3/8/2011 9:48 AM | |
Joined: 5/4/2009 Last visit: 5/28/2024 Posts: 914 Rating: (40) |
Dear hdhossieni, I have two more questions if you don't mind, 1. on the FB58 itself in OB35 can we assign just a part of inputs and outputs (for example PV_PER and LMN_PER) and leave the others without any assignment? second question can be found in the following thread If we used STL, does it mean that we should only use absolute addressing?. I am really greatfull for your support.
|
Last edited by: O_Moderator at: 3/9/2011 9:30 AMnew subject after aplitting Aim Higher |
|
3/9/2011 6:26 PM | |
Joined: 5/4/2009 Last visit: 5/28/2024 Posts: 914 Rating: (40) |
OK, Is it legal if I did this? (please see attached) Warm regards. Tomy.
|
Aim Higher |
|
3/9/2011 9:02 PM | |
Joined: 1/28/2009 Last visit: 10/11/2024 Posts: 6852 Rating: (1365) |
For using the function as you done in attachment, you can follow these code as some requirement to use external signals.Also check the attachment for the reason.Please check other values for PV_PER. In the case the value is 2 the input value fed to algorithm is calculated like: (IW100*100)/27648. So the input value is considered to be 0 to 100. If you have different engineering high and low values , you need to work on PV_FAC.If your sensor reads values between 0 to 10 of a process variable , you just need to set PV_FAC=0.1.Please read this part of manual carefully. [code] L 1.000000e+000 T DB58.DBD 60 //PV_FAC T DB58.DBD 68 //LMN_FAC L 0.000000e+000 T DB58.DBD 64 //PV_OFF T DB58.DBD 72 //LMN_OFF L 2 T DB58.DBW 88 //PV_PER SET = DB58.DBX 90.0 //PV_PER_ON CALL "TCONT_CP" , DB58 PV_IN := PV_PER :=IW100 DISV := INT_HPOS:= INT_HNEG:= SELECT := PV := LMN := LMN_PER :=QW100 QPULSE := QLMN_HLM:= QLMN_LLM:= QC_ACT := CYCLE := CYCLE_P := SP_INT :=MD4 //SET FLOAT MAN := COM_RST := MAN_ON :=[/code] Please note that you can process the physical values outside the PID algorithm.For doing so you can try FC105(SCALE) and FC106(UNSCALE). You can find these function in LIBRARIES->STANDARD LIBRARIES->TI S7 CONVERTING BLOCKS.Check these function by reading the STEP7 online help which is available by selecting the function and pressing <F1>. BR hdhosseini AttachmentPER.zip (281 Downloads) |
Follow us on