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| 9/14/2011 11:21 AM | |
Joined: 10/7/2005 Last visit: 9/2/2025 Posts: 3049 Rating:
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Hello micron_761 I fear your PID parameters are not correct. A Gain of 100 sounds very excessive and an Integral Time of 18ms and Derivative of 4 ms rather short. Questions: 1.) How did you determine that the original S5 Gain valueofP=100 means 100.0? My guess is that the Integer value of 100 does have "superimposed" decimal points andis evaluated aseither 10.0 or 1.00 or even 0.100 2.) How did you determine that the original S5 Integral (I=18) and Derivative values (D=4) are in ms? I suspect that the original values are in seconds. 3.) Is the original S5 FB80 protected or can you open itand evalute its logic? If it is not protected, please upload your original S5 program here for evaluation. Note too that sincea 115U (941-944 CPU) contains OB251 for PDI control, perhaps this FB80 is just a custom programmend calling shell for it in which casechapter 11 in the S5-115U Programmable Controller manual is where you shouldfind your answers. The only other FB80 PID reference I'm aware of isSIEPID related in which case the SIEPID S5 System Identification and Setting of PID Controllers manualis worth a read. I hope this helps and please let us know what you find. |
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| 9/14/2011 4:36 PM | |
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Posts: 13 Rating:
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Thanks Mr fritz / Marcjan Ans: 1.) I just put this value from S5 value *) As you suggested I read SIEPID S5 System Identification and Setting of PID Controllers 3.) S5 FB80 is as follows : ; NAME: REGLI DECL: I-DB B DECL: A-DB B DECL: AUTO IBI DECL: W IW DECL: X IW DECL: HA IW DECL: P IW DECL: I IW DECL: D IW DECL: Y QW A =AUTO = F 250.0 NOP 0 A F 0.1 R F 250.1 R F 250.2 R F 250.3 R F 250.4 S F 250.5 R F 250.6 R F 250.7 DO =A-DB L FY 250 T DR 11 NOP 0 DO =I-DB L =W L =X DO =A-DB T DW 22 TAK T DW 9 DO =I-DB L =HA L =P DO =A-DB T DW 1 TAK T DW 12 DO =I-DB L =I L =D DO =A-DB T DW 7 TAK T DW 5 NOP 0 L DW 48 DO =I-DB T =Y BE |
Last edited by: micron_761 at: 9/21/2011 6:54 PM |
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| 9/15/2011 3:55 AM | |
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Joined: 10/7/2005 Last visit: 9/2/2025 Posts: 3049 Rating:
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Hello micron_761 all your FB80 does is to copy the assigned Parameter values to a(most likely OB251 related) PID DB. "P" (Gain) for example is copied into DW 1, "I" is copied into DW 7, "D" is copied into DW 5 etc. As such I presume you will have an OB251 PID in use somewhere in your S5 program whichuses that DB. Please check your program for OB251 calls and what DB's are used for each OB251 call to verify the above presumtion. If OB251 is in use (as I would expect to be the case), havea look at chapter 11.2.3 of the previously mentioned S5-115U Programmable Controller manualwhich contains the "scaling" or "normilisation" factors for the values (e.g. Gain is multiplied with 0.001, so your value of 100 is in fact a Gain of 0.1, D is normalised via the Sampling interval Time TA etc.). Have a look too at the Converting Control Parameters from S5 to S7FAQ in this case which has more info on that subject. I hope this helps |
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