This command was designed for exactly the situation you described:
Origin is being used as a DDE Server¹ with a worksheet and a graph displaying columns from that worksheet.
When data is appended to the worksheet using this command, the new data is drawn in the graph window without a redraw.

Here is an example anyone can try within Origin - you don't need Origin Professional for this. Open a New Project and run this script in the Script window:

%M=%H;
wo -a 1;
win -t plot;
y1=-1;y2=1;y3=.5;x1=0;x2=360;x3=30;
layer -i %M_B;
layer -i %M_C;
temp=SYSTEM.MATH.ANGULARUNITS;
system.math.angularunits=1;
for(angle=0;angle<=360;angle+=10) {
   v1=angle;
   v2=sin(angle);
   v3=cos(angle);
   plot -a %M 1 v1 v2 v3;
   sec -p .5;
}
label -a 120 0 Sine and Cosine functions;
SYSTEM.MATH.ANGULARUNITS=temp;