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UDINT S7-300

Created by: Jens_app at: 8/14/2014 2:09 PM (11 Replies)

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8/14/2014 2:09 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 11/29/2024 Posts: 815 Rating: (123)	I have a signed double integer that holds the working time of my pump, the thing is when I exceed + 2 147 483 647 the count restarts at - 2 147 483 648. This really looks ridiculous when show on the HMI panel. Is there a way to get unsigned double integers in s7-300? I'd like to countfrom0 to4 294 967 295. Maybe some kind of workaround? Thanks in advance. Kind regards, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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8/14/2014 2:49 PM	Rate (0)
William_B Posts: 5225 Rating: (1198)	Jens_app I have a signed double integer that holds the working time of my pump, the thing is when I exceed + 2 147 483 647 the count restarts at - 2 147 483 648. This really looks ridiculous when show on the HMI panel. Is there a way to get unsigned double integers in s7-300? I'd like to countfrom0 to4 294 967 295. Maybe some kind of workaround? Thanks in advance. Kind regards, Jens Hi Jens, The trouble is rather with the display. If you display your DINT as a UDINT, then it will automatically diplay right even if the PLC would show it wrong. As alternative you could use DWORD which is a UDINT.. but the IEC checking function (if active) will complain about it. Compare functions will give you a problem though.. hopefully you do not have those. Let the Forum know if this is not enough for you.. then "somebody" can take a more complicated route. w
William_B Posts: 5225 Rating: (1198)
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8/14/2014 3:11 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 11/29/2024 Posts: 815 Rating: (123)	Hi William, thanks for your reply. First problem is you can not define UDINT tags in the tp700 panel. And DWORD is not really an option because of the comparison and math functions. I could start with convert functions, but thatwould be such ahassle. I'm looking for a more convinient approach. I was thinking about rescaling + 2 147 483 647 -> - 2 147 483 648 to 0 to 4 294 967 295, but that didn't work out. Any other suggestions are welcome. Thanks in advance
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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8/14/2014 3:18 PM	Rate (0)
William_B Posts: 5225 Rating: (1198)	Jens_app First problem is you can not define UDINT tags in the tp700 panel. And DWORD is not really an option because of the comparison and math functions. Surely you could assign the variable as DWORD on the TP700 as to correct the displayed number. Just make sure that you handle the math and compare functions in a good way in your PLC.. then the negative numbers will not matter as the overflow will provide "correct" answers. Else consider using REAL. w
William_B Posts: 5225 Rating: (1198)
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8/14/2014 3:25 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 11/29/2024 Posts: 815 Rating: (123)	William B. Jens_app First problem is you can not define UDINT tags in the tp700 panel. And DWORD is not really an option because of the comparison and math functions. Surely you could assign the variable as DWORD on the TP700 as to correct the displayed number. Just make sure that you handle the math and compare functions in a good way in your PLC.. then the negative numbers will not matter as the overflow will provide "correct" answers. Else consider using REAL. w Thanks for the repliesWilliam, real was my final option. I will proceed with that option. Kr, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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8/16/2014 9:05 AM	Rate (0)
uel123 Gold Member Joined: 1/29/2006 Last visit: 1/8/2025 Posts: 447 Rating: (64)	Hello! .. just because of my curiosity: are you counting operating time in miliseconds?? Do you really need such accuracy? 2^31 is a very big number. If you would be satisfied with seconds, you could count with DINT up to appr. 68 years! I am not sure, if any real industrial equipment would even last so long, that its operating hors counter would show 68 years! Have fun! uel123.

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8/16/2014 11:07 AM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 11/29/2024 Posts: 815 Rating: (123)	uel123 Hello! .. just because of my curiosity: are you counting operating time in miliseconds?? Do you really need such accuracy? 2^31 is a very big number. If you would be satisfied with seconds, you could count with DINT up to appr. 68 years! I am not sure, if any real industrial equipment would even last so long, that its operating hors counter would show 68 years! Have fun! uel123. Dear uel123, Thanks for your reply. Yes I need that accuracy. An 16bit integer wouldn't suffice in my case. Kind regards, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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8/16/2014 11:37 AM	Rate (0)
William_B Posts: 5225 Rating: (1198)	Jens_app Dear uel123, Thanks for your reply. Yes I need that accuracy. An 16bit integer wouldn't suffice in my case. Kind regards, Jens Jens, If a high accuracy is needed.. then REAL might not work for you. REAL can be like S5TIME in the sense that S5TIME can not give 12s345ms. You can loose some lower order numbers. Please reconsider your approach. w
William_B Posts: 5225 Rating: (1198)
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8/18/2014 8:42 AM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 11/29/2024 Posts: 815 Rating: (123)	[quote user="William B] Jens, If a high accuracy is needed.. then REAL might not work for you. REAL can be like S5TIME in the sense that S5TIME can not give 12s345ms. You can loose some lower order numbers. Please reconsider your approach. wHi William, I haven't explained myself well enough. I don't need an accuracy in miliseconds, but in seconds. It's just that a 16bit integer wouldn't be suffice in my case, 65535 seconds just isn't enough. A real will do the trick. Thanks Kind regards, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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8/18/2014 10:54 AM	Rate (0)
fritz Diamond Member Joined: 10/7/2005 Last visit: 1/17/2025 Posts: 3030 Rating: (1058)	Hello Jens_app I'm a bit confused, so allow me to hark back on this subject. If seconds accuracy is all you need and you count in seconds, uel123's advice is very valid as a DINT valueof + 2 147 483 647seconds is about 68 years which would surely suffice for a pump runtime. As you experience a wrap around of the DINT from + 2,147,483,647to - 2,147,483,648, I suspect though that you do indeed count in milliseconds, which then"only" gives you about 24 days for + 2,147,483,647ms. Question: Why not count your runtime in full seconds in a DINT and be happy that it will lastfor 68 years? As for the REAL option, I fear that it may fail as the precision for a REAL is about 6 decimal places (see How accurately can I calculate with REAL numbers that are used in extensive formulas? for more). Just in case counting in seconds and/or 68 years of runtime is not enough, I would make my own "Long DINT" counter that let's say counts up to 1Billion in oneDINT, resets that DINT back to zero and adds1 to a second DINT value that represents the Billion count value (and link both to the HMI and have two output fields side by side for the display of the "combined" value). 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.
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