Supported Modbus Functions - Siemens SIPROTEC 7SJ61 Technical Data Manual

2

Supported Modbus functions

Supported Modbus functions
Function Function
code name
1 Read Coil
Status
(0x-Register)
2 Read Input
Status
(1X-Register)
3 Read Holding
Registers
(4X-Register)
4 Read Input
Registers
(3X-Register)
5 Force Single
Coil
(0x-Register)
6 Preset Single
Register
(4X-Register)
7 Read
Exception
Status
8 Diagnostics
1
Broadcast messages from Modbus master to the Modbus slaves using slave address 0 in the modbus message
(ref. to paragraph "Processing of broadcast messages" in chap. 1).
7SJ61/62/63 6MD63 - Modbus
C53000-L1840-C001-01
The following Modbus functions are supported by the Modbus slave of
the SIPROTEC device:
Reading one or several coil status registers of the Modbus slave.
A maximum of 1970 registers can be read with one message.
The coil status registers reflect the ON/OFF status of discrete outputs
of the SIPROTEC device.
Reading one or several input status registers of the Modbus slave.
A maximum of 1970 registers can be read with one message.
The input status registers reflect the ON/OFF status of discrete inputs
and the status of the protection function of the SIPROTEC device.
Reading one or several holding registers of the Modbus slave.
A maximum of 125 registers can be read with one message.
The holding registers contain device status annunciations, measured
values – mean values and metered measurands.
Reading one or several input registers of the Modbus slave.
A maximum of 125 registers can be read with one message.
The input registers contain recorded measured values.
Writing (force to ON or OFF) one coil status register (and binary output
of the SIPROTEC device assigned with that).
Use function code 15 to force multiple coil status registers.
Function presets a value into a single holding register.
Use function code 16 to preset multiple holding registers.
There are none writable holding registers for the SIPROTEC devices at
present.
This function responses the value of the eight exception status coils to
the Modbus master.
The Modbus slave of the SIPROTEC device uses coil status register
257..264 as exception coils.
This function provides diagnostic values to the Modbus master.
Subfunctions 0 and 2 are implemented.
•
Funktion 0:
The data passed in the query data field of the message to the
slave is to be returned (looped-back) in the response.
•
Funktion 2:
The contents of the diagnostic register is returned in the response
to the master. For this the contents of the holding register 129 is
used.
Description
2
Broadcast
1
supported?
no
no
no
no
yes
yes
no
no
2-1