Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

USING SFC20 for shifting data in DB (CPU317-2PN/DP)

Created by: mechatronic at: 10/14/2010 8:28 AM (3 Replies)

Rating (0)

Thanks 0

4 Entries

10/14/2010 8:28 AM	Rate (0)
mechatronic Posts: 8 Rating: (0)	Hello! I want to use SFC20 for data shifting in DB ----------------------------------------------------------------------- ----------------------------------------------------------------------- STL: Call sfc20 SRCBLK :=P#DB3.DBX2.0 BYTE 602 RET_VAL:=#Temp1 DSTBLK :=P#DB3.DBX42.0BYTE 602 ----------------------------------------------------------------------- ----------------------------------------------------------------------- In PLCSIM and on CPU414-2DP it works ok and shifts data by 18 word blocks in entire DB. The problem is that in CPU 317-2PN/DP it only shifts data fromP#DB3.DBX2.0...P#DB3.DBX40.0 toP#DB3.DBX42.0...P#DB3.DBX80.0, but all otherP#DB3.DBX82.0...P#DB3.DBX120.0 &P#DB3.DBX122.0...P#DB3.DBX160.0 and so on, get the same data asP#DB3.DBX42.0...P#DB3.DBX80.0 has. No error codes are generated. Regards
mechatronic Posts: 8 Rating: (0)	Last edited by: mechatronic at: 10/14/2010 8:29 AM Last edited by: mechatronic at: 10/14/2010 8:28 AM
Suggestion To thank Quote Answer

10/14/2010 8:47 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 9/17/2024 Posts: 3020 Rating: (1054)	Hello mechatronic I'm actually surprised that SFC20works correctly in an S7-400 (or PLCSIM which behaves like a 400), since the rule is that the destination and target area's must NOT overlap (see HERE as well as HERE for more). Possibly not the news you wanted to hear but I hope it helps anyhow.
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
Suggestion To thank Quote Answer

10/14/2010 8:57 AM	Rate (0)
mechatronic Posts: 8 Rating: (0)	Actually it also works in PLCSIM configured as 317-2DP/PN. In CPU414-2DP I use SFC20 shifting like this in many places for production and related data monitoring. So is there any better solution? I also added my automated test to run on PLCSIM. Regards Attachment Test.zip (117 Downloads)
mechatronic Posts: 8 Rating: (0)	Last edited by: mechatronic at: 10/14/2010 10:04 AM Last edited by: mechatronic at: 10/14/2010 9:24 AM
Suggestion To thank Quote Answer

10/14/2010 9:25 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 9/17/2024 Posts: 3020 Rating: (1054)	mechatronic Actually it also works in PLCSIM configured as 317-2DP/PN. I'm not suprised about this, PLCSIM doesn't care what CPU you configured, it always behaves like an S7-400. About a better (or working) solution, I can only suggest some links for you (I presume you essentially need a FIFO buffer), which may contain what you need or at least serve as a starting block to develop your own block (if not it won't hurt to search for more yourself): FIFO with Array of UDT FIFO with S7 300 P.S: Even though I believe when you say that it works with an S7-400, you are technically relying on an "undocumented feature" for it to work, so perhaps worhtwhile coming up with a different solution anyhow. I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on