Skip to Content

Register Login

Default Header

(header konnte nicht geladen werden)

Navigation

Subroutine output

Created by: danfenton at: 8/4/2009 5:22 PM (7 Replies)

Rating (0)

Thanks 2

8 Entries

8/4/2009 5:22 PM	Rate (0)
danfenton Posts: 12 Rating: (0)	Hi, I'm just getting used to Step 7 so sorry for the newbie question. I'm having trouble getting an output bit from the subroutine in my program to actually come on physically on the PLC. The code worked fine in OB1 but i moved it into a subroutine and now it won't work. I've monitored the status in runtime and everything in the subroutine is working as it should but the output bit isn't working. Should i have edited the Local Variable Table somehow to allow it to output from a subroutine? Thanks Dan
danfenton Posts: 12 Rating: (0)
Suggestion To thank Quote Answer

8/4/2009 5:43 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 12/22/2025 Posts: 703 Rating: (98)	Hello, no it should work the same way in the subroutine as in the OB1. If the block is called and you monitored the right assigning of the output it seem that the same output is rewritten somewhere else. Use rightclick on it and choose "Go to -> Location..." (Ctrl+Alt+Q). The small table will open with the list of using this variable. Another solution is to open the Reference Data, editor menu Options -> Reference Data -> Display (Ctrl+Alt+R), the editor will open, inside choose the Assignment. In the table you'll see the used outputs, cross means bit access, eventually line on the right means byte, word or doubleword access. Regards Sydney

Suggestion To thank Quote Answer

8/4/2009 5:48 PM	Rate (0)
danfenton Posts: 12 Rating: (0)	Hi, The same output is used in two different subroutines, is this allowed? This is the only other place where it is used however at one time only one of the two subroutines will be in use. Thanks Dan
danfenton Posts: 12 Rating: (0)
Suggestion To thank Quote Answer

8/4/2009 6:04 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 12/22/2025 Posts: 703 Rating: (98)	It is allowed, but little bit strange and possibly wrongly used. The output bit in user code you assign in the process image in the CPU, the process image is written to real outputs after finishing the OB1. So if you assign the output bit more times, the last value is stored in the process image and also written to real output when the OB1 finishes. Regards Sydney

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users danfenton

8/4/2009 8:14 PM	Rate (0)
danfenton Posts: 12 Rating: (0)	I see what you're saying, basically my program must execute a certain code to switch on a light (and make it flash etc. etc.) when a motor is either running or not running. It is the same light however it operates in a different way. So supposing the problem is with the output being in different states in two different subroutines how could i get around this easily? Thanks for your help. Dan
danfenton Posts: 12 Rating: (0)
Suggestion To thank Quote Answer

8/4/2009 10:47 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 12/22/2025 Posts: 703 Rating: (98)	In this case you'd better to assign the output just in one location, make the logic with one BOOL result which you assign to the desired output. Depends on how is the logic and which language you use, probably the logic would be based on the OR instruction with combined parts, for example an easy logic in STL: A sigRun A blinker ON sigRun = Qx.x (in stop the output is powered, in run is flashing) Regards Sydney

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users danfenton

8/4/2009 10:53 PM	Rate (0)
danfenton Posts: 12 Rating: (0)	Right I understand, thanks for your help it was very much appreciated! Regards Dan
danfenton Posts: 12 Rating: (0)
Suggestion To thank Quote Answer

8/4/2009 11:40 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 12/22/2025 Posts: 703 Rating: (98)	You're welcome Regards Sydney

Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on