S7-300 fb41 cont_c pid block

[tulip]

HI.I REVIEWED A PROJECT DONE. THIS FB41 PID BLOCK WAS USED FOR THE PASTEURIZATION PROCESS. THE PROCESS I CAN'T UNDERSTAND IS THE ACTION. WHILE THE SYSTEM IS IN HAND, THE LMN VALUE OF FB41 BLOCK IS ASSIGNED TO I_ITLVAL. ALSO, IF INTEGRAL VALUE ( TI ) is ZERO, I_ITL_ON INPUT HAS BEEN ACTIVATED. IF THE SYSTEM IS AUTOMATIC AND THE INTEGRAL VALUE IS DIFFERENT FROM ZERO ( I_ITL_ON=0), IT HAS ASSIGNED LMN_I VALUE TO I_ITLVAL. I WOULD LIKE TO INFORM ME ABOUT IT. THANKS IN ADVANCE..

 

[tulip]

Or should i ask. What is the task of i_itl_on and i_itlval inputs? Also what does it mean for i_itl_on=0 or i_itl_on=1 when i_sel =1?

 

[Thomas_v2]

It initializes the value of the internal integrator. I guess it's done for bumpless changeover from manual to auto mode. Which is not neccessary if someone sets MAN_ON to true, then the same is done internally (integrator is set to a value, that the controller continues with the current MAN value).

If your installation of step7 was correct, you can select the FB41 block and press F1. The help of the block should pop up where all paramaters are described.