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PID CONT_C FB41

Created by: haris_usama at: 1/8/2014 8:08 AM (5 Replies)

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6 Entries

1/8/2014 8:08 AM	Rate (0)
haris_usama Posts: 81 Rating: (2)	Dear All, I have been trying to configure a PID CONT_C block FB41 but cannot make it work. I call the block in OB35, set the Cycle time to 100ms => which is the same as the OB35 Cycle time mentioned in the cyclic interrupts in the CPU configuration. I am using s7-300 314. I give the SP as 50.0, give PV = 20.0 (from PLC SIM) and try to read the output but get "0". It gives me effective PV and error correctly and also individual components of P,I (Since I am only using a PI controller and not derivative action). I have downloaded the program, including the DB. Is there something wrong that I am doing? Regards, Haris
haris_usama Posts: 81 Rating: (2)
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1/8/2014 9:49 AM	Rate (1)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 11/18/2024 Posts: 5697 Rating: (715)	Hello, Maybe you forgot to initialize the PID. This can be done in 2 ways. In the startup OB (100) enable manual mode with setpoint 0. or in program if you don't need the PID put it in manual mode with setpoint 0 You can also find a nice collection of examples created by our Friend Hd Hosseini here Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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This contribution was helpful to 2 thankful Users haris_usama RIAN Che

1/8/2014 9:54 AM	Rate (1)
S7 AUTOMAN Posts: 515 Rating: (56)	haris_usama Dear All, I have been trying to configure a PID CONT_C block FB41 but cannot make it work. I call the block in OB35, set the Cycle time to 100ms => which is the same as the OB35 Cycle time mentioned in the cyclic interrupts in the CPU configuration. I am using s7-300 314. I give the SP as 50.0, give PV = 20.0 (from PLC SIM) and try to read the output but get "0". It gives me effective PV and error correctly and also individual components of P,I (Since I am only using a PI controller and not derivative action). I have downloaded the program, including the DB. Is there something wrong that I am doing? Regards, Haris hi, if you want an output at the PID block manually, Set the "MAN_ON" parameter active and feed a desired value at "MV" and if you want to control it automatically, remove "MAN_ON", enable "P_SEL" and "I_SEL" and also feed the "GAIN" and "TI" values. it will just simply work
S7 AUTOMAN Posts: 515 Rating: (56)
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This contribution was helpful to 1 thankful Users haris_usama

5/18/2015 4:47 PM	Rate (0)
Min_Moderator Platinum Member Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4766 Rating: (122)	New question published by tomnass is split to a separate thread with the subject Cont_c configuration. Best regards Min_Moderator

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2/28/2016 11:35 AM	Rate (0)
sameeh.helmy Posts: 1 Rating: (0)	Dear all, i am a beginner in using PLC and i want to make aprogram to control modulated valve (0-10)volt using a feedback sensor(4-20)ma using PID. it will be great if anyone can help me with example. thanks in advance
sameeh.helmy Posts: 1 Rating: (0)
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2/29/2016 12:03 AM	Rate (0)
grrrrrroooo Platinum Member Joined: 3/16/2015 Last visit: 10/10/2021 Posts: 1250 Rating: (173)	Search the forum for the following keywords: PID Scale 4-20

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