Introduction to Industrial Automation

8.3.5   The Actuator-Sensor Interface (AS-I) Network

In an industrial process, all actuators and sensors should be connected to the programmable auto-

mation system. The industrial network AS-I that first appeared in 1993 and was reissued in 2000 

supports communication at this level, known as machine level. Figure 8.10 shows a typical con-

figuration of the industrial network AS-I. At the machine level, where there is a large number of 

sensors and actuators, the installation and use of the AS-I network allows us to avoid the numer-

ous wiring that is replaced with a two-conductor cable for power and data transfer simultaneously, 

as shown in Figure 8.11a. The special cable of the AS-I network is depicted in Figure 8.11b, and 

is known as the yellow cable, and the applied technique of connection without removing the 

insulation make the wiring work simple, while providing greater security in the data transmis-

sion. In the same figure, it can also be observed that nowadays it is possible to interconnect even 

simple push buttons, something that was impossible as a non-supported feature a few years ago. 

The topologies that can be configured to implement the AS-I network are the bus, star, ring, and 

Figure 8.10  Interconnection of PLCs, sensors, and actuators through the AS-I network (Siemens).

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  Introduction to Industrial Automation

tree. Furthermore, the AS-I network has the ability to communicate easily with other industrial 

networks like DeviceNet, Profibus, etc.