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TIP: PID (FB PID_Compact) V2.x (configured with STEP7 V12)
Created by: Denilson Pegaia at: 2/28/2013 11:16 AM (10 Replies)
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| 2/28/2013 11:16 AM | |
Joined: 9/23/2005 Last visit: 12/20/2024 Posts: 4373 Rating:
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Hi, Here there some tips about PID (FB PID_Compact)V2.x, configured with STEP7 V12 (/tf/WW/en/Posts/33957#top ) (for PID_Compact V3, see tips at https://support.industry.siemens.com/forum/br/pt/posts/simple-sample-and-tips-step-7-pid-pid-compact-v3-tia-v19/309119/?page=0&pageSize=10#!#post1178234) 1 – Documentation The main documentation about PID stay on: STEP 7 Professional V13 manual (http://support.automation.siemens.com/BR/view/en/89515142) Chapter 11.3 SIMATICS7-1200 Easy Book (http://support.automation.siemens.com/BR/view/en/39710145) Chapter 8) 2 - What’s news in version 2, compared with version 1.2: The STEP7 V12 online help shows a description of the changes of this new PID version: Online Help, Contends, Programming a PLC, References, References (S7-1200, S7-1500), Technology (S7-1200, S7-1500), PID Control (S7-1200, S7-1500), PID Compact (S7-1200, S7-1500), New features of PID_Compact (S7-1200, S7-1500). - Call the PID from a Cyclic Interrupt OB. The Cyclic time OB property should be faster as the controlled process and makes sense with the application: for a temperature control that have field variations in the order of seconds, make no sense times lower as 10ms or gather as seconds… The default value for a Cyclic Interrupt OB is 100ms and it is enough for the general (non time critical) applications. - Click in the toolbox button and set the PID parameters (details, see topic 3, Parameters).
4– Parameters Basic settings Controller Type / Physical Unity: it set units used in the representation of the others configuration parameters. There is no direct influence on the PID algorithm by itself. Reverse operation: It could be obtained with a check box (Invert the control logic – recommended procedure), or, like S7-200/300/400, with the use of a negative value of Proportional Gain. PID behavior after CPU restart: as default value for the PID configuration is set the PID to manual mode after restart. If it is desired that the PID follow different operation mode (for example runs in automatic mode after CPU restart) it is necessary to change the proprieties “activate Mode after CPU restart” / “Set Mode to”. Input / output parameters: Set point and process values (Setpoint and Input inputs) should be filled with same units (for example, it is not possible to have set point in Celsius and process value in Fahrenheit). However, e.g. there is no relationship between inputs units and outputs unit. Note, that the variable ManualValue should have the same unit as output. Process value settings Process value limits: High and low limits for the process values. If the process value violates these limits then the PID shows an error indication and reacts like configured in “output value settings”. Process value scaling: shows the unit conversion rules for analogical signals (only relevant if Basic settings/Input was configured to use Input_PER (analog)). Advanced settings Process value monitoring: it is used to set alarms bits. They should stay inside of the Process value limits range to be effective. If the process value violates Process value monitoring limits but says inside of the Process value limits, then the PID set alarms bits but still works. PWM limits: Has just significance if the PID is configured have a PWM output. These parameters avoid that the PWM “flicks” the output. Output value limits: used as limit for float points output and as scale conversion rules for analogical outputs. Reaction to error: here you specify how the PID reacts to an unexpected situation (e.g. input outside to configured limits, non regular time interval call or non valid float point input): goes to inactive mode, “freeze” the output while the error occurs (default value) or set to a substitute value while the error occurs. PID parameters: if is intended to tuning the PID automatically, this parameters are disable (default situation), else the Tuning Rule (that defines if the PID will runs with or without derivative control). For manual tuning, it should be enabled. The parameters should be set direct in the configuration tool or by instance DB variables (details in the topic 4, TIPs, at How to set PID parameters manually).
How to set PID parameters manually: To tuning the PID manually, it necessary to set the “Enable manual entry” property at PID block toolbox button -> Advanced settings -> PID Parameters. The PID tuning parameter could be found at this windows, or be accessed directly in the Instance DB (for example in a Watch Table or from a HMI) in this variables: Proportional Gain: “Instance DB name”.Retain.CtrlParams.Gain Derivative action Time: “Instance DB name”.Retain.CtrlParams.Td Derivative delay coefficient: “Instance DB name”.Retain.CtrlParams.TdFiltRatio Proportional action weighting: “Instance DB name”.Retain.CtrlParams.PWeighting Derivative action weighting: “Instance DB name”.Retain.CtrlParams.DWeinghting All PID parameters are retentive. If you enter the PID parameters manually, you must completely download PID_Compact (see online documentation topic “Downloading technology objects to device”). Alternative is set the parameter by watch table or to create another instance DB to the PID How to reset an inactive mode / how to set a mode The PID has many operations modes. The State output parameter shows the actual operation mode. There is also Application Examples at: Controlling simulated controlled systems in S7-1500 with PID_Compact V2
AttachmentSample PID 1500 V12.zip (2839 Downloads) |
Last edited by: Pegaia at: 7/11/2014 5:42 PMLast edited by: O_Moderator at: 3/14/2013 1:35 PMLast edited by: Pegaia at: 3/6/2013 2:24 PMLast edited by: Pegaia at: 3/1/2013 11:22 AMLast edited by: Pegaia at: 2/28/2013 11:25 AMLast edited by: Denilson Pegaia at: 6/22/2015 1:31:12 PMLast edited by: Denilson Pegaia at: 11/29/2023 11:10:20Denilson Pegaia |
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| 3/13/2013 6:27 PM | |
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Joined: 9/23/2005 Last visit: 12/20/2024 Posts: 4373 Rating:
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Hi, Here there is a cast that shows how to work with the demo project. Alternativaly, there is an official PID sample project at: http://support.automation.siemens.com/BR/view/en/79047707 Attachmentcast.zip (2092 Downloads) |
Last edited by: Pegaia at: 11/14/2013 6:00 PMLast edited by: O_Moderator at: 3/14/2013 1:36 PMDenilson Pegaia |
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| 6/4/2013 2:50 PM | |
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Posts: 123 Rating:
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Is the PID_Compact function better than CONT_C function? |
| 8/1/2013 11:54 AM | |
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Posts: 26 Rating:
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Should the V2.0 block be available for the 1200? I only have it for 1500priject, In a 1200 project i can only access V1.2 pid compact block |
| 11/10/2013 2:34 PM | |
Joined: 9/14/2012 Last visit: 11/8/2024 Posts: 2 Rating:
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PID Compact can cascade composed of Double Cross Burning Control System？ |
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