Chapter 14, Problem 35RQ

Program Plan Intro

Access method:

• The bus topology network needs some controlling techniques for access of particular devices to the bus.
• For transmitting information, a Programmable Logic Controller (PLC) will access the network by using access method.
• The most common access methods include token passing, collision detection, and polling.

DH+:

• The Allen-Bradley Data highway networks mainly have two communication network products such as Data Highway plus (DH+) and DH-485.
• DH+ makes use of peer-to-peer network in which a data communication system is formed by integrating programmable controllers and computers together.
• DH+ refers to a local area network that is used for factory-floor applications.