Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.

Programmable Logic Controllers 17 as being of relay type, transistor type, or triac type. The communications interface is used to receive and transmit data on communications networks from or to other remote PLCs. There are two common types of mechanical design for PLC systems--a single box and the modular/rack types. The IEC 61131 defined the standards for PLCs, with 61131-3 defining the programming languages: ladder diagrams (LAD), instruction list (IL), sequential function charts (SFC), structured text (ST), and function block diagrams (FBD). Problems Questions 1 through 6 have four answer options: A, B, C or D. Choose the correct answer from the answer options. 1. The term PLC stands for: A. Personal logic computer B. Programmable local computer C. Personal logic controller D. Programmable logic controller