Description of device parameters
Proline Promag 300 Modbus RS485
152
Hauser
Additional information
Options
Picklist
ASCII
option:
• 0 =
Even
option
• 1 =
Odd
option
Picklist
RTU
option:
• 0 =
Even
option
• 1 =
Odd
option
• 2 =
None/1 stop bit
option
• 3 =
None/2 stop bits
option
Byte order
Navigation
Expert → Communication → Modbus config. → Byte order (7113)
Description
Use this function to select the sequence in which the bytes are transmitted. The
transmission sequence must be coordinated with the Modbus master.
Selection
• 0-1-2-3
• 3-2-1-0
• 1-0-3-2
• 2-3-0-1
Factory setting
1-0-3-2
Additional information
Description
The byte sequence is not standardized by the Modbus protocol. However, if the host
system and the measuring device do not use the same byte sequence, correct data
exchange is not possible.
Changing the byte sequence in the host system often requires a extensive knowledge and
significant programming efforts. Hauser introduced the
Byte order
parameter
(→ 152) for this reason.
This makes it possible to use the standard settings of the host system and change the byte
sequence on the measuring device by trial and error. If correct data exchange cannot be
achieved by changing the byte sequence, the settings for the byte sequence of the host
system must be adapted accordingly.
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 (→ 152).
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)
Summary of Contents for Proline Promag 300
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