Programmable Electronic System (PES) 1 : A system based on one or more central processing units (CPUs), connected to sensors or actuators, or both, for the purpose of control or monitoring
NFPA 79 Electrical Standard for Industrial Machinery, 2002 ed. http://www.nfpa.org/assets/files/AboutTheCodes/79/ 79-A2002-rop.pdf, (Electr Std for Ind Machinery - Amer) {225 NFC}