 Hello. So in this session, we will discuss the data acquisition system. So learning outcome of this session, the student will be able to apply the fundamentals of data acquisition system to develop the electronic product. So in this session, we will discuss the concept of the data acquisition system. Then what are the components of data acquisition system and the general microcontroller based data acquisition system. So the data acquisition system, it is the process of sampling the signals and measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Now see, as far as the electronic products are concerned, most of the electronic products nowadays are based on or consists of the one of the processor or controller. In most of the product, what they do, they are requiring to send some parameters from the real world. So for example, you can take the product like the temperature controller. So for temperature controller, very first step is to sense the temperature. So for that, we are using the different available sensor. So the sensor is used to sense the temperature. So the output of the temperature sensor, it is in the form of change in resistance or something else. Then that change in resistance is need to convert into the voltage, mainly in the analog voltage. Then the analog voltage is need to convert into the equivalent digital value so that we can feed that value to the controller for the processing purpose. So most of the times in the real world, the different parameters is need to sense like the temperature, pressure, humidity, displacement, movement of the object like that. And this is need to convert into the suitable form, mostly in the digital numeric values so that the controller or the computer can be used to process this. So the main components of this data acquisition system are sensors, then the signal conditioning circuit and analog to digital converter. So sensors are used to convert the physical parameters like the temperature, pressure to electrical signals. Then the signal conditioning circuits are convert the sensor output into a form that can be converted to digital values. And analog to digital converter, it is used to convert the condition sensor signal to a digital value. And now this digital value can be transferred to the controller for further processing. So the general look of the controller based data acquisition system will be like this. The first part is the physical system, then the sensor slash transducer, then the signal conditioning circuit, then ADC to convert into the digital form and for processing the controller or the computer and then some output devices may be there to form the entire system. So physical system means actually it is the input to the data acquisition system which can be converted into the digital form. So from physical system it may be a temperature, it may be a pressure or humidity or the displacement like that. Then the next block is the sensor slash transducer. Broadly speaking we are saying that the sensor and the transducers are one and the same but actually the sensor is the device which sense the physical quantity like temperature, pressure and converts this into the analog quantity. It may be a change in resistance, it may be a change in voltage like that which can be measured electrically that is such as voltage, capacitance, inductance, resistance. While transducer is also device but it converts the one form of energy into the another form. Example for the transducer is a microphone. One is converting your sound signal loudspeaker is used to convert into the sound. So the sensor may be a part of the transducer. So there is the difference between sensor and transducer. Now the signal conditioning circuit. This particular circuit it is actually used to increase the strength of the quality of the output signals of the sensor and transducer. Now output of some sensor is suppose in some milliholt. So it is required to amplify for further processing. So for that this signal conditioning circuit is used or the output of the sensor may be in change in resistance. That change in resistance is need to convert into the voltage which can be converted into the digital value. So signal conditioning circuit it is actually functioning as an amplification, linearization, filtering, attenuation, excitation and so on. The analog signal is converted into the digital signal by using A to D converter. So the ADC can be selected based on the accuracy, resolution, number of bits required. And then this digital data is given to the processor for further processing. Now this is the general data equation system with the controller is shown. The three sensors are shown. Sensor 1, sensor 2, sensor 3 they may be a same type of sensor or they may be a different type of sensor. Then the corresponding signal conditioning circuit may be there. Signal conditioning circuit 1 which will convert the sensor 1 output into the suitable form which we can apply to the ADC. Similarly the signal conditioning circuit for sensor 2 for sensor 3 like that. Then now the analog multiplexer or digital multiplexer as per the requirement may come into the picture to select one of the output from the signal conditioning circuit because the ADC can convert only one voltage into the digital at the same time. So it is required to select the proper input to the ADC. Then the ADC will convert this into the digital form and then it is processed by the controller and as per requirement further it is communicated with the PC or directly we can display the information on any display device that depends upon the particular application. But this is the general look of the data acquisition system. Sensor signal conditioning circuit multiplexer may be there if you are going for number of sensors then ADC to convert into the digital and then PC or the controller for the processing purpose. Now you just pause the video and think how to build the data acquisition system for say the temperature controller using the sensor RTD. Now see this is the general steps to build the data acquisition system for temperature controller using RTD. So the RTD's output is in the form of change in resistance. So to detect this change in resistance we can put this RTD in a bridge circuit. So for that it is required to design this bridge circuit. So this bridge circuit is a part of our signal conditioning circuit. Then this change in resistance in the RTD is need to convert to voltage by exciting the bridge circuit. Then if required it is need to amplify at particular level so that we can convert this to digital value. So this is the sensor whose output is change in resistance. Then design of the bridge circuit then conversion of change in resistance into voltage amplification of this voltage is a part of signal conditioning circuit. Then convert this to digital value by using ADC and then provide this ADC output to controller for further processing. So these are the general steps to be followed while designing the data acquisition system for temperature controller. References used, Electronic Product Design Book by R. G. Kaduskar and Handbook of Modern Sensors by Jakob Pradhan. Thank you.