Buying a data logger? - Things to consider first!

Lontek's quick data logger questionnaire & summary.

1. How many and what type of sensors do you need to record?
2. What recording interval or sampling rate is required? e.g. every 10 seconds
3. How long between manual or automatic data downloads?
4. Will the site location have mains, battery or solar power?

Now, look for someone who has good product and industry knowledge to supply a data logger fit for purpose. They should offer free or paid after sales support. E.g. Here at Lontek, we live and breathe data loggers and feel you need to offer more than just an "online shop" when selling data loggers in Australia!
So feel free to keep reading if you like us enjoy the technical stuff, or call us now and we can guide you with your purchase.

Know what you want to record!

There are hundreds, if not thousands of data logging applications. No two projects are the same, although many will use the same type of data logger or data logging software. So that leads to the following questions.

What parameters need to be measured?

A data loggers can record electrical signals from dozens of different sensor types. Typically used sensors are Temperature, Humidity, Voltage, Current, Electrical energy, Water pressure, Hydraulic pressure, Flow rate, Speed, Acceleration, Strain, VWSG, Charge, TEDS Sensors, IEPE, Wind speed, Wind direction, Rainfall, Solar radiation, Logic, GPS data and the list goes on.

What Accuracy is required?

This is one question that only the user can answer. Firstly, there might be Quality Assurance or a Regulatory standard that needs to be considered. In many cases, the best practical accuracy possible is what should be aimed for. This means you should look for good accuracy from your data logger and sensors, although try not to go overboard.

Here is an example. Is better than ±1°C when measuring ambient air temperature in a commercial office required?

A Building Manager might be happy with an accuracy of ±1°C and a resolution of 0.5°C, while a Scientist researching indoor air quality in the same office might want an accuracy of ±0.3°C and a resolution of 0.1°C. So potentially yes, some applications will warrant better than good accuracy.

Total System Accuracy and Resolution?

When considering the accuracy, you need to know the Total System Accuracy . This will include the data logger, any wiring, plus the sensor and the software. Some manufacturers will only quote the accuracy of their data logger or sensor, so double check the total system accuracy to ensure it is within your required limits.

Resolution is also balanced around accuracy. Just because a temperature data logger can display down to one decimal place (Resolution), that does NOT mean the Accuracy is as good. You can have good Resolution without the Accuracy!

More about Accuracy, Resolution and Precision here.

Sampling and Recording?
Most smaller data loggers will only record a single spot reading at a set time interval. This is typically seconds to minutes and sometimes even hours for most data logging applications. You should always try to over sample by fifteen times the rate of change as this will give you good resolution in your data.

The more featured data loggers have the capabilities to apply statistical data analysis on the fly. Averaging is the most common. E.g. The data logger might have a sampling rate of once every second, with a recording rate of once every minute. In this case, the data logger will temporarily store up to 60 readings, then record the average of those 60 readings every minute.

How will you manage the data?
This can be critical. You need to plan how the data will be retrieved and then ensure that the data is retrieved before the internal memory of the data logger is full.

Data retrieval options range from manual collection via a computer, USB memory device or SD card transfer, to automatic scheduled transfers via FTP or e-mail. Swapping out the entire data logger with a spare unit is also and option, data is then generally retrieved back at the office.

Another factor with data retrieval timing is when recording a large number of sensors, or at a fairly fast sampling rate. The ability to then post process the data file can be problematic. Some software applications or even the computer can struggle to handle large data files and a large number of data points in the data file.

So as a good rule of thumb, record the data you need, and can then process.

Mains or Battery Powered?
This is generally dominated by the application and the location where the data logger will be used.

Small data loggers will often run from an internal battery for a few weeks to many years. So they will be convenient in any situation. The more featured data loggers often use more external sensors, and they will require more power than a small internal battery can deliver. Mains or battery power are the two main options.

If mains power is available, then great. If not, a balance between the data logger's performance, any connected sensors and power consumption will need to be found if the project is a permanent or semi-permanent installation.

Running the data logger and sensors from battery power can work well. Often Solar Panels are used to charge the battery. Other times the battery is simply swapped out with a freshly charged battery when the data is collected from the site.

Communicating with the Data Logger!

  • Direct to a Computer via USB or RS232 cable.
  • Local Area Network (LAN) or Ethernet Network, or Wi-Fi.
  • Via the 3G or 4G Cellular or Data Networks.
  • Satellite communications.

In many applications, communicating with the data logger is done via a USB cable connected directly to a computer. This computer will have the manufacturer’s data logging software installed for setting up the data logger, retrieving and displaying data, etc.

Taking the time to set up the data logger to work on your LAN or Wi-Fi can be a little tricky, although this will greatly depend on your IT Administrator and any Company policies.

Communicating via 3G and 4G can be a lot trickier depending on what you exactly require. There are various issues from Firewalls, Dynamic and Public IP addresses and Dynamic DNS registration services. Plus setting up a VPN to ensure your data is secure, will just add another layer to the complexity.

Tip! Sending or Pushing data back to a server or your e-mail address over 3G or 4G is fairly easy, a standard data SIM card can usually handle this with ease.

It becomes more complicated when you want to "Remotely" access the data logger at any time. So consider if you really need this access and what you need this access for. It might be possible that the data logger could be configured to send alerts or alarm messages to same the manual remote monitoring.

Satellite communications are available, although they only seemed to be used when absolutely necessary. It would best to contact us to discuss this one.

Software to compliment the Hardware
Different brands of data loggers have their little subtleties. They all have different software, some shine in one way or another. In general, the software that comes with a unit will perform the basics of setting up the data logger, retrieving data, then displaying the data in a chart or table format. Most of the software applications will export the data in CSV format which can then be opened in MS Excel or LibreOffice for further data analysis.

Data Logger Calibration
Once you have your data logger and sensors installed, you should calibrate the total system to ensure that the data logger, any wiring, the software and any sensors are working correctly. At minimum, validating the total system is working correctly with a few simple checks is a must. e.g. When measuring ambient temperature, a small thermometer placed near the temperature sensor for a few minutes should give a comparable reading to the data logger.

See more about calibration here.

Time to find someone that Knows!
Maintaining a good product knowledge is hard work when you just specialise in data loggers, and that's only if you are selling a handful data logging brands. Plus you then need to understand how the data logger will be used in conjunction with the many types on sensors available on the market. Yet without this product and industry knowledge, recommending a data logger that will perform the required task may not always be possible.

So ensure you purchase a data logger from someone that has good product and industry knowledge and doesn't need to refer back the often overseas manufacturer for the simplest of questions.

Support Support Support
This is one thing that can not be overstated. The local after sales technical support is worth more than the few dollars saved buying a data logger on-line in a foreign currency or from a supplier that sells so many different products they just don't know which item you are talking about.

While some small low cost data loggers are simple to use, others can be a little tricky at first. So being able to pick up the phone or send off a quick email to ask a question from someone with industry experience and good product knowledge will ultimately save you time and money.

Other issues like firmware and software updates, Windows updates or even "I haven't used the data logger for a while" will also benefit from good quality local support to keep your data logger running nicely.

Lontek, we sell data loggers

Lontek sells a range of data loggers that can accommodate hundreds of data logging applications. We represent both local and overseas manufacturers directly, plus we custom build dedicated data logging systems. You could say that data loggers are what we specialise in. Plus we carry a fair range of local Australian stock for a quick delivery.

Lontek has been selling and specialising in data loggers for over 15 years. We have an extensive Electrical and Electronics background. This technical experience allows our sales & technical staff to assist customers with confidence. We stand by the products we sell and we do our very best to recommend a suitable product from our range.

If we are not 100% sure a product can perform the required task, we will set up a data logger to prove it first. Purchase a unit you know will be fit for purpose!

Rental energy data loggers

Need to rent a power data logger for an energy recording job? Then talk to Lontek as we specialise in renting three phase power data loggers. When you hire a power logger from Lontek, you can be confident that someone at the end of the phone can actually assist you. More...

Get your data logger calibrated

Calibration is a must for many customers. While others just like to know that their data loggers are accurately recording data. Here is a good example of how a calibration can improve your data. More...

Looking for a Data Logging System instead?

Lontek offers a complete range of data loggers in Australia. Single channel low cost units through to multiple channel units supporting up to 800 channels. In addition we also offer wireless data logging systems for portable or fixed applications.

In conjunction with our partner company LabCraft, Lontek can supply, install and commission your next project or simply just supply all of your data logging equipment.

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