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Swapping of Floating point

Created by: AnsuAbinesh at: 3/15/2011 6:14 AM (13 Replies)

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3/15/2011 6:14 AM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear Experts, I want to know how to swapp 32-bit flaoting point value.Can i have a any instruction for that swapp. Kindly give us solution. Thanks in advance.

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3/15/2011 12:58 PM	Rate (0)
Aret Posts: 2348 Rating: (248)	Don't understand completely what you mean, but for swapping there are instructions CAW (word lenght) and CAD (dword length).
Aret Posts: 2348 Rating: (248)
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3/16/2011 10:12 AM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear Aret, Here i have 32bit floating point from em6400 conzerv modbus meter.Iam getting follwoing formatABCD 1.A -byte 1 2.B -byte 2 3.C -byte 3 4.D -byte 4 I want to know how toswap following combination. 1.BADC 2.CDAB 3.DCBA Can i have sample programm for above mentioned the same?.... Kindly give us solution Thanks in advance....
	Last edited by: Ganesan_K at: 3/16/2011 10:58 AM Last edited by: Ganesan_K at: 3/16/2011 10:14 AM
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3/16/2011 1:27 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 3/2/2021 Posts: 10452 Rating: (2212)	Hello Ganesan; Since ABCD are successive bytes (indside a DWord register address), the esiest way to do your byte swapping would be to copy the bytes to another 32-bit register in the order required. Say your ABCD bytes are in address MD100 bytes 100 to 103), and you want BADC in MD104 (bytes 104 to 107). Move MB100 (A)to MB105. Move MB 101(B) to MB104. Move MB 102 (C) to MB107. Move MB 103 (D)to MB 106. If you now look at MD 104, you will find it contains BADC. If this operation has to be carried out over a number of values, you could generate a FC that would take as inputs the source and destination addresses, calculate the correct byte addresses to move, and output the final word order in the destination address. Hope this helps, Daniel Chartier

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3/18/2011 9:34 AM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear dchartier, Thanks for your reply. Now my problem has been solved.

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3/31/2011 2:22 PM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear dchartier, i didAs per your mail.But icouldnot getting actual value in MD104 instead of I am getting MD106. ABCD(Real) are successive bytes.I have swap CDAB A-MB101 = C-MB106 B-MB102 = D-MB107 C-MB103 = A-MB104 D-MB104 = B-MB105 Am i correct or wrong?....

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3/31/2011 2:38 PM	Rate (0)
Chilly_Garfield Bronze Member Joined: 12/1/2010 Last visit: 10/13/2020 Posts: 316 Rating: (37)	For a good programming, don't cross the both data areas! In you text you have a fault, because you overwrite the MB104 and in the next line you want to read , I think, the old value. I think use the example from dchartieror use this: MD104 and MD 108. --> A-MB101 = C-MB110 B-MB102 = D-MB111 C-MB103 = A-MB108 D-MB104 = B-MB109
	Last edited by: Chilly_Garfield at: 3/31/2011 2:40 PM Grüße / Regards / Salut / ciao / adiós / adieu / tchau Chilly Garfield
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4/1/2011 7:20 AM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear Chilly, Sorry typing mistake.I am getting floating value in Address MD100.Then i havemoved to addressMD104 following method. A-MB100 move to MB106-C B-MB101 move to MB107-D C-MB102 move to MB104-A D-MB103 move to MB105-B Then i seen in MD104 I am getting wrong value. When i seen inMD106 i am getting proper value. I didnt understand why iam not getting in address MD104 proper value?. Kindly give us solution

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4/4/2011 11:32 AM	Rate (0)
Chilly_Garfield Bronze Member Joined: 12/1/2010 Last visit: 10/13/2020 Posts: 316 Rating: (37)	Hi Ganesan_K, what value do you want to get? Please make an example with values! I test the swap. If you monitor MD100 and MD104 in Hex you will see, the function is working fine.
	Grüße / Regards / Salut / ciao / adiós / adieu / tchau Chilly Garfield
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4/4/2011 1:06 PM	Rate (0)
AnsuAbinesh Experienced Member Joined: 12/14/2010 Last visit: 10/8/2020 Posts: 112 Rating: (0)	Dear Chilly, Here i have used cp341 modbus master with conzerv EM6400 meter.in this meter i have read kwh value as real format.The real order format not matching with siemens side.Due to that i dit byte swapping. I did following logic for byte swapp. L DB204.DBB0 T DB100.DBB2 L DB204.DBB1 T DB100.DBB3 L DB204.DBB2 T DB100.DBB0 L DB204.DBB3 T DB100.DBB1 I have read kwh vaue in DB204.DBD0. Then i move to DB100.DBD0 Am i correc or wrong? but iam not getting proper value in DB100.DBD0 instead of iam getting in DB100.DBD2 Can i have any swapp block if you have?.. Kindly give us solution Thanks in advance.
	Last edited by: Ganesan_K at: 4/4/2011 1:08 PM
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