Data Loggers are an essential component of sensors and instruments. This electronic device records data according to a predefined need over time and in relation to a location.

Modern data loggers are based on a digital processor and integrated data loggers interface with computing systems and related software to analysis the collected information. The advantage of a central computer interface is immediately apparent to larger operations that may need to act quickly on information from a variety of data loggers at a variety of locations. Smaller logging units, typically stand-alone devices, may come with a small attached LCD screen and keypad for data that may not require immediate responses.

Data loggers can be set to start immediately, start on an event (either a trigger event or the exercising of an external digital input) or start with the application of an external magnet (which should be supplied with your unit).

Data Loggers and Data Acquisition:

From a terminology perspective, instrument manufacturers often make a distinction between a standalone data logger and those with direct contact with a computer-interface by referring to the first as a 'data logger' and the latter as a 'data acquisition system'. Typically using the word 'data logger' implies slower processing speeds and onboard storage even though both phrases can be used interchangeably. More sophisticated data loggers that can be integrated with industrial systems and alarms make continuous, remote monitoring a relatively easy task.

Temperature, relative humidity, air pressure and a variety of environmental conditions can now be logged from electrical signals and stored in an internal memory unit for later download to a computer. The fact that data loggers are deployed and often only checked sporadically elevates the need to install reliable and sturdy loggers from the onset. Onboard storage requires some form of date or time stamping to organise the data in a coherent manner. This memory may be battery-backed static random access memory, flash memory or EEPROM.

Logging units range from simple single channel input units to versatile multi-channel instruments. A rule of thumb would be that the simpler the device the less customisable its functions.

4 Main Types of Data Loggers

1. Low-cost Compact Single Input Data Loggers

Very specific non-customisable function. For example: a temperature data logging in a storage room.

2. Fixed Multi-Channel Data Loggers

Mounted units used to collect varied types of data in a single location. For example: RH, pressure readings and leak detection data in a manufacturing plant.

3. Handheld Multi-Channel Data Loggers

Portable units. For example: laboratory sampling worktops or field data acquisition such as weather conditions.

4. Modular Data Loggers

A configurable data logging component with can be plugged into an existing system for custom solutions. A modular logger is considered to flexible and is build with scalability and easy systems integration in mind. For example: a temperature data logger that can be built into a Programmable Logic Controller to ensure alarms are triggered on overheating.

Although manufacturers are using more and more standardising protocols it is a good idea to enquire about the compatibility of each of your process control components. Instrument protocols such as Smart Protocol, MODBUS standards and Canbus are the most common. Some data logging manufacturers make a point of utilising flexible scripting in order to allow a unit to interact with non-standard protocols.