9-1.Function Summary 
 
For  general  PLC,  when  the  internal  optical  couples,  relays  or  transistors  are  damaged,  the 
corresponding input/output terminals will be faulty. The only solution is to revise the program. 
This is troublesome for the user and affects the production greatly;   
XC series PLC  breaks the one-to-one correspondence. The users only need to change the soft 
component’s value by HMI, then the corresponding terminal will activate. Take advantage of this 
improvement, the user need not replace the PLC or modify the original program in the condition 
of PLC terminals damaged.