Disconnect and delete all OPC Toolbox objects
You cannot reconnect a toolbox object to the server after you delete the object. Therefore, you should remove these objects from the workspace with the clear function.
Note that you cannot call opcreset if an OPC Data Access Explorer session is open, or if Simulink® models containing OPC Toolbox blocks are open. Before calling opcreset, close all OPC Data Access Explorer sessions and all open Simulink models containing OPC Toolbox blocks.
opcreset -force closes all OPC Data Access Explorer sessions and all Simulink models containing OPC Toolbox blocks, without prompting to save those sessions and models. If you use the -force option, you lose any unsaved changes to those sessions and models. Use the -force option only as a last resort.
Create an opcda object, and add a group to that object. Then delete the OPC Toolbox objects using opcreset, and clear all variables from the workspace.
da = opcda('localhost','Dummy.Server'); grp = addgroup(da); opcreset; % Deletes all objects % Clear the variables clear da grp opcfind