These leading firms , namely Asea Brown Boveri , The Siemens Corporation , Endress+Hauser Group , and The Emerson Fisher Division, represent key forces in the automation and process instrumentation landscape. https://nicolasildm563599.tinyblogging.com/the-abb-company-the-siemens-corporation-endress-hauser-emerson-fisher-controls-a-comparative-analysis-85987646