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How Do Temperature Data Acquisition Systems Work

temperature data acquistion

temperature data acquistion

Data acquisition systems are, at the most basic level, systems designed to collect data on a particular aspect of a physical process. Though long used in both industrial and scientific contexts, a growing number of hobbyists and semi-professional users are now recognizing the advantages of data acquisition.

Temperature data acquisition systems may be regarded as a sub set of generalized data acquisition systems. Temperature is often one of the most critical variables in any system, whether one used for industrial production or in specialized applications such as racing vehicles.

In addition, collecting data on the temperature of a system is often a critical safety requirement. If your equipment runs at its optimum only within a very narrow temperature range, or can be damaged by excessive heat or cold, you need to ensure that the data you are collecting on this variable is accurate and reliable.

There are several things to consider when setting up a data acquisition system for temperature, as there are with any kind of data acquisition system.

For more information on temperature data acquisition please take a look at our Nyquist and other DAQ Products.

Primarily, three factors need to be thought out:

 

Sensors

Perhaps the most critical part of your temperature data acquisition system are the sensors – the devices you will use to measure temperature. Unfortunately, it is very difficult to recommend sensors here, simply because the range of temperatures your equipment works within may be significantly different depending on the type of system you run.

To state the obvious, however, make sure that your sensors are able to deal with the expected (or even unexpected) temperatures produced by your system – a sensor freezing or overheating, and then giving inaccurate readings, is a sure way to damage your equipment.

Data Aggregators

The signal produced by your sensors must then be fed to a device that is able to aggregate and store the temperature data produced. In days past, the most common way in which this was done was by having dedicated Integrated Data Loggers in each piece of machinery. Then came DAQ cards, which represented an advance, but still required dedicated workstations to be set up for each part of the system being monitored.

Nowadays, a good approach is to go for a portable data acquisition system. These are normally stand-alone units, able to run under their own power and to upload data via a wireless network. This is especially useful when the system being studied is inherently mobile, or operates in a hazardous environment.

 

Data Analysis

Once temperature data has been collected, it must be fed to a central location and analysed. Whilst in the past this was typically done through bespoke software, which required technicians to know a number of programming languages, today there are better approaches.

Many of the portable data acquisition systems mentioned above come equipped with dedicated analysis software which requires no specialist knowledge to implement and use. This is especially useful for amateur or semi-professional users, giving them access to powerful temperature analysis tools that were previously the sole domain of highly trained engineers.

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How Field Data Acquisition Works and Where to Buy Them

image of daq basics background

image of daq basics

Field Data Acquisition presents significant challenges for engineers, but in recent years a new generation of DAQ devices have come onto the market that aim to take the hassle out of the process.

These devices are typically able to run under their own power for significant periods and in surprisingly difficult environments. They are lightweight and compact, meaning that they can be incorporated into many systems with little hassle. They are also able to upload data to a central repository via wireless networks, which makes the collection of previously inaccessible data possible.

Our products offer the latest in field data acquisition. To find out more refer to our product page.

 

The Challenges of Field Data Acquisition

There are several challenges to be overcome when trying to collect data in the field. First and foremost, one problem is that whilst the system under study might be a large, rugged, mechanical piece of machinery, data acquisition systems are notoriously fragile.

This can be a problem if the system you are collecting data on produces, or works within, a hazardous environment. In days past, it was often the case that every piece of machinery had its own dedicated data acquisition system, and was hard-wired to a dedicated computer terminal. At best, this meant the expense of running delicate cables far enough away from the machinery to keep the engineer safe. At worst, it meant that data acquisition was only performed during shut downs.

Another challenge of field data acquisition is that in many cases the system under study is inherently mobile, such as a vehicle. Since, as already pointed out, most legacy DAQ systems required hard links, these systems were essentially unable to access data from mobile machinery.

 

The Solutions

Much time and thought has been expended in trying to overcome these challenges, and the new DAQ systems coming onto the market go a long way to overcoming them. Modern DAQ systems are increasingly based on mobile DAQ devices, which are inherently portable in themselves.

Nyquist DAQ in action

These devices achieve this portability in several ways. Primarily, instead of requiring a hard link they are able to collect data from a variety of sensors, aggregate this, and then upload it to a central repository via commonly used wireless networks. Some of these devices even have the ability to produce their own Wi-Fi signal, making connecting to them in the field very straightforward.

They are also admirably light and compact. This means that even in machinery where internal space is at a premium, or in performance contexts where extra weight would be a hindrance, they can be incorporated into the system under study with a minimum of effort or performance loss.

Being able to incorporate a data logger into the design of machinery, and fetching data from it wirelessly, also means that time is saved that would be otherwise spent disassembling systems in order to download the data collected.

Lastly, these portable devices come equipped with an on-board suite of software that means they are able to do quite complex data manipulation by themselves, dispensing with the need for a dedicated workstation whilst in the field.

