10/23/2012 3:35 PM | |
Joined: 9/27/2006 Last visit: 9/21/2024 Posts: 12282 Rating: (2684) |
Hello madnesssm; There are various descriptions of the PID function blocks available from different manuals, but in this case the simplest explanation can be seen rom the following FAQ: What should you watch out for when calling and assigning parameters to the controller functions in function blocks (S)FB41, (S)FB42 and (S)FB43? When using these blocks, please watch out for the following points. 1. FB 41 "CONT_C"
From the text above you can see that the MANvariable containsthe manual setpoint which the controller will apply when the Boolean tag MAN_ON is active (=True). So if you configure your OP to change the value of MAN_ON in your CONT_C block (by accessing the DB address of the tag) then you can switch the PID from Manual operation to Auto, and vice-versa. In Manual mode the value written to the MAN variable is the value the controller will output to the actuator of your loop. Hope this helps, Daniel Chartier |
10/23/2012 4:22 PM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating: (1365)
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Hello, Normally this happen when you have setpoint=0 and process value =0. When you work in a dynamic process, auto-->manual switchover is with bump! But note, manual to automatic switchover is guranteed bumpless internally.Please check the following link: FB58,Bumpless manual to automatic switchover
BUMPLESS PID
Best regards, Hamid Hosseini |
Last edited by: hdhosseini at: 10/23/2012 5:56 PMLast edited by: hdhosseini at: 10/23/2012 4:28 PM |
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10/23/2012 9:26 PM | |
Joined: 6/11/2012 Last visit: 12/3/2023 Posts: 38 Rating: (0) |
I solve mine problem. Tnx for help. BR! |
This contribution was helpful to1 thankful Users |
6/22/2020 6:58 AM | |
Joined: 6/19/2017 Last visit: 9/6/2024 Posts: 8175 Rating: (172) |
New question published by Kaviaaaaaaaan is split to a separate thread with the subject Can't equalize the manual and automatic values in the ID. Best regards |
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