TelGas™ has the ability to record periodic data (data logging) in addition to event data. Data logging is used for analysing long term data (trends) at a low data rate. E.g. TelGas™ is often set up to save data at a rate of one data set every 5 minutes and the server will hold the data for a nominal 6 months. Logged data can be accessed from the standard TelGas™ control. The data can be either replayed as a mimic, exported or graphed (automatic Excel graphing). Post processing of logged data can be integrated with “event data” and the associated alarm messages.