Download Data Logging - ITGSconti-2009-2011

Mehnaaz Asad
IB2-3
What is
data
logging?
Data logging is the collection of data over a period of
time, and is something often used in scientific
experiments. Data logging systems typically monitor a
process using sensors linked to a computer. Most data
logging can be done automatically under computer
control.
IT System:
Hardware
•Sensors
•Data-logger is a
basic box capable of
picking up and
storing signals from
sensors.
•Computer
Normally, the
sensors are plugged
into the data-logger
circuit box which in
turn is connected to
the computer.
Optionally, a
printer is also useful
for printing out
graphs on paper.
IT System: Software
The common functions of a data-logging program are as
follows:
 Take readings from the sensors at regular intervals. It is
possible to take many readings at time intervals ranging
from a few microseconds to hours or even days.
 Present the data in a suitable form of display on the
screen.The graph plotting facility is particularly useful since
the computer can generate them very quickly allowing the
software to compare several sets of results.Also, the
program provides aids for accurately analysing the results
and performing calculations on the data.
 Print the data table or graph on paper using a printer
connected to the computer.
 Store the data on a computer disc for future use.
Continuous recording
independently from the
computer using a dataThe rapid repetition of
measurements (hundreds of logger. Data logger may be
sited in locations which are
values per second)
not convenient for
computers.This is well-suited
Simultaneous recording
to longer term experiments.
Measurements from several
sensors may be collected
Delay
simultaneously.
A data logger may be set up
so that it waits for a
Period logging
specified time before
Data may be collected over beginning to log data.
a period of hours or days.
Remote Logging
Data may be collected
Process
 The sensors send signals to an interface box,
which is linked to a computer. The interface
box converts analogue signals to digital signals
that the computer can understand.
 The computer controlling the process will take
readings at regular intervals. The time
interval for data logging is the time between
readings. The logging period is the total length
of time over which readings are taken.
 The readings are stored in tables and can be
displayed in graphs or passed to an
application, such as a spreadsheet, for later
analysis.
Example
1
The following describes an
experiment to determine
the rate at which water
cools down from boiling
point:
A temperature sensor is
placed in the liquid.
The sensor is connected to
an interface box linked to
the computer.
The data
logging software is set to
take readings every 30
seconds (time interval) for
25 minutes (logging
period).
Interpretation
The data logging
software will
typically store the
readings in a table.
The data can later
be analysed using
graph tools.
A graph which could
be used in this
experiment is
a cooling curve
graph.
•How much light would a leaf get? (light sensors)
•Best thermal insulators? (temperature sensors)
•What material is most sound proof? (sound sensors)
•What are the best atmospheric conditions for a
greenhouse? (combination of sensors)
PROS
 Improves the accuracy
 Collects information from scientific experiments




and monitoring systems faster than humans
Displays the results in a graphical form
Prints out and analyses the results
Ease of use / display on a screen / drafts and
analysis of the results.
Remote logging enables to calculate the
experiments from remote locations that are
inaccessible by humans and many computers.
CONS
 Storing data logging systems in the databases
is very complex and hard to manage
 It is hard to implement the data logging
system.
 Software has to be designed properly, in
order to work with the hardware.
 High performance computers are needed in
order to analyse the data.
People and Machines: We are becoming too dependent on
the technology and, if necessary, might not be able to
perform the actual experiment that confidently.
Equality of Access: Those who don’t have access to this
technology lose out and have to record data manually.
Integrity: The data entered has to be correct and accurate,
or else it raises the issue of reliability as well.
Health: You don’t have to come in direct contact with any
harmful chemicals while recording the data.You can
monitor from a safe distance.
http://www.ruthtrumpold.id.au/itgswiki/pmwiki.p
hp?n=DataLogging.DataLogging
http://www.ncte.ie/documents/advicesheets/32Da
taloggingNov08.pdf
http://www.bbc.co.uk/schools/gcsebitesize/ict/meas
urecontrol/3dataloggingrev1.shtml
http://www.hitchams.suffolk.sch.uk/datalogging/ex
amples.htm
THE END