circuit means and operable to condition said logic circuit means into any one of a number of different operating modes by selectively actuating predetermined ones from said sets of signal paths, each one of such different operating modes providing correspondingly different display arrangements for preselected information signals to conform with the type of analog controller coupled to the other end of said transmission circuit means; and (5) said logic circuit means being conditioned by said selector means into a dedicated operating mode to control said display means to provide for the display of the particular analog signals delivered by said selected controller in accordance with the type of said analog controller.