I wanted to know about 2 values in PID block,

1.TM_LAG (TIME LAG OF THE DERIVATIVE ACTION)

2.LMN_PER (MANIPULATED VALUE PERIPHERAL)

What are their fuctions? I understood the Data type but i cannot be able to understand the usage.

Please see attachment for more detailed info, but in general:

TM_LAG: Let say if the TD (derivative) action is needed it wont repsond right away it will wait x seconds what ever you set TM_LAG to be and then starts acting on the controller. if you dont input any value for TM_LAG default is 2 seconds.

LMN_PER: means you dont have to unscale your manipulated value. the controller will unscale it for you and you just attach your out put to it.

rememebr you have to scale your PIW samething when sending outputs you have to unscale PQW.

LMN_PER in siemens FB41 uses the formual LMN_PER= LMN* 27648/100

basically LMN_PER converts engineering units to units that the digital to analog converter understands.