Data acquisition (DAQ) is used for analyzing and monitoring different types of industrial processes and systems. It involves taking and processing electrical and electronic signals from various devices such as: analyzers, timers, relays, processors, sensors and solid state networks, etc. An assortment of devices such as: data loggers, input and output modules, chart recorders, and computer boards are used for data acquisition purposes. Data acquisition is essential to many types of businesses as it allows them to get the data that is needed from testing, recording and analyzing devices. This process is commonly used in weather forecasting offices, aircraft traffic control, mechanical testing, and most types of monitoring and maintenance processes.
There are three mains steps to data acquisition, which are recording, processing and visualization. You need to record all of the data that you gather so that you can use it, refer to it and compare it to other data at a later date. These measurements can be gathered as wave forms and as graphs.
Once you have collected the data it then needs to be processed so it can be transferred to a computer database. You can do this by using DAQ software to transfer the raw data into a readable type of electrical signal. DAQ hardware is then used to gather the recorded data and to transfer it to the computer system.
When you have the data transferred and stored in the computer, other types of software programs will be able to show you the recorded information on the screen. This visualization will let you see, understand, and manipulate the data in the way you need to perform your tasks.
Factors for selecting data acquisition equipment include: analog input channels of differential type, digital output and input channels, frequency of sampling, accuracy and resolution. Signal inputs that are used are: DC/AC, voltage and current, charge and frequency. Sensors that are used to give inputs are: strain gages, thermocouples, LVDT's, thermistors, accelerometers, RVDT's, tachometers, relay switches, timers, encoders, and counters, etc. Some connections to the host equipment are: RS232 cables, radio, direct backplane interface, GPIB, TTL, Ethernet, modem, telemetry, parallel and SCSI.
The rate of data transmission and web enabling should be taken into consideration while selecting the data acquisition equipment.