Data Loggers

Data Loggers

A 'data logger' collects and stores time series of data from various types of instruments and sensors. The analysers included in the OPSIS DOAS system and laser diode system have powerful built-in data loggers that store data from both the analysers themselves and from the external sensors connected to them. OPSIS also offers stand-alone data loggers and Internet-connected devices for data transfer and remote control.


When monitoring emissions and processes, it is almost always also of interest to collect process parameters such as flue gas temperature, process pressure, and flue gas flow. Signals from such sensors are easily integrated into the OPSIS monitoring systems, both in analysers and stand-alone data loggers.

In simple cases, the sensors have analog outputs for measured value and perhaps a contact output to signal status. The signals are then connected to the monitoring system via the OPSIS module-based IOMan interface. IOMan can handle, among other things, voltage and current signals (active and passive), and closing and opening switches. More advanced sensors can have communication protocols to deliver information and OPSIS data loggers support about twenty different protocols.

OPSIS can supply several types of sensors, but it is also perfectly possible to connect sensors from other suppliers.


The 'web transfer' WT256 contains a data logger with the same capacity as those found in OPSIS gas analysers. Additionally, it also has an interface to the Internet, which makes it possible to forward data to external servers. It is therefore also used as a bridge between OPSIS gas analysers and the Internet. The WT256 is usually connected to the Internet using a wireless router.

The Internet connection also allows the functions of the WT256 to be monitored and controlled remotely, and connected gas analysers can also be remotely controlled through the WT256. It makes it possible to monitor the instruments and diagnose and to some extent remedy potential problems.

OPSIS cloud service OPSIS Data Services is based on data arriving from WT256. It is also a central tool in the OPSIS Monitoring Services. All communication with the Internet takes place via encrypted protocols. All services including the remote control option are password protected.


OPSIS DL256 is a stand-alone data logger with the same capacity and function as the data loggers included in OPSIS gas analysers. The DL256 can therefore be adapted to almost any data acquisition need. The DL256 collects data with one-minute time resolution and has memory capacity to operate for several years, even with many sensors connected. Communication software for remote control via serial connection is included in the data logger.

DL256 is an adequate alternative to WT256 and is mainly used in cases where it is not possible or not desirable to connect the equipment to the Internet.


On our blog you can read more about our products and what they are used for, for example:

Instrument Interfaces 

Planning for a Gas Monitoring System 


OPSIS Data Services

EN 15267-certified monitoring in waste-to-energy plants

Contact Carl K OPSIS 720X480pxl

Contact me if you want to know more about our data loggers!