Pneumatics Diagrams/Schematics

Before we look at more complex pneumatic circuits, we first need to look at the way these components are represented in a diagram. A pneumatic diagram shows how the components in a circuit are connected so that we can understand what the circuit does and how it works. In some cases, pneumatic diagrams can be shown as pictorials, where actual pictures are used. While pictorials allow us to see what the devices look like, they are very time consuming to draw and are actually harder to use.

To solve this problem, schematic diagrams are used. A schematic diagram is a form of visual shorthand where standard symbols represent each component. A schematic diagram shows all the components in a circuit and their interconnections. Except when noted, a schematic diagram shows all the components in their de-energized state.

Below are examples of a pictorial diagram and a schematic diagram.

Pictorial Diagram:

Schematic Diagram:

The Symbols

Both essentially say the same thing. As you learn about each new pneumatic component, you will learn the symbol for each device. Most symbols use an elementary form to identify the general function of the component. These forms are circles, squares, rectangles, triangles, arcs, arrows, and lines. These basic symbol forms are combined to form symbols of various components.

Below are the basic symbols. When combined, they can make different, more complex pneumatic components.

The 3 standards that are most often referenced for symbols are those developed by the National Fluid Power Association (N.F.P.A.), American National Standards Institute (A.N.S.I.), and the International Organization for Standardization (I.S.O.). Different industries demand that the machines and components that are used meet certain standards. All 3 standards can be found in the USA.

Look at the following schematic of a typical pneumatic system. Notice how we have combined the simple symbols to create more complex schematic symbols. Study the symbols from both the chart above and the following schematic. In the quizzes that follow, you will be asked to identify each symbol.

Note: As we go forward, we will use schematics to work on the Trainer Labs.

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