In this lesson we will describe the difference between modifying addresses and forcing them. This lesson discusses what happens with either of these functions when the PLC power is turned off or when you are connected with your computer and you disconnect. The force function has an external indicator on the PLC which the modify does not. This is a quick indication when troubleshooting a program that something may be forced. The modify function has no indication when in use. Open up this lesson to give you a recap of the modify and force functions.