Allen-Bradley is the brand-name of a line of Factory Automation Equipment manufactured by Rockwell Automation (NYSE ROK). The company, with revenues of approximately US$4.5 billion in 2006, manufactures programmable logic controllers (PLC), human-machine interfaces, sensors, safety components and systems, software, drives and drive systems, contactors, motor control centers, and systems made of these and similar products. Rockwell Automation also provides asset management services including repair and consulting. Rockwell Automation's headquarters is based in Milwaukee, Wisconsin.
The Allen-Bradley Clock Tower is a Milwaukee landmark featuring the largest four-sided clock in the western hemisphere.
The company was initially founded as the Compression Rheostat Company by Dr. Stanton Allen and Lynde Bradley with an initial investment of $1,000 in 1903. In 1910 the company was renamed the Allen-Bradley Company. In 1952 they opened a subsidiary in Galt, Ontario, Canada, that now employs over 1000 people. In 1985 a new company record was set as they ended the fiscal year with 1 billion dollars in sales. On February 20, 1985, Rockwell International (now Rockwell Automation) purchased Allen-Bradley for $1.651 billion, which is the largest acquisition in Wisconsin's history.
Allen-Bradley is the same name associated with low temperature sensors, since a now obsolete line of carbon-composite resistors manufactured by Allen-Bradley show an approximately inversely proportional temperature dependence at low temperatures. This undesirable characteristic for commercial resistors (since an ideal resistor should have no temperature dependence) is suited for cryogenic measurement, which paradoxically has partly helped establish a name for Allen-Bradley among the lay electronics enthusiast. Allen-Bradley resistors are commercially available at a premium, often supplied with calibration data.