SEW-Eurodrive DHR41B, Manual

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Manual – MOVI-PLC® advanced DHR41B for EtherNet/IP, Modbus/TCP and PROFINET IO
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8
Introduction
The Modbus Protocol (Modbus/TCP)
8.1.2 Services (function codes)
For process data exchange, parameter data exchange and unit identification, the
DHR41B option provides 4 FC.. services (
F unction C odes).
• FC 3 Read Holding Registers
• FC16 Write Multiple Registers
• FC23 Read/Write Multiple Registers
• FC43 Read Device Identification
The FC3 and FC16 services allow reading or writing of one or more registers. FC23 al-
lows a register block to be read and written simultaneously. FC43 can be used for a unit
identification by reading out the identity parameters.
8.1.3 Access
The implemented registers and possible services (function codes) for data exchange
are summarized in the following table.
Meaning when
Offset (hex) Reading Writing Access Comment
0 - 3 - - - Reserved
4 - FF Process input
data (actual val-
ues) Process output data
(setpoint values) FC3,
FC16,
FC23 0 - 64 words
100 - 103 - - - Reserved
104 - 1FF Process output
data (setpoint val-
ues) - FC3 For reading the setpoint values by
a client other than the controlling
one
200 - 2FF Result acyclical
parameter chan-
nel Request acyclical
parameter channel FC3,
FC16,
FC23 4 words
300 - FFFF - - - Reserved
Special
case: 219E
(8606
dec
)
Fieldbus timeout
interval, read
value Fieldbus timeout
interval, write value FC3, FC16 Parameter P819: 16-bit value, tim-
eout interval in ms
0 0
I