Posted By Robert Woods My experience is that red means a motor or process is running and green means it's not. Many production systems also work on the traffic light system green safe amber [normally with an accompanying siren] beware the process/line is about to start and red danger the lines running. If the emergency stop was activated the red light would flash and the siren would sound. Mayhem would then ensue as production managers would rush to see why production had stopped and first aiders and safety reps would fly to the scene to find any casualties. Don't forget that there should be a lock off systen in place rather than trusting the lights the right colour [apologies if this sounds patronising but you never know].

Posted By Jay Joshi It can depend upon what you are referring to--Is it a conventional mimic process panel in a control room or is it a central electrical motor control centre or is it a computer based integrated DCS-PLC sytem etc. There is an HSE Contract Research Report; no. 166/1998 "The management of alarm systems" that may have some information. Use the website link below to access the report http://www.hse.gov.uk/re...rr_pdf/1998/crr98166.pdf