How to Extend I/O Capability with Ethernet Application Note
Model 353 Controllers: Extending I/O Capability with Ethernet
Ethernet has gained wide acceptance in the industrial process control world as a viable local area network (LAN) solution. Today, Ethernet is also finding use on the sensor and data acquisition side of the controller. Manufactures have developed I/O devices that put thermocouple, RTD, current, voltage, and discrete I/O signals directly on Ethernet. Ethernet, then, can be used to acquire sensor information from remote locations extending the I/O capability of controllers.
This paper describes the Ethernet I/O that is available from Siemens and provides an overview on the use of this I/O with Siemens’ Model 353 Process Automation Controllers. References to detailed information on the various products mentioned are also provided. A detailed discussion of the use of Ethernet, and its use as a peer to peer network with Model 353 controllers, is provided in AD353-113. The current revision of this paper, along with others addressing related topics, can be found on the Siemens Website www.usa.siemens.com/ia, then click Process Instrumentation and then Process Controllers and Recorders; for this publication, type AD353-114 in the Site Explorer box and click Search.
There are a number of ways Ethernet I/O is used. In a simple implementation, it extends the I/O of a single panel-board controller; see Figure 1. A more advanced application might be to network multiple controllers located in various locations within a plant. In critical applications, various fault tolerant network configurations can be used to minimize the system affected by a failure of a network component or a network cable. Refer to the section on Switches for more information.