Control Device 1 : A device connected into the control circuit and used for controlling the operation of the machine (e. g. , position sensor, manual control switch, relay, magnetically operated valve)
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}