Data Acquisition (DAQ)
How to Choose the Best Data Acquisition System (DAQ)
Choosing the best data acquisition system, abbreviated as DAQ, for your applications can pose a challenge even to the most experienced test and measurement engineers and techs. The market is well-saturated with various options, and the technical specifications have become so broad that they require careful consideration during the DAQ selection process.
This guide aims to guide you through the process of choosing and acquiring the best data acquisition system for your particular application and list all the hardware and software considerations you need to take into account when selecting data acquisition hardware. Let’s start with data acquisition hardware considerations.
Data Acquisition Hardware Technical Considerations
There are a few considerations you need to take into account when selecting the hardware component for your data acquisition system, as they’re typically composed of dedicated hardware and software components designed to work together seamlessly.
In other words, even the best data acquisition systems on the current market aren’t designed as one-size-fits-all solutions. Instead, the design and configuration of a particular DAQ system significantly depends on the specific requirements of your application. As a result, you need to pay attention to the following factors:
Data Type and Sensor Compatibility
To understand data type and sensor compatibility, we have to briefly discuss the basic components of DAQ systems. These systems are made up of transducers (sensors), data acquisition hardware, and a computer. The latter can be a dedicated processing unit or a personal computer.
The first step in choosing the best data acquisition system for your application begins with determining the data type you’re collecting and processing. This subsequently determines the type of sensors and data acquisition hardware you’ll use for your application. Here’s an example:
Let’s assume your application requires monitoring temperature data in the 1000°C range. You’ll need an appropriate sensor, such as an infrared one from KEYENCE’s FT Series, to do the reading. The sensor will output an electrical signal, such as current, corresponding to the measured temperature value.
The signal is then sent to KEYENCE’s NR-HA08/08P or NR-TH08 measurement units, which condition the signal. These units then store the measurement data to KEYENCE’s NR-X100W, which is a multi-input data logger that stores the data for further analysis. This data logger can be connected to a PC for further data analysis and storage.
Of course, this is a broad oversimplification of the data acquisition process for illustrative purposes. Here’s a full list of common measurements that are monitored and recorded by the best data acquisition systems:
- Current
- Voltage measurement
- Temperature
- Pressure
- Strain and Force
- Displacement
Maximum Sampling Rate
Sensors typically measure analog properties, which usually requires converting an analog signal into digital. This introduces a sampling rate, or the number of times an analog signal is “sampled” in one second during its conversion into a digital signal. Naturally, the higher the sampling rate, the better, but the technical consideration also greatly depends on your application.
For example, some applications might require a sampling rate of 1Hz, which translates to one sample per second. On the other hand, vibration monitoring might need a sampling rate of 2,500 Hz or even higher.
Bit Rate
Bit rate, or measurement resolution, refers to the data acquisition system’s ability to detect small differences in signal. For example, an 8-bit ADC (analog-to-digital converter) divides the input into 256 different levels, while a 16-bit ADC divides the same input into 65,536 levels. Higher bitrates allow for more precise measurement.
It’s important to note that the best data acquisition systems allow you to customize the bit rate and the sample rate to match the exact demands of your application.
Filtering Capabilities
Filtering capabilities of your DAQ refers to the system’s ability to remove all unwanted signal content, such as interference or noise. This is an important part of any data acquisition hardware and an indispensable part of best data acquisition systems because it preserves the most crucial aspects of the signal relevant to the measurement while removing content that negatively affects the reading.
Data Acquisition Software Considerations
Best data acquisition systems come equipped with proprietary software, eliminating the hassle and cost of using home-grown data acquisition software solutions. Relying on proprietary solutions, even if they require paid maintenance or updates, is always advisable.
The system developers have designed the software to work seamlessly with their hardware by the time the DAQ was deployed to the market, which means that all the quirks and issues have been addressed.
What Digital and Bus Data Do I Need to Record?
A bus is usually a standard that allows microcontrollers and other devices to communicate amongst themselves without needing a host computer. You want to record this data, as it can help you with diagnostics and troubleshooting, performance monitoring, and data analysis and optimization of your automated systems.
This requires both software and hardware considerations, as the hardware has to be compatible with the bus protocol, and the software has to be able to interpret the data collected from the bus system and convert it into usable format.
Ease of Use, Features, and Functionality
When it comes to ease of use, features, and functionality, having user and operation manuals is a must, and those have to be written clearly and precisely—ideally in a searchable PDF file or an online resource. Whatever the case might be, make sure to familiarize yourself with the user and operation manual and, thus, the system’s features and functionalities.
The best data acquisition systems have an integrated context-sensitive HELP option that provides brief explanation/troubleshooting for each function, allowing easier operation. Additionally, when presented with the opportunity for online training courses and how to guide, consider enlisting yourself or your staff.
DAQ Customer and Technical Support
It’s always a good idea to ask what kind of technical support you can expect after selecting and purchasing the best data acquisition system for your application. It’s unreasonable to expect that the industrial application won’t have any “hick-ups” from time to time or perhaps a very specialized maintenance requirement.
These typically aren’t covered in user and operation manuals, so there has to be someone you can contact in case your data acquisition hardware or software requires a check-up.
Data Acquisition System Cost Considerations
Last but not least, cost considerations. It’s important to consider whether or not the data acquisition software is included with the hardware or is a separate purchase. Additionally, you should also inquire whether software updates are free or paid, what the hardware/software calibration cost is, and whether there is an annual maintenance fee associated with the best data acquisition system for your particular application. Have more questions about DAQ hardware? Contact us today.
