5/18/2011 7:38 AM | |
Posts: 53 Rating:
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Hi, Attachmentpid.pdf (1390 Downloads) |
5/19/2011 12:26 AM | |
Posts: 53 Rating:
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Hi Aret, Thanks for your reply. Find attached the pdf of my code for the particular FC. We are controlling a steamcontrol valve to achieve the desired cooktemperature. The temperature setpoint for the is set from the HMI (db95.dbd74). network no 5 is to ensure the transition from Auto to manual is bumpless but not sure why it's not bumpless from manual to auto. please advise. Thanks, MS AttachmentFC52.pdf (1228 Downloads) |
5/19/2011 12:55 PM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating:
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Hi You have option of using Modular PID Control as a software package from SIEMENS.I think 3 function of this package would be helpful: 2.1.20 PID: PID Algorithm parameter SMOO_CHG ,smooth change over from the manual mode to the automatic mode. 2.1.23 ROC_LIM: Rate of Change Limiter Ramp functions are used when the process must not be subjected to a step change at the input. For example when the set point or gain of PID algorithm change suddenly(Jump in these crucial parameters). 2.1.13 LMNGEN_C: Output Continuous PID Controlle parameter LMNRC_ON ,manipulated value rate of change on,ensures bumpless switchover in manipulated variable. regards |
Last edited by: hdhosseini at: 6/1/2012 2:51 PM |
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5/20/2011 5:02 AM | |
Joined: 7/2/2008 Last visit: 8/26/2024 Posts: 928 Rating:
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Hello MS10, 1st make sure that auto mode resets manual bit and manual mode resets automatic bit. 2nd make sure that db102.dbw4 is the right word for valve position. If I may suggest, Try making it easy for yourself and use only one bit for automatic and manual and also use the output parameter LMN IF "DB_PID".COOK_TEMP_PID.Manual_Mode = 0 Movethe output parameter LMN to "DB_PID".COOK_TEMP_PID.Manual_CV Also as explained earlier by ARET, in manual mode it's better to transfer the process value to the setpoint So, IF "DB_PID".COOK_TEMP_PID.Manual_Mode = 1 Move the the output parameterPV to "DB_PID".COOK_TEMP_PID.Setpoint If you still face problems then It will be better if you upload your programhere somembers can check it for you. Best regards. H-H AttachmentFC52 with comments.pdf (885 Downloads) |
5/20/2011 10:26 PM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating:
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Hi See the attachment Attachmentrate_limiter.zip (1995 Downloads) |
Last edited by: hdhosseini at: 10/29/2011 4:23 PM |
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