Understanding Smart Sensors - Nomads.usp

284 Understanding Smart Sensors• Triggering buffered sensors;• Triggering data sequence sensors;• Triggering buffered data sequence sensor;• Triggering event sequence sensors.When the sensor STIM reacts to an NCAP trigger, the transducer beginsreading [7]. When the reading is complete, the STIM makes a trigger acknowledgeand the NCAP reads the value(s). The actuator STIM reacts to an NCAPtrigger by writing the value(s) and initiating transducer actuation. When complete,the STIM asserts a trigger acknowledge.Triggering the buffered sensor results in the same response as the standardsensor except the value is returned from the previous trigger. That means it isan immediate response, but the time of the reading is uncertain [7].A data sequence sensor samples at its choice of time, typically synchronizedwith the physical world. After the trigger, the sensor waits until the nextsample time and then returns an ACK signal and the results [7].Triggering the buffered data sequence sensor is similar to triggering thedata sequence sensor, except that it makes the data in the holding buffer available.The trigger acknowledgment is coincident with the availability of the previouslyacquired data set. If another trigger occurs after the holding bufferis read but before the acquisition of the next sample of data is complete, theacknowledge signal is not returned until the data acquisition process iscomplete [6].An event sequence sensor is the same as the data sequence sensor, but itdoes not return any data. For this sensor, the time of the event is the relevantinformation [6].12.4.2 Transducer Electronic Data SheetThe TEDS identifies essentially everything you wanted to know or may wantto know about the transducer, including:• Manufacturer, model number, revision code, serial number, devicetype, and date code for transducers;• When the unit was calibrated, the variable, type, and limits of use;• Calibration constants;• Signal conversion data model, model length, and number of significantbits;