hi, is there someone could help me? i have a task to control the return temperature from my factory to the chiller steady at 10C, i can control the pump for pumping more or less chilled water from chiller to the factory! i want to use PID to do this, i already put siemens PLC S7 300!

i want to use FB 58! but i don't understand how to interface my I/O with the program, i already read the PDF file, but i still don't understand! my input is temperature sensor from return water from factory (0 - 32767), and my output is decimal data for pump inverter speed (min :8500 , max:25000)!

please give me some advice!

 

Since you a trying to use an “FB” (in your case FB58) it means you already have a program written for this application. (Just in case you don’t know, FBs are custom written subroutines and they are not Siemens standard subroutines.) In this case the only help you can get is from your supplier / programmer. He must provide you the required information (documentation or direct).
I really don’t see how somebody else can help you.

If you want, archive the program and e-mail it to me ([email protected]). I will take a look to see how the I/O modules are interfaced with the code. Maybe I can see an elementary mistake or something easy.

ValRo