JUMO LOGOSCREEN nt Interface Description page 23

Double values
Example
When using Modbus, double values are also processed in the IEEE-754
standard format (32bits). Unlike float values, no bytes are swapped for double
values.
Double float format (32-bit) according to standard IEEE 754
SEEEEEEE
Byte 1
MMMMMMMM
Byte 5
S = sign bit
E = exponent (complement to base 2)
M = 52bit normalized mantissa
Modbus double format
Modbus address x
SEEEEEEE
Byte 1
Modbus address x+2
MMMMMMMM
Byte 5
Request the double value from address 0x0066, when this address contains
the value "1234567.89" (0x4132D687E3D70A3D in IEEE 754 format).
Request: 140300660004A6D3 (CRC16 = D3A6)
Response: 1403084132D687E3D70A3DE1C1 (CRC16 = C1E1)
Please check how double values are stored in your application. If necessary,
the bytes will have to be swapped accordingly in your program, after they have
been fetched from the paperless recorder.
4 Modbus protocol description
EEEEMMMM MMMMMMMM
Byte 2
MMMMMMMM MMMMMMMM
Byte 6
EEEEMMMM MMMMMMMM
Byte 2
MMMMMMMM MMMMMMMM
Byte 6
MMMMMMMM
Byte 3
MMMMMMMM
Byte 7
Modbus address x+1
MMMMMMMM
Byte 3 Byte 4
Modbus address x+3
MMMMMMMM
Byte 7 Byte 8
Byte 4
Byte 8
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