Page 50 - Occupational Health & Safety, November 2017

INSTRUMENTS
munication can wirelessly transfer data to a mobile device. Combined with a well- written application, Bluetooth loggers har- ness the power and connectivity offered by today’s smartphones, tablets, and other mobile devices.
Loggers using older Bluetooth versions require “pairing” with the mobile devices, which may not be practical for some lo- cations. Data loggers with newer Blue- tooth Low Energy (BLE) technology, also known as Bluetooth Smart or Bluetooth
4.0, can transfer data wirelessly without pairing. Instead, researchers simply use an app on their mobile devices to connect to any logger within range. BLE technol- ogy is well-suited to field data loggers, as it uses less battery power and can enable significant time savings when deploying loggers or retrieving data.
Important Features for any Temp/ RH Data Logger
Before comparing USB and BLE options,
it’s important to review the key features and capabilities of field temp/RH loggers in general.
Measurement Accuracy: Researchers need to ensure that loggers meet their ac- curacy requirements. Accuracy is typi- cally specified as +/-X, meaning that the recorded data is within that range of the true value.
Alarm notifications: An alarm is valu- able for alerting users when out-of-range conditions occur, based on temperature or humidity thresholds set by users when a logger is configured. Researchers who require immediate alerts will need loggers connected to the internet through cellular, Wi-Fi, or Ethernet technology. Alterna- tively, people working onsite may simply need a visual alarm on the logger or in the mobile app.
Processing data from multiple loggers:
Researchers using several loggers may want launch time-saving options for defining a deployment configuration once and using it to configure all the loggers. Also, a bulk- export or bulk-share option lets users ex- port or share multiple files at once. And an automatic upload option enables software to automatically merge data into a web da- tabase when the device or computer is con- nected to the internet.
Durability: BLE and USB temp/RH data loggers built to withstand harsh envi- ronmental conditions are available. When determining durability, it’s best to look for loggers rated International Protection (IP) 64 or higher, or National Electrical Manufacturers Association (NEMA) 4 or higher, and confirm that they are made from all ultra violet (UV) resistant materi- als. Moreover, outdoor loggers that can re- main sealed during deployments and data offload are more reliable.
Logging modes: Besides standard fixed- rate logging, researchers should determine whether they need any special logging modes, such as wrap-when-full, push-but- ton start or stop, time-date stop, event-trig- gered burst logging, or statistics logging.
User-replaceable battery: The ability to replace the battery in a field temp/RH data logger eliminates the need to purchase a new logger when the original battery dies.
Mounting mechanisms: Researchers should look for loggers that can be easily mounted in field sites using their preferred
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