//http://pengzhe1113.googlepages.com/
//Connct OPC Server opc_server_name
call('opc_connect',opc_server_name,1,'c','out')

//Add OPC Group opc_group_name
call('opc_add_group',opc_group_name,1,'c','out')

item_num=3
item_num_1=1
item_num_2=2
item_num_3=3

//Copy item name item_i (the index of the item_i is i)
call('copy_item',item_num_1,1,'i',item_1,2,'c','out')
call('copy_item',item_num_2,1,'i',item_2,2,'c','out')
call('copy_item',item_num_3,1,'i',item_3,2,'c','out')

//Add opc item's number  item_num
call('opc_add_item',item_num,1,'i','out')

//Read Item Value
item_read_result=call('opc_read',item_num,1,'i','out',[1,item_num],2,'i')

//Write Item Value
call('opc_write',item_write_i,1,'i',item_write_value,2,'r','out')

