Online Monitoring of Functions and Function Blocks in Siemens Step 7

Step 1
In the FC that is calling FB or FC of that you want to monitor, select Debug>Operation

Step 2 
Select Test Operation and click OK​

Step 3
​Save the FC
​

Step 4 
And Download it

Step 5
When you right click on FB or FC, a new context menu line will be present - Monitor with Call-Up Paht.