The data measured by sensors needs proper signal conditioning before it can be measured accurately by a data acquisition system.
The accuracy and the quality of the data are enhanced by signal conditioning, which cannot be accomplished by using a data acquisition system alone. There are plug-in DAQ devices available, which are exclusively made for measuring voltage, which is one of the Input/Output parameters needed to run modern applications.
Majority of the data acquisition systems need to measure the signals got from sensors that sense physical, mechanical and chemical processes. The data from sensors such as Strain Gauges and RTD’s must go through signal conditioning in order to produce accurate results. The process of signal conditioning is simple, users just need connect to the sensor signal, subject it to appropriate signal conditioning, convert it to digital form and display it on the screen. In order that the data acquisition system reads the signal accurately, it is vital to have the signal conditioning hardware integrated into the system.
Data acquisition systems are used in numerous applications such as laboratories, on manufacturing plants and in field services. The process of signal conditioning is illustrated below using a thermocouple. Consider a thermocouple and to measure the thermocouple signal it needs amplification, filtering and cold-junction compensation. The amplification of the signal is required because of its small magnitude and should be near the thermocouple to increase the signal to noise ratio. Filtering of the amplified signal is necessary to eliminate unwanted noises from the power lines in the environment and other electric devices. Finally, cold junction compensation is required to nullify any difference in temperature that is present between the measurement junction and the junction connected to the data acquisition device.