Short Answer:

A Data Acquisition System (DAS) is used to collect, process, and store data from sensors or instruments for monitoring or analysis. Based on how data is collected and processed, DAS is mainly classified into analog, digital, and hybrid types.

Each type has its own application depending on the nature of the signal and system requirements. Analog DAS handles continuous signals, digital DAS works with digitized data, and hybrid DAS combines both, allowing greater flexibility and accuracy in modern systems.

Detailed Explanation:

Types of data acquisition systems (DAS)

A data acquisition system is an essential part of any measurement or control process where data needs to be collected from various sources like temperature sensors, pressure sensors, strain gauges, and more. DAS is responsible for measuring physical parameters, converting them into electrical signals, and then processing, displaying, or storing that data for further use.

Depending on the method of signal handling and system design, data acquisition systems are categorized into the following main types:

1. Analog Data Acquisition System (Analog DAS):

• This type of system deals with continuous signals, meaning the data changes smoothly over time.
• It consists of sensors, signal conditioners, and analog recording or display devices like analog meters or chart recorders.
• No conversion to digital form takes place in analog DAS.

Key Features:

• Works with continuous voltage or current signals.
• Simple and cost-effective.
• Used in basic or older systems where digital processing is not needed.

Applications:

• Direct analog temperature or pressure monitoring.
• Real-time visualization in analog meters.

2. Digital Data Acquisition System (Digital DAS):

• This system converts analog signals into digital signals using an Analog-to-Digital Converter (ADC).
• Once the data is in digital form, it can be stored, processed, and transmitted using microcontrollers, computers, or digital memory.

Key Features:

• Offers high accuracy, easy data storage, and better processing.
• Can interface with software systems for automation and analysis.
• Requires components like ADC, processor, and digital display units.

Applications:

• Industrial automation and control systems.
• Weather monitoring stations.
• Biomedical equipment like ECG machines.

3. Hybrid Data Acquisition System (Hybrid DAS):

• This system combines both analog and digital features, offering the benefits of both types.
• It can process some data in analog form while converting other signals to digital for further processing.
• Common in systems that require high-speed analog response and accurate digital output.

Key Features:

• Flexibility to handle various signal types.
• Can be customized for complex systems.
• Provides both real-time analog output and stored digital data.

Applications:

• Aerospace systems.
• Scientific research instruments.
• Large industrial monitoring systems.

Other Classifications (Based on Operation):

• Real-Time DAS – Provides immediate processing and display of data.
• Remote DAS – Used for collecting data from locations far from the central processing unit.
• PC-Based DAS – Utilizes computers and data acquisition cards to collect and process data using software.

Conclusion:

Data acquisition systems are classified into analog, digital, and hybrid types, depending on how they collect and process signals. Analog DAS is used for simple, continuous signal monitoring, digital DAS for modern digital processing and storage, and hybrid DAS for flexible applications that require both analog and digital handling. Understanding these types helps in selecting the right DAS for any measurement, control, or analysis task in electrical and electronic systems.