Start a logging task
start(GObj) starts a data logging task for
GObj can be a scalar
dagroup object, or a vector of
dagroup object must be
contain at least one item for
start to succeed.
When logging is started,
GObj performs the following
Start event, and executes
'on' and issues a warning.
Removes all records associated with the object from the OPC Toolbox™ software engine.
Logging property to
Start event is logged to the
GObj will stop logging when a
stop command is issued, or when
Configure and start a logging task for 30 seconds of data:
da = opcda('localhost','Matrikon.OPC.Simulation'); connect(da); grp = addgroup(da,'StartEx'); itm1 = additem(grp,'Triangle Waves.Real8'); itm2 = additem(grp,'Saw-toothed Waves.UInt16'); grp.LoggingMode = 'memory'; grp.UpdateRate = 0.5; grp.RecordsToAcquire = 60; start(grp);
Wait for the logging task to finish, then retrieve the records into a
double array and plot the data with a legend:
wait(grp); [itmID, val, qual, tStamp] = getdata(grp, 'double'); plot(tStamp(:,1), val(:,1), tStamp(:,2), val(:,2)); legend(itmID); datetick x keeplimits