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time difference

Created by: ZR_EC at: 1/22/2010 3:24 PM (6 Replies)

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1/22/2010 3:24 PM	Rate (0)
ZR_EC Posts: 5 Rating: (0)	Hello everyone, how can I calculate time difference between two DT variables in milliseconds? Difference may greater than one year.
ZR_EC Posts: 5 Rating: (0)
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1/23/2010 2:10 AM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Hello ZR_EC , Please read this thread carefully. Best regards. H-H

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1/23/2010 3:26 PM	Rate (0)
ZR_EC Posts: 5 Rating: (0)	Thank you very much! I wrote my own program to calculate the time difference that are greater than 25 days (ie 3555 days). Now I have to convert the time difference (ie 3555 days) in millisecond format (integer format), but I do not know how, because this number is higher than long integer format.
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1/24/2010 12:52 AM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Hello ZR_EC, It's very hard because the limit of a 32 bit DINT data type is L#+2147483647 while you need to register L#+307152000000. I hope some programming masters would tell you how to deal with such problem but are you sure that you want to count more than 9 years in msec ? I'm afraid that this might not be the task for an industrial 32-bit controller (PLC). Best regards. H-H

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1/26/2010 7:17 PM	Rate (0)
ZR_EC Posts: 5 Rating: (0)	Dear H-H, I need to synchronize the time of the protective terminal GE - MIF II with Simatic S7-400 through Modbus/TCP protocol. Basic time is 1/1/1996. In particular Modbus registers, I have to enter the elapsed time from 1/1/1996 until synchronization in milliseconds. Best regards
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9/11/2020 11:24 AM	Rate (0)
ArtemC Regular Member Joined: 2/2/2017 Last visit: 8/18/2022 Posts: 6 Rating: (0)	1 sec = 1000 ms 1 min = 60 sec = 60000 ms 1 hour = 60 min = 3600 sec = 36000000 ms 1day = 24 hours = 1440 min = 86400 sec = 86400000 ms 3555 days = 3,07152e+11 ms 3,07152e+11 < real maximum 3,402823e+38 >>> for calculations you need operations with real values Attachment real_40.gif (142 Downloads)
	Last edited by: AutoGen_3027862 at: 09/11/2020 11:38:14 Last edited by: AutoGen_3027862 at: 09/11/2020 11:41:48
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9/11/2020 12:03 PM	Rate (0)
qwazee Platinum Expert Joined: 3/30/2020 Last visit: 11/8/2024 Posts: 4938 Rating: (1010)	AutoGen_3027862 1 sec = 1000 ms 1 min = 60 sec = 60000 ms 1 hour = 60 min = 3600 sec = 36000000 ms 1day = 24 hours = 1440 min = 86400 sec = 86400000 ms 3555 days = 3,07152e+11 ms 3,07152e+11 < real maximum 3,402823e+38 >>> for calculations you need operations with real values You are making a bad suggestion to a very old topic. It is important that you understand the nature of REAL numbers to understand the why. Simply - a REAL number is an approximation which do not represent all possible numbers. See the attached for a simple demonstration. Attachment add-1-to-big-real.png (177 Downloads)
	Activities of this user is voluntary. There is no obligation or liability placed on this user. Though optional, your 'please' and 'thank you' is highly valued.
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