Data Acquisition and Signal Processing for Smart Sensors

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MULTICHANNEL INTELLIGENT AND VIRTUAL SENSOR SYSTEMS

In most measuring and control systems, a large number of sensors is connected to a central computer or a microcontroller. The number of frequency–time-domain sensors is continuously increasing in different applications of sensor networks. However, the software interface from the frequency–time domain to the digital domain can be a complicated design problem.

8.1 One-Channel Sensor Interfacing

A sensor network with multilayer architecture, for example, as shown in Figure 8.1, is widely used in systems with distributed intelligence like a modern car. The advantage of such an architecture is that high layers use the information from lower layers and do not press in detail of the operation of lower layers [144,145]. This proposed architecture realizes some interfacing functions. First, it is a low-level hardware and software interface (sensor–microcontroller), secondly, it is a high-level controller area network (CAN) interface that has been developed for automotive applications to replace the complex cable in cars by a two-wire interface [144].

Some sensors with frequency output can be placed in a high impedance state when not required. This is useful for applications where input devices share a microcontroller. As a rule, outputs are microcontroller compatible and designed to drive a standard TTL or CMOS logic input over a short distance. If lines are greater than 30 cm, then it is recommended that a shielded cable is used between ...