OPC Server: Start Stop Pause getData(again use) DYMOLA

I am using a Dymola OPC server

DYMOLA HAS these many tags which can be controlled using SimControl.Run, SimControl.Stop ,etc

here i wrote it in MATLAB

hostInfo = opcserverinfo('localhost');
da = opcda('localhost','Dymosim.OPCServer.1');
connect(da);
fprintf("CONNECTED\n");
grp=addgroup(da,'Demo');
itmIDs={'ModelVariables.Tco','ModelVariables.der(Tco)'};
itm=additem(grp,itmIDs);
area=additem(grp,{'ModelVariables.Area'});
set(grp,'UpdateRate',0.2,'RecordsToAcquire',50);
start(grp);
wait(grp);
[logIDs,Tco]=getdata(grp,'double'); // PREVIOUS ONE

Now I want to change/write value to area so what I did is this

write(area,23);

Now I want to Relog or getdata

NEWTco=read(itm,'device').Value; //using This I can read one instance
[NewlogIDs,NewTco]=getdata(grp,'double');// GIVES ERR