Automated Test and Measurement Applications
Manufacturing Automation Services provides the highest quality Test and Measurement solutions for your automated manufacturing system.
Data acquisition is the process of using sensors to measure physical phenomenon such as voltage, current, temperature, pressure, vibration, sound, etc. Any sensor that can convert these physical properties to voltage or current signals can be used in a data acquisition system. Selecting the appropriate data acquisition hardware is important so that you can accurately collect and measure data. Signals are typically classified as analog (continuously varying in time) or digital (discrete values in time). Additionally these signals can be further classified as low or high speed. In some applications, it’s important to be able to acquire signals simultaneously and synchronized to a common clock or time base. [Leo – thinking about this…] How about a topic called “Image Acquisition” right after data acq? Does it fit in here?
Once the data has been acquired, some processing is typically required before being logged and / or presented to the user. Many different commercially available off-the-shelf tools exist to analyze data, in addition to creating custom algorithms. Data analysis and allowing the software to act on the processed data is the heart of an automated test system. For example, acquiring vibration data on a factory-floor machine and analyzing the data can help determine whether maintenance is required. On the other hand, processing images captured by high speed cameras can quickly help the user determine any product defects. Processing power is limited only by the latest PC technology.
Typically applications will require some form of data storage, this can be in the form of simple text files, or more sophisticated means, like a database management system. Relational databases can hold large amounts of data, and can be easily queried. Also, databases are generally centralized and therefore many different clients can connect allowing for a centralized data repository.
Using standard off-the-shelf instruments are common in test systems. Acquiring data can be accomplished using a variety of different hardware. For example, to acquire temperature data one can use a stand-alone temperature logger, where its sole purpose and functionality is to acquire and log temperature. The advantages are that it’s portable and can be setup quickly with minimum user interaction. On the other hand, some disadvantages are that acquiring mixed signals (like temperature and pressure) at the same time can be difficult. Stand-alone instruments have a specific function and they only perform that function. Most instruments have the ability to be controlled via the PC using a GPIB, Serial, USB or Ethernet connection, enabling them to be integrated into an automated test and measurement system.
Measurement devices are required for any data acquisition systems. It is important to select the appropriate device when acquiring signals to avoid unwanted, or artificial, data. For example, some sensors have an anti-aliasing filter that filter out high frequency signals that are associated with electrical noise. Other times, sensor will condition the electrical signals to the appropriate voltage level.
When designing an automated test system and developing a test system architecture, there are several system design considerations and challenges that need to be addressed. Using a test executive helps to standardize on a modular system architecture. Using adopted industry standards, the modularity that test executives provide help to: