Endress+Hauser Proline Promass E 300, Руководство по эксплуатации

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System integration Proline Promass E 300 Modbus RS485
70 Hauser
Compatible Modbus registers: diagnostic information
Diagnostic information Compatible Modbus registers
Diagnostic code (data type: String), e.g. F270 6821
Diagnostic number (data type: Integer), e.g. 270 6859
The Modbus registers are compatible but the diagnostic numbers are not. Overview of
the new diagnostic numbers →  150.
9.3 Modbus RS485 information
9.3.1 Function codes
Function codes are used to define which read or write action is carried out via the Modbus
protocol. The measuring device supports the following function codes:
Code Name Description Application
03 Read holding
register Master reads one or more Modbus
registers from the device.
A maximum of 125 consecutive
registers can be read with 1
telegram: 1 register = 2 bytes

The measuring device does
not make a distinction
between function codes 03
and 04; these codes therefore
yield the same result.
Read device parameters with read
and write access
Example:
Read mass flow
04 Read input
register Master reads one or more Modbus
registers from the device.
A maximum of 125 consecutive
registers can be read with 1
telegram: 1 register = 2 bytes

The measuring device does
not make a distinction
between function codes 03
and 04; these codes therefore
yield the same result.
Read device parameters with read
access
Example:
Read totalizer value
06 Write single
registers Master writes a new value to one
Modbus register of the measuring
device.

Use function code 16 to write
multiple registers with just 1
telegram.
Write only 1 device parameter
Example: reset totalizer
08 Diagnostics Master checks the communication
connection to the measuring device.
The following "Diagnostics codes"
are supported:
• Sub-function 00 = Return query
data (loopback test)
• Sub-function 02 = Return
diagnostics register