A smart sensor takes inputs from the physical environment and process the data using built-in compute resources and outputs processed data for further use.
What is a Sensor?
Sensor is a device which produces an electrical signal that is related to some physical quantity. Hence, a sensor will measure a physical quantity and this measurement will be displayed by using an instrument.
What is Smart Sensors?
These sensors are also called intelligent sensors, and they have integrated electronics which enable them to perform certain functions like logic functions, two-way communication, etc. Also, they are capable of making decisions. These sensors are also able to measure environmental data with more accuracy and less noise. These sensors are used to monitor and do the controlling mechanism in industries. Theese sensors have three important parts. They are:
- Sensing element
- Signal processing part
- Microprocessor
Difference between Smart Sensors and Conventional Sensors
- These sensors differ from the conventional sensors in a way that they are faster than the conventional type.
- These sensors are also more accurate than the conventional sensors.
- These sensors are smaller in size as compared to conventional sensor.
- They consume low power.
Functions of Smart Sensors
These sensors have the following functions:
- They are used for performing information processing.
- These sensors can perform compensation.
- They perform integration with other systems.
- These sensors perform validation.
- These sensors perform data fusion.
Reasons for use of smart sensors
These sensors are used because:
- These have the ability of self-calibration.
- The accuracy level is very high
- They have a relatively good communication.
- They can do multi-sensing.
- Cost-effective.
- Quick response.
- Low power consumption.
- They have a remote diagnosis.
Features of Smart Sensors
These sensors have the following features:
- Analog to digital conversion
- Microcontroller with advanced features, mostly PIC
- Sensor identification
- Data logging as well as real time clock
- Communication via serial bus
Selection Criteria for Smart sensors
Smart sensors are used based on the following criteria:
- They are selected accord to the self-calibration capability.
- The accuracy of the sensor must be taken into consideration.
- The self-diagnosis ability should also be considered.
- Information processing capability must also be considered.
- The area to be covered also impacts the selection.
- Fault tolerance should be considered.
- These sensors must be selected according to the ability to operate in harsh environment.
- Reliability in operation should be taken into consideration.
- They must have a good service life.
Basic components of a smart sensor
These sensors has five basic elements. They are:
Base Sensor
Base sensor is a conventional sensor that detects the physical quantity.
Power Supply
Power supply is used to feed power to the computing resource. Power supply may also supply power to the sensor base.
Microprocessor
Microprocessor is a computing element, that enables a sensor to make some data calculations which measure quantity. Microprocessor can also take actions based on these analyses.
Memory
The memory dedicated for storing measured values, and calculated data and storing the incorporated software logic which controls how the sensor will handle these data.
Communication Module
Communication module is used to transmit and receive data between the sensor and external devices over a similar network or the internet.
Working of Smart Sensors
A conventional sensor is used for providing the sensing capability. Conventional sensors are designed to measure the physical quantity and produce an analog signal. This signal must also be processed before it can be used.
Here, microprocessor plays a major role. This integrated microprocessor which is installed inside the sensor filters out the unwanted noise signal and convert the base signal into a usable form. The integrated microprocessor contains software functions that would make calculations which measure values and may act at specific values.
The memory card is also integrated within the sensor. It stores data which is measured and the operating parameters of the sensor. Also the communication module integrated within the sensor and will allow connecting to external devices by a private network or internet.
Use of Smart Sensor
These sensors are used for the same purpose as a normal sensor that measures a physical quantity. But it also has added data handling and communication capabilities which makes these sensors suitable for many industrial applications. These sensors are the most important elements in IoTs because of its communication abilities through the internet.
Types of Smart sensors
Smart sensors which are used in industries are mainly of five types. There are some special purpose sensor also available in market. The five types of smart sensors are:
- Level sensors
- Temperature sensors
- Pressure sensors
- Infrared sensors
- Proximity sensors
They are preferred over the conventional sensors because they have data handling capabilities. But there are still some applications where it is suitable to use a conventional sensor. If the application needs complete control over the sensor input, then it might be advisable to use a conventional sensor rather than the smart sensor.
Advantages of smart sensor
Smart sensors offer the following advantages:
- These sensors improve process’s performance
- These sensors generate data by connecting different devices and systems, hence enabling different machines that talk to one another. By this, it helps in:
- Monitoring equipment and system performance
- Comparing and analyzing data sets.
- These sensors generate data by connecting different devices and systems, hence enabling different machines that talk to one another. By this, it helps in:
- These sensors reduce maintenance by predicting failures of equipment
- They help in reducing unnecessary maintenance, cost of part replacements and potential for production downtime. Data collected by these sensors is used in detecting failure patterns, which eliminates the need for service equipment. These sensors can use the data for sending alerts to operators, notifying them for potential failure. Hence, they can take action before causing production downtime.
- These sensors can automatically log data for historical records and regulatory compliance
- In some processes and productions, manufacturers require to give some data records which prove their production parameters have set limits of their customers. When smart sensors are used, they can help automatically in this issue. The reason is that these sensors automatically log data like temperature, humidity, energy consumption, hours of operation, maintenance need and production line outputs.
- These sensors provide notification of problems which can process quality
- Smart sensors may identify system problems which could affect production output or the product quality and will provide real-time notification of them. This helps in avoiding production downtime.
- Smart sensors can self-test, self-calibration and self-diagnosis
- Theese sensors can do a self test during power-up so as to determine if a component has failed or not. Smart sensors also send a notification message to the process controller for taking proper actions. Smart sensors have the ability to self calibrate if needed.
- Smart sensors have the capacity to do multi-sensing
- A smart sensor is able to measure multiple physical quantities at the same time. Say for an example, a fusion liquid sensor is able to measure temperature, flow, pressure and density of a medium simultaneously.
- Smart sensors have high precision.
- The smart sensors can filter out signal noise and compensate for random errors. Hence, they increase the accuracy of the sensor.
Disadvantages of smart sensor
The smart sensors have the following disadvantages.
- Theese sensors have both actuators and sensors. Hence, they are more complex as compared to conventional sensors.
- Because the complexity is higher in wired smart sensors, so the cost are also higher.
- Sensor calibration must be managed by an external processor.
- There are pre-defined embedded functions that need to be given during the design of the smart sensors.