Petroleum Instrumentation NGT 160 Basics Instrumentation Chapter 12 Programmable Logic Controllers “This product was funded by a grant awarded by the U.S. Department of Labor’s Employment and Training Administration. The product was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership.” Unless otherwise specified, this work by ShaleNET U.S. is licensed under a Creative Commons Attribution 4.0 International License.

Programmable Logic Controllers (189) A PLC’s solid state electronic components, reliability ,and flexibility make it ideally suited for harsh industrial environments. Easily reprogrammed by a technician in the field. A computer is the heart of a PLC. Replaced old relay logic circuits Today more complex and powerful Can perform mathematical comparisons and multiply and divide and extract square roots. Perform proportional, integral, and derivative (PID) functions. Why it was named what it is named.

Programmable Logic Controllers (189) Common building blocks of a PLC.

Programmable Logic Controllers (190) Five major hardware components of a PLC.

Programmable Logic Controllers (191) Ladder logic diagram (Boolean logic or ladder logic)

Programmable Logic Controllers (190) Ladder logic diagram (Boolean logic or ladder logic)

Programmable Logic Controllers (192-195) Logic numbering systems Necessary for communication with computers Computers cannot handle decimal numbers Binary code developed – two states: on-off, etc. Octal and Hexadecimal numbers.

PLC Measurement Summary (205) Review Exercise (205)