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How Multi Channel DAQ Works

image of daq basics in action

image of daq basics in action

At their most basic level, data acquisition systems are systems that collect and aggregate data on an external physical system. Whilst much thought is often put into the choice and design of sensors for DAQ systems, less goes into the choice of the data loggers these sensors are connected to.

One of the major advances of the past few decades has been the advent of multi-channel data acquisition systems. These systems are able to accept and aggregate a variety of incoming signals, whether analog or digital, and collect them in a format which is easily accessible for external data analysis software.

The History of Multi-channel Data Acquisition

In order to understand why multi-channel data acquisition was so revolutionary when first introduced, it is worth looking at the way that DAQ systems worked before the advent of multi-channel devices. Typically, a bespoke data acquisition system was required for each piece of machinery being monitored, often with obscure and mutually incompatible hardware for each.

As such, each DAQ, and in some cases each individual sensor, was hard linked to a dedicated PC workstation. This not only meant the extra expense of running delicate and unreliable cables to numerous discrete workstations, but also required arcane, custom software to be running on each terminal also.

types of DAQ systems

And of course, for systems that are inherently mobile, or operate within hazardous environments not conducive to PCs, data acquisition was almost impossible.

Multi-channel data acquisition changed this by allowing one device to collect data from a vast variety of sensors simultaneously. This had great advantages at all stages of the data acquisition system. By feeding the signals from a variety of sensors into one data collection device, DAQ systems were made significantly smaller, and could therefore be fitted to systems where space constraints previously limited this.

Multi-channel data acquisition devices also meant that one work station could easily aggregate all the data being logged from a particular system, greatly simplifying workloads and data analysis.

Choosing a Multi-channel Data Acquisition System

Today, almost all high-end DAQs for general use are multi-channel. Though each system offers its own advantages and disadvantages, one of the major distinguishing features of each is the number of channels available for data.

Some DAQ devices offer minimal channels, down to just two in some cases, and others offer huge number of inputs, with 256 channel systems becoming increasingly common.

When choosing a multi-channel DAQ, it is important to consider how many channels you are ever going to need on one device. Whilst it can be tempting to go for a large number of input channels, devices with large numbers of channels are generally expensive, and may offer far more than you will ever need.

A second factor to consider is the type of data you will be feeding to your DAQ device. Whilst most of these devices now offer both analog and digital inputs as standard, in some cases each channel is dedicated to a particular type of input, limiting your usage of each.

Only after considering these questions, and having decided the number of channels you require, should you give consideration to other features of DAQ devices, such as the ability to wirelessly upload data, or the software included with them.

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What is the Cheapest Data Acquisition Available?

image showing the cheapest DAQ options

image of daq basics background

Choosing a data acquisition system (DAQ) can be a real task. In recent years, the explosion of devices on the market, each with their own advantages and disadvantages, means that any DAQ you are considering probably comes with a bewildering array of extra features.

Getting a DAQ need not be expensive, however, if you carefully consider what you need your system to do.

I would never recommend going for the cheapest DAQ available, for a number of reasons. Firstly, if you are using a DAQ to monitor a piece of machinery that you’ve spent many hours working on, you need a DAQ that is reliable. Your system overheating because your sensors have failed is frustrating, to say the least. Secondly, many of the cheapest DAQ systems on the market today are designed as discrete, proprietary units, meaning that they will not mesh well with the rest of your equipment, and will be difficult and expensive to expand.

Luckily all of Daqifi’s products are both affordable and extremely reliable. To see more please refer to our product pages.

That said, it is possible to achieve good value when purchasing a DAQ system, if you keep a few points in mind:

How Many Channels Do You Actually Need?

Whilst it may be tempting to go for a monster, 256-channel DAQ system, for most people and organisations this is more capability than they will ever utilize. Think carefully about the how much data you need to collect, and in what format, and buy a DAQ system accordingly.

Of course, you can always start with a small DAQ system, and then expand. Which brings me to my second point:

Go For a Modular System

The best DAQ systems available today are modular. This means that if you buy a device today, and then in a few years decide to add a second, they will work well together. This is perfect if you are using DAQ as hobbyist or semi-professional user, because it means that your DAQ system can expand as your passion does.

It also means that these systems work well with most third-party components, such as sensors and software. This can be a real advantage if you don’t have the time to be debugging each of your sensors.

How Are You Going To Collect Data?

The absolute cheapest DAQ systems on the market today output data via hardlink. The price of these systems might be tempting, but to my mind it is worth going for a system that is capable of sending data via Wi-Fi. You likely already have a Wi-Fi network in your workshop or home, and it makes sense to use it rather than building a whole separate system to handle your DAQ.

Get A System With A User Interface

Again, the cheapest DAQ systems around output data as a raw string of numbers. This is great if you are a software engineer, but for the rest of us means we have to learn a complex programming language.

The better DAQ systems come with on-board interfaces that allow you to collect and display data in an intuitive manner, and to my mind systems like this are well worth the extra investment.

So, whilst it may be tempting to go for the absolute cheapest DAQ system available, in my humble opinion you should always invest a little more in a few key features that will ultimately save you time and money.