Data recorders

Data loggers and data recorders are electronic devices that records data over time or in relation to location either with a built in sensor or via external instruments and sensors. Increasingly, but not entirely, they are based on a digital processor (or computer). Data loggers and data recorders are primarily used to store data for subsequent downloads to a host PC, but may also include real-time features such as monitors and alarms. Important specifications to consider when searching for data loggers and data recorders include differential analog input channels, digital I/O channels, sampling frequency, resolution, and accuracy. Data loggers and data recorders accuracy depends on the signal conditioning linearity, hysteresis, temperature considerations, etc. Common form factor for data loggers and data recorders include panel or wall mount, modular bay or slot system, rack mount, DIN rail and stand-alone. They generally are small, even portable, equipped with internal memory for data storage. Some data loggers interface with a personal computer and utilize software to activate the data logger and view or analyze the collected data, while others have a local interface device (keypad, LCD) and can be used as a stand-alone device. Data loggers vary between general purpose types for a range of measurement applications to very specific devices for measuring in one environment or application type only. It is common for general purpose types to be programmable; however, many remain as static machines with only a limited number or no changeable parameters. Common signal inputs available for data loggers and data recorders include DC voltage, DC current, AC voltage, AC current, frequency, and charge. Specialized inputs include encoder, counter or tachometer, timer or clock, and relay or switch. Common outputs for data loggers and data recorders include voltage output, current output, timer or counter output, relay output. Considering the user interfaces available is important when searching for data loggers and data recorders. User interfaces available include no display, front panel and display, touchscreens, hand-held or remote programmers, and computer programmable. Host connection choices include RS-232, RS-485, USB, Ethernet. One of the primary benefits of using data loggers is the ability to automatically collect data on a 24-hour basis. Upon activation, data loggers are typically deployed and left unattended to measure and record information for the duration of the monitoring period. This allows for a comprehensive, accurate picture of the environmental conditions being monitored, such as air temperature and relative humidity.