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SOLVED> Is it allowed to have coils without contacts?

Created by: William_B at: 11/4/2011 12:52 PM (3 Replies)

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11/4/2011 12:52 PM	Rate (0)
William_B Posts: 5225 Rating: (1195)	Hi there! Please see attached the logic configuration I tried out on Step 7 Basic V11.0. Network 1. Two set coils in parrallel connected straight to the power bar - no contact. Network 2. Three set coils in series. Again there is no contact. The compiler has no problem with it. The question is if a PLC (S7-1200 / S7-300 / S7-400) would have a problem with it. I remember from Step 7 V5.1 that you could do STL code to do the same as in network 1, but this code could never get itself to translate to Ladder code. So.. is the code in these two networks acceptable? Attachment coils but no contacts.jpg (520 Downloads)
William_B Posts: 5225 Rating: (1195)	Last edited by: William B. at: 11/4/2011 2:29 PM Title: SOLVED
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11/4/2011 1:05 PM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 10/17/2024 Posts: 5697 Rating: (715)	Hello In Step7 v5 there are some rules to present the program inLAD or FBD, that is just for showing the networks on the screen, the PLC don't care about that if it compiles and download it's o.k. for the PLC. Here a link to explain a bit about it: https://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=21952992&caller=view Scroll a bit down. So if the compiler accepts your code it's o.k. to do it. 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 1 thankful Users William_B

11/4/2011 1:59 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 11/8/2024 Posts: 15388 Rating: (2443)	There are some program blocks which require something like a contact between the block and the power rail of the ladder logic. I just insert an always_on or always_off NO contact. Compile and if it(TIA Portal)does not complain, none is needed.
	science guy
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This contribution was helpful to 1 thankful Users William_B

11/4/2011 2:32 PM	Rate (0)
William_B Posts: 5225 Rating: (1195)	This method goes against my "old school" training. It is all good if the compiler accepts it. Thanks to both of you who responded. --William
William_B Posts: 5225 Rating: (1195)
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