Basler DGC-2020 Instruction Manual page 222

The same byte alignments are required to write.
Long Integer Data Format (INT32)
The Modbus long integer data format uses two consecutive holding registers to represent a 32-bit data
value. The first register contains the low-order 16 bits and the second register contains the high-order 16
bits.
Example: The value 95,800 represented in long integer format is hexadecimal 0x00017638. This number
will read from two consecutive holding registers as follows:
Holding Register
K (Hi Byte)
K (Lo Byte)
K+1 (Hi Byte)
K+1 (Lo Byte)
The same byte alignments are required to write.
Floating Point Data Format
The Modbus floating point data format uses two consecutive holding registers to represent a data value.
The first register contains the low-order 16 bits of the following 32-bit format:
• MSB is the sign bit for the floating-point value (0 = positive).
• The next 8 bits are the exponent biased by 127 decimal.
• The 23 LSBs comprise the normalized mantissa. The most-significant bit of the mantissa is always
assumed to be 1 and is not explicitly stored, yielding an effective precision of 24 bits.
The value of the floating-point number is obtained by multiplying the binary mantissa times two raised to
the power of the unbiased exponent. The assumed bit of the binary mantissa has the value of 1.0, with
the remaining 23 bits providing a fractional value. Table B-2 shows the floating-point format.
Sign
1 bit
The floating-point format allows for values ranging from approximately 8.43X10
point value of all zeroes is the value zero. A floating-point value of all ones (not a number) signifies a
value currently not applicable or disabled.
Example: The value 95,800 represented in floating point format is hexadecimal 47BB1C00. This number
will read from two consecutive holding registers as follows:
Holding Register
K (Hi Byte)
K (Lo Byte)
K+1 (Hi Byte)
K+1 (Lo Byte)
The same byte alignments are required to write.
B-6
Value
hex 76
hex 38
hex 00
hex 01
Table B-2. Floating Point Format
Exponent + 127
8 bits
Value
hex 1C
hex 00
hex 47
hex BB
DGC-2020 Modbus™ Communication
Mantissa
23 bits
-37 38
to 3.38X10 . A floating-
9400200990 Rev I