Data Logging : Software

Most data logging software will perform two main functions :

• Recording data as it is collected.
• Displaying and analysing data as it is collected and after it has been collected.

Because the data logging system has a limited amount of RAM it can only store a limited number of readings from the sensors. When you design a system you will need to decide :

• Over how long the measurements will take place (the Period of Logging).
• The amount of time that should pass between each measurement (the Time Interval).

To decide these things you must use your common sense and think about what you are monitoring.

• If you are monitoring the pollution levels in a river you will probably want to take just a few readings every day over a long period such as a month.
• If you are monitoring the temperature of ice as it melts you will probably want to take readings every 30 seconds over 10 minutes.

The more frequently you take readings (or the more readings you take), the more computer RAM will be required to store them so it is important not to take readings too often.

• Graphs
• Tables

The graphs can be of different types. e.g.

• Line graph of a measurement such as temperature plotted against time.
• Scatter graph of two measurements (such as light and temperature) plotted against each other to see if there is a relationship between them.

Some organisations will perform much more sophisticated analysis of data collected by data logging than the software that will run on a home PC can. For example the Met. Office uses a very sophisticated computer model to analyse data collected using data logging equipment to produce a weather forecast.

GCSE ICT Companion 04 - (C) P Meakin 2004