System integration
Proline Promass F 100 Modbus RS485
48
9.2.2
Register information
For an overview of device parameters with their respective Modbus register
information, please refer to the "Modbus RS485 register information" section in the
"Description of device parameters" documentation .
9.2.3
Response time
Response time of the measuring device to the request telegram of the Modbus master:
typically 3 to 5 ms
9.2.4
Data types
The measuring device supports the following data types:
FLOAT
(floating point number IEEE 754)
Data length = 4 bytes (2 registers)
Byte 3
Byte 2
Byte 1
Byte 0
SEEEEEEE
EMMMMMMM
MMMMMMMM
MMMMMMMM
S = sign, E = exponent, M = mantissa
INTEGER
Data length = 2 bytes (1 register)
Byte 1
Byte 0
Most significant byte (MSB)
Least significant byte (LSB)
STRING
Data length = depends on the device parameter, e.g. presentation of a device parameter with a data length = 18
bytes (9 registers)
Byte 17
Byte 16
...
Byte 1
Byte 0
Most significant byte (MSB)
...
Least significant byte (LSB)
9.2.5
Byte transmission sequence
Byte addressing, i.e. the transmission sequence of the bytes, is not specified in the Modbus
specification. For this reason, it is important to coordinate or match the addressing
method between the master and slave during commissioning. This can be configured in
the measuring device using the
Byte order
parameter.
The bytes are transmitted depending on the selection in the
Byte order
parameter:
FLOAT
Sequence
Options
1.
2.
3.
4.
1 – 0 – 3 – 2 *
Byte 1
(MMMMMMMM)
Byte 0
(MMMMMMMM)
Byte 3
(SEEEEEEE)
Byte 2
(EMMMMMMM)
0 – 1 – 2 – 3
Byte 0
(MMMMMMMM)
Byte 1
(MMMMMMMM)
Byte 2
(EMMMMMMM)
Byte 3
(SEEEEEEE)
2 – 3 – 0 – 1
Byte 2
(EMMMMMMM)
Byte 3
(SEEEEEEE)
Byte 0
(MMMMMMM)
Byte 1
(MMMMMMM)
