5/19/2008 1:06 PM | |
Joined: 9/27/2006 Last visit: 9/2/2024 Posts: 12282 Rating:
|
Hello Jeffrey; |
This contribution was helpful to
48 thankful Users
|
10/22/2008 4:14 PM | ||||||||||||||||||||||||||||||||||||||||
Joined: 9/23/2005 Last visit: 8/27/2024 Posts: 4347 Rating:
|
FB and FC are two types of subroutines that make STEP 7 a very flexible and powerful tool.As subroutines, FC and FB can be used to optimize the programming. Main uses for FC and FB:
|
|||||||||||||||||||||||||||||||||||||||
Denilson Pegaia |
||||||||||||||||||||||||||||||||||||||||
This contribution was helpful to
43 thankful Users
|
10/23/2008 3:02 AM | |
Joined: 7/2/2008 Last visit: 8/26/2024 Posts: 928 Rating:
|
Great explanation from Daniel Chartier and beautiful table from Pegaia. Really good work. I can't add something but I would like tohighlight one of the differences (I consider it a big one). If you can use an FC with shared DB with Load and transfer, it's true that this would be very equal to the use of FB and instance DB. BUT still you can't ignore the story of parameters. In FB like Pegaia had said the actual parameters (INs and Outs) are transferred into and from the instance data block. (This increases your data block space) while if you use FC with shared data block you don't have to add a place for your parameters in the shared data block because the FC deals with the addresses of parameters. I think this might increase execution time in FB because FB have to copy Input actual parameters to formal parameters(inside instance data block) and also have to copy Output formal parameters (inside instance data block) to the actual parameters. However, this gives a really beautiful feature for FBs. Since the FB reserve space in the instance data block for parameters, You can ignore some parameters when you call this FB. I mean if you create FB with 10 inputs and 20 outputs, You can call this FB and ignore any parameter you don't need because the FB will take the initial value of this parameter in the instance data block. So you can select only the parameters you need and let the FB takes the initial of the other parameters. The best example for this story of parameters is the FB41 (PID controller). you don't have to assign actual parameters to the formal parameters of the FB41 and this is a good thing because you assign just what you need. Now we come to the FC, you can't ignore any parameters and you MUST assign actual parameters to all formal parameters you have in this FC. The attached file explains the FC,FB and the difference between them in better words that what I said. Best regards. AttachmentFC vs FB.pdf (6879 Downloads) |
Last edited by: H-H at: 10/23/2008 3:12 AM |
|
This contribution was helpful to
20 thankful Users |
10/24/2008 7:20 PM | |
Joined: 5/19/2006 Last visit: 8/15/2024 Posts: 548 Rating:
|
You can use "Monitor with Call-Up Path" to monitor a specific instance of an FB See STEP7 help on how to setup this mode. Dec Thank you billwest, that web link explains how to setup call-up path. You need to close "quote user" in order to highlight your answer from the quoted user messsage. http://support.automation.siemens.com/WW/view/en/21671563 AttachmentMonitor with Call-Up Path.zip (2241 Downloads) |
Last edited by: Dec at: 10/24/2008 7:56 PMLast edited by: Dec at: 10/24/2008 7:37 PMLast edited by: Dec at: 10/24/2008 7:33 PM |
|
This contribution was helpful to
4 thankful Users |
9/13/2013 12:09 PM | |
Joined: 9/1/2005 Last visit: 8/12/2024 Posts: 4104 Rating:
|
follow up question published by adammukhrizis split to a seperate thread with the subject FB or FC program which use 4 to 20ma to control pump with FC and FB method?. |
My Forum is the place to personalize your profile, |
|
5/23/2016 2:41 PM | |
Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4767 Rating:
|
New question published by luis schwenke is split to a separate thread with the subject FC in Tia Portal to set a solenoid. Best regards |
Follow us on