S7-300 PID Control

Hello, I need help with Step7 PID control. I have never programmed a PID in Step7 and have no examples to work from. I am using FB41 (CONT_C). I am using the help file but I am not clear on some stuff:

It says that MAN_ON default setting is TRUE.
So, I must use a false bool to enable the PID action, otherwise LMN = MAN?

For SP_INT & PV_IN are REAL data type in the specified Range = -100.0 to +100.0 (%) or phys. Value 1.
Does this mean that my SP and PV must be scaled to real data -100 to 100? So if I'm controlling ppm 0-1000, then 0 needs to be scaled to -100 and 1000 needs to be scaled to 100? Also, what does "Value 1" refer to?

I am using REAL data for the PV input.
Should I leave the PV_PER input blank and the PVPER_ON equal to a false bool value?


Thanks for your help. If anyone is looking for bonus points, I would love and greatly appreciate to see an example of the FB41 setup for my application.

Control Value is an output that is a REAL datatype with a range of 0-0.5.
Process Variable is a real REAL datatype input of 0-1000.
Setpoint is a REAL datatype input of 0-1000.
(I have already converted all of my peripheral values to real data)

I will have real inputs for P,I,D values, as well as a bool to toggle manual/pid output (manual/auto) setting.

Thanks!

Search this site. There's several samples

Thanks. I see the examples but I have not been able to find the answers to some of my specific questions. My main question is about the scaling of the SP/PV data. Is that how this is done?

Also, is it really necessary to put the block in OB35? What is the point of the cycle time if you must put it in a cyclic block? I like to keep all my code organized within blocks that I define, based on the purpose of the blocks. If its absolutely necessary, would using a bit that toggles on/off in OB35 suffice?

Thanks