Siemens S5/S7 Floating-Point Formats

Does anyone have a description of the Siemens S5 and S7 floating-point
formats? A web search finds a conversion library at
formatting link
which I could buy, but I
don't need all the other functions it contains.
Reply to
Chris Doran
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The S7 floating point format is IEEE, big endian format. I don't know what format the S5 uses.
Reply to
Peter Nachtwey
Hi, Wellcome to the number formats... it has been several years when I made this but if I remember well: S7 follows IEEE754 standard S5 is a non-normalized single precision floating point (0,xx)
The formats are: (from bit 31 to bit 0)
S7 : [S 2^7 ... 2^0 2^-1 .... 2^-23] Bits Content --------------- 31 Sing of mantisa (1 bit) 30-23 Exponent (8 bits) 22-0 Mantissa of fraction (23 bits)
S5: [SE 2^6 ... 2^0 SM 2^-1 ... 2^-23 Bits Content --------------- 31 SE: Sign of exponent (1 bit) 30-24 Exponent (7 bits) 23 SM: Sign of mantissa (1 bit) 22-0 Mantissa (23 bits)
Check also how the numbers are stored in both PLC's. They are in a different way.
I hope this is what you need, Cheers, Quique
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