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What is a sensor?

A sensor is a transducer that converts a physical, biological or chemical parameter into a electrical signal, for example: temperature, pressure, flow, or vibration sensor. Sensors also measure some physical parameter and return digital data representing that parameter to an NCAP.  

A sensor can also describe itself to the network, making it easier for automatic system configuration. It does this by the use of TEDs.The TEDs can be uploaded to the system upon power up or upon request. It also serves as documentation.  

What types of sensors are defined in IEEE 1451.2?

  • Sensor: Takes a new sample with each trigger.
  • Buffered Sensor: Behaves like a sensor, but makes the data acquired on the previous trigger available for immediate reading.
  • Data Sequence Sensor: Acquires a sequence of measurements without missing a sample.
  • Buffered Data Sequence Sensor: Keeps the most recent readings in its buffer so that it is always available to be read immediately after a trigger.
  • Event Sequence Sensor: Armed by the trigger and responds with an acknowledge signal when the event is detected.


What is an actuator?

An actuator is a transducer that accepts a signal and converts it to a physical action. In other words, an actuator causes an action to occur relating to the data that was sent to it by via an NCAP. Data written to an actuator is held in an input register until the trigger is received. An actuator can also describe itself to the network, making it easier for automatic system configuration. It does this by the use of TEDS. The TEDS can be uploaded to the system upon power up or request. It also serves as documentation. 


What is DAC?

DAC stands for Digital-to-Analog Converter. It is an electronic circuit that inputs a digital value and outputs a proportional analog signal. 


What is ADC?

ADC stands for Analog to Digital converter. It is an electronic circuit that accepts an analog input signal and outputs a proportional digital signal. For IEEE 1451.2, an onboard analog to digital conversion circuitry converts the analog voltage levels of transducers to the digital representation used by the node applications. 


What is DI?

D I stands for Digital Input. DI is used to input binary-state (low or "zero" state and high or "one" state) signals by sensing switch closure or light beam breaks. For example, for positive logic, a zero-volt input is equivalent to an low input, and a five-volt input is equivalent to a high input. 


What is DO?

Digital Output (DO) is used to output binary-state(low or "zero" state and high or "one" state) signals to actuate devices such as relays and solenoids.

What is address logic?

Address Logic is a character or group of characters that identifies a register, a particular part of storage or some other data source of destination. IEEE 1451.2 uses functional addresses and channel addresses to control the flow of data and configuration information between the NCAP and the STIM. For example, address logic can be implemented by a discrete circuitry, ASIC (application specific integrated circuit), or microprocessor.

Created October 6, 2009, Updated June 2, 2021