Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

Positive edge not working in cyclic interrupt

Created by: GiovanniRegas at: 3/17/2014 4:44 PM (17 Replies)

Rating (2)

Thanks 1

Result pages:: |; 1 | 2; |

18 Entries

Entries per page: 10 | all

3/19/2014 1:56 PM	Rate (0)
Marko Bursic Platinum Member Joined: 9/8/2009 Last visit: 7/17/2023 Posts: 1410 Rating: (153)	If you can't use a hardware interrupt, then yes, calculate the flank functionas described, each cyclic intr. scan, it shall work.

Suggestion To thank Quote Answer

3/20/2014 10:03 AM	Rate (0)
fritz Diamond Member Joined: 10/7/2005 Last visit: 1/17/2025 Posts: 3030 Rating: (1058)	GiovanniRegas Actually this is also my conclusion: -\|P\|- doesn't work on interrupt cycle but I would be more confortable on reading this in some kind of official manual. So would I dear GiovanniRegasas it goes against everything I know about Siemens PLC's. Saying that, haven't triedthis with TIA Portal and/or S7-1200(yet) so my questions are: 1.) What type of S7CPUis in use? 2.) What firmware does yourCPUhave? I urge you to send you findings via offical Support Requestto Siemens and keep us informed about what they advice.
	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

3/20/2014 4:05 PM	Rate (0)
Marko Bursic Platinum Member Joined: 9/8/2009 Last visit: 7/17/2023 Posts: 1410 Rating: (153)	Come on fritz, probably the problem is somewhere else. Giovanni, I took a look on your picture, one big fat warning: You are using a global datablock bit, and I would think that you are not updating the input at the interrupt. Also you would need to use peripheral adsress of your input (with :P), not theimage, in few words you need to update the state of inputs at each intr. call, that will slow your plc a bit.

Suggestion To thank Quote Answer

3/20/2014 4:26 PM	Rate (0)
Marciano Bronze Member Joined: 4/30/2007 Last visit: 3/9/2023 Posts: 231 Rating: (23)	GiovanniRegas are you sure that your program is not updating (zeroing) that DB1 area after updating from your Inputs?

Suggestion To thank Quote Answer

3/20/2014 4:36 PM	Rate (0)
kriipc Silver Member Joined: 4/11/2011 Last visit: 10/7/2024 Posts: 132 Rating: (7)	Marko Bursic Giovanni, I took a look on your picture, one big fat warning: You are using a global datablock bit, and I would think that you are not updating the input at the interrupt. Also you would need to use peripheral adsress of your input (with :P), not theimage, in few words you need to update the state of inputs at each intr. call, that will slow your plc a bit. Hello !? May be my post was to short to notice? kriipc Change DB1.DBX7612.1 to the actual input address. Marciano GiovanniRegas are you sure that your program is not updating (zeroing) that DB1 area after updating from your Inputs? Thats my point. Why so many words. Try it. If it works - good, If not - try other things.
	Last edited by: kriipc at: 3/20/2014 4:43 PM I'm just a human. Mistakes are allowed. Sorry for my english. Only 3 months of training and manuals :)
Suggestion To thank Quote Answer

3/21/2014 9:24 AM	Rate (0)
GiovanniRegas Posts: 16 Rating: (0)	Marko Bursic Come on fritz, probably the problem is somewhere else. Giovanni, I took a look on your picture, one big fat warning: You are using a global datablock bit, and I would think that you are not updating the input at the interrupt. Also you would need to use peripheral adsress of your input (with :P), not theimage, in few words you need to update the state of inputs at each intr. call, that will slow your plc a bit. I cannot read the peripheral address because it comes from a multiplexer. Every DI of my PLC can be set to be the pulse input, so I'm multiplexing all of them into the one in the global DB. But regardless the solution, I still can't get what the problem is. I mean, if the DB is updated with main loop timing, so slower than the interrupt, I should read less pulses than reality, not more. Or in other words, data doesn't keep its value until next update?
GiovanniRegas Posts: 16 Rating: (0)
Suggestion To thank Quote Answer

3/21/2014 9:25 AM	Rate (0)
GiovanniRegas Posts: 16 Rating: (0)	Marciano GiovanniRegas are you sure that your program is not updating (zeroing) that DB1 area after updating from your Inputs? My program surely not
GiovanniRegas Posts: 16 Rating: (0)
Suggestion To thank Quote Answer

3/21/2014 9:31 AM	Rate (0)
GiovanniRegas Posts: 16 Rating: (0)	fritz GiovanniRegas Actually this is also my conclusion: -\|P\|- doesn't work on interrupt cycle but I would be more confortable on reading this in some kind of official manual. So would I dear GiovanniRegasas it goes against everything I know about Siemens PLC's. Saying that, haven't triedthis with TIA Portal and/or S7-1200(yet) so my questions are: 1.) What type of S7CPUis in use? 2.) What firmware does yourCPUhave? I urge you to send you findings via offical Support Requestto Siemens and keep us informed about what they advice. I'm using a CPU 1214C DC/DC/DC, firmware v3.0
GiovanniRegas Posts: 16 Rating: (0)
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on