graphic panel[¦graf·ik ′pan·əl]
an arbitrary representation of an object being controlled by means of symbols and indicators arranged on the front of a control panel or on special panels in front of a controller’s console. It shows graphically the condition (status) of an object or the progress of a production process. The equipment and internal linkages of the object are depicted according to conventional notations for electrical, technological, transportation, and other diagrams. The status of the process being controlled is automatically represented on the panel by signaling devices.
A graphic panel is a simplified model of an object that makes it easier to remember its structure and the functions of the various instruments, equipment, and control members, and also the modes of operation under various operating conditions. Such panels are used in cases where an object has a complicated structure, where a production process is controlled according to a large number of parameters, and where the rapidly changing condition of an object requires operational control that in many cases is difficult and even impossible to perform from memory. They are also used as demonstration models at technical exhibitions and as educational aids, on which the arrangement and sequence of the application and removal of load, the flow of raw materials and finished products, the movement of traffic, and the functional relations and operating rhythm of individual parts and elements of the simulated object are indicated graphically.
Graphic panels are subdivided into operator and dispatcher types, which differ in the complexity and scale of the objects represented (in the first case the object is usually a concentrated technological system; in the second, it is spread over an area and is composed of many objects and technical systems), in the detail of representation of the individual objects, and in the presence of built-in control members in operator panels. In addition, a distinction is made among mimic, luminous, and combination (semiluminous) types, according to the principle of operation and technology of production.
On a mimic graphic panel the conventional notations and connecting lines are painted on or laid out in colored markers. The individual devices and objects represented have signal lamps next to them, usually in two colors: red, which indicates that the circuit, machine, or apparatus is operating, and green, which indicates that it is not. A change in the status of an object being monitored may also be shown by means of various mechanical indicators, such as the deflection of a pointer, the displacement of a marker, or the rotation of disks with colored sectors on them. Mimic panels are used mainly in cases where the nature of a production process is such that the mere indication of a change in the condition or status of an object is sufficient (for example, indication of “open” or “closed” for a damper or “current” or “no current” in a circuit)—that is, where the control information is discrete in nature.
The graphic potential is much greater in the case of luminous panels, in which information about the condition of the object being controlled is depicted by a change in the color or brightness of the elements on the panel, by a displacement of a spot of light, by the nonuniform intensity of illumination of the sections (lines or sectors) of the panel, or by a change in the configuration or dimensions of a spot of light. Such panels also include electroluminescent and projection panels (including motion-picture and television types). The use of advances in optoelectronics and elements of fiber optics for such panels is promising.
On combination panels, only the main elements are illuminated; other parts are done in paint or markers, as on mimic panels.
The choice of a type of panel depends on the structure of the control system and the nature of the production processes, on the functional diagram, and on the purpose and degree of automation of the object being controlled. A graphic panel is frequently combined with measuring instruments and devices, thus improving conditions for observation of the object and increasing the quantity and quality of the information on the panel.