Front panel for a process controller

In an industrial process electronic controller operable in a manual or automatic mode to compare a signal representing a process variable with a set point signal to produce an output signal that reflects the deviation of the variable from the set point, the output signal being applied to a final control element for governing the process variable, a front display panel free of discrete indicators or switches comprising:

• A. a first gas discharge bar graph analog indicator responsive to the process variable signal;
• B. a second gas discharge bar graph analog indicator responsive to the set point signal;
• C. a third gas discharge bar graph analog indicator responsive to the output signal;
• and
• D. a gas discharge digital indicator responsive to the signal applied to either the first or second indicator, said analog and digital indicators being integrated in a display panel constituted by a non-deflectable front plate spaced a fixed distance from a parallel second plate and peripherally sealed thereto to define a sealed envelope filled with an ionizable gas, said plates having electrodes formed on the internal surfaces thereof appropriate to said first and second analog and said digital indicators whereby all of the analog and digital indications appear and are readable on said common panel, said first and second indicators being vertically disposed on said panel in parallel relation adjacent a graduated scale, said third indicator being horizontal and disposed below said first and second indicators, said display panel further including electrodes formed on the internal surfaces of said plates to define a plurality of touch-sensitive capacitive switches in which said gas functions as a dielectric, said switches each being actuated when the front plate in the region of the electrodes forming the switch is merely touched by an operator, one of said switches, when actuated, causing said controller to operate either in the manual or automatic mode, whereby all of said indicators and said switches are integrated into said sealed, gas-filled envelope which acts as the display panel which is free of discrete indicators or switches.