Summers pneumatic

Of course, there are many more possibilities than the examples shown. They just focus on the theme in general and may be helpful for the discussion of future building systems. Other examples of materials include pneumatic systems or even fibre-reinforced materials, hybrid materials that combine different elements for additional functions. In the future, for example, windows may be used not only to obtain daylight, but also as solar collectors, as media fagades, and as flexible fagades with different properties for summer and winter. 

Summers are devices that add or subtract. If pneumatic versions with adjustable gain are required, one should avoid those with pressure-dividing networks. Tlieir accuracy is poor. 

A convenient method for providing feedforward compensation that does not interfere with either norm reset or antireset windup involves the use of an impulse relay and a summer as shown in Figure 9.8. In pneumatics these fimctions are sometimes combined into a single device. The impulse function... 

To implement equation (11.1), we need a summer with adjustable gain and bias, and a multiplier. For the former the Foxboro 136-1 is a suitable devicct while for the latter we would use the Foxboro 556-8 multiplier. The discussion that follows, however, could be readily extended to other pneumatic, electronic, or digital devices. A commonly used hardware arrangement is shown in Figure 11.2. 

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