I am about ready to do a project with many PID loops therefore I am doing a little research on the strengths of Siemens Step7 software. I have found that Step7 already has some predefined function blocks for PID control. these blocks are SFB41 for continuous control and SFB42 for step control. I've managed to find these blocks in the Step7 Standard Libraries but don't know how to go about making a call to them so that I can use them in my application. Does anyone out there have any idea as to how to go about doing this?. your help will be appreciated, Thank you!