Each device is allocated a fixed time at which {HEAD ~ its input and diagnosis data} is transmitted as data frames to {TAIL ~ the controller} 200 
Each device is allocated a fixed time at which { HEAD ~ its input and diagnosis data } is transmitted as data frames to { TAIL ~ the controller } 200
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH