Datalogger

[beths]

What datalogger are folks using for validations? Why do you like or dislike it?

Thanks

[Deny Morlino]

What sort of validation? I have recently been looking at dataloggers for temperature and humidity monitoring. The brand I have narrowed things down to is T&D. Not sure if these meet your application needs. Expand on your requirements a little bit please.

[Mabel Adams]

There are many variables to consider. I assume you want NIST traceable. If you want to be able to change batteries and recalibrate you will pay more but the others are basically disposable. There are other issues like reading frequency, alarm displays etc. We use some by 3M that we ordered on line from the datalogger store--microdaq I think. They now have some that work at freezer temperatures as well as higher temps.

[webersl]

We use the Extech EA15 for annual cooler validations, new fridge validations, and even to prove to HVAC that lab's room temp is varying wildly and getting too cold at night and too hot in the day (even though that is, of course, impossible because of the expensive Johnson Controls computerized air handler they installed last year! ). I was so satisfied when I went to HVAC with a graph of the temps for the last 48 hours and they said, "Oooooo, do YOU have DATALOGGER??" - with envy and awe. I digress.

This datalogger (size of a walkie-talkie) has plug-ins for 2 probes, so you can do "upper" and "lower" in a cooler at once. You press the correct buttons and the logging begins - very simple. You choose how frequently the temp should be recorded (max interval = 255 seconds). It remembers 8800 data points. If I did my math right, that's almost a month of data on max interval. I've only used it up to a 3-day stretch before.

There is a software that you install on your PC (once). When you're done with the validation, you hook the handheld to your PC with the provided cord, and all the data downloads into the PC. The software is very basic and simple (temps with times and a graph), but the data can be saved and then imported into Excel for more fun with creating prettier graphs with titles and notes or whatever.

It comes cal'd to NIST, and our Biomed dept has a guy come to the hospital once a year to verify cal to NIST on all our handheld digital thermometers. Accuracy is good enough in typical blood bank ranges (down to -40C). We use the type "K" thermocouple probe for this application, but the EA15 takes other probe types too. Caution: the accuracy info that is advertised on all these dataloggers is for the reader - the handheld part. But the actual accuracy as used, is the accuracy described for the probe. [so readers will have this awesome accuracy listed, but the probes are the limiting factor on accuracy. So don't choose your datalogger based on advertised accuracy.] When you have someone check the cal to NIST on the datalogger (or any thermometer with plug-in probe), make sure they check the cal with the probe that you are using - not just the cal of the reader.

[beths]

Sorry I wasn't more specific-it would be for cooler validation purposes.

[Chris Leslie]

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Edited May 25, 2011 by Cliff
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[Miron]

I was also looking at data loggers lately. The most important criteria in our evaluation were the durability of the loggers, the size of the loggers (we want to place the logger directly in the product. The small volume of the logger is important to avoid its own mass to influence the measurement) and the possibility to exchange the battery by the user. NIST traceability is definitely a must for me and I require conformity to 21 CFR Part 11 since the data loggers are for use in the pharmaceutical industry. Finally the operating temperature must range from ca. -70°C (validation of refrigerators) to up to 140°C (validation of autoclaves).

I did my research and found there are a lot of brands out there but very little which fit all the above mentioned criteria. The Tracksense Pro Logger from Bakrona / Ellab (www.bakrona.ch/produkte/thermische-validierung/drahtlose-datenlogger/datenlogger.html) seem the best fit so far. From what I understand the software is validated and can be used to generate reports according to EN ISO 17665 / EN ISO 15883. I also know that nowadays most of the large pharmaceutical companies use these Loggers.

Hope this is helpful