Mb_Server (Communicate Using Profinet As Modbus Tcp Server) - Siemens SIMATIC S7-1200 System Manual

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MB_SERVER (Communicate using PROFINET as Modbus TCP server)

The "MB_SERVER" instruction communicates as Modbus TCP server through the

PROFINET connector on the S7-1200 CPU. The "MB_SERVER" instruction processes

connection requests of a Modbus TCP client, receives and processes Modbus requests, and

sends responses.

To use the instruction, you do not require an additional hardware module.

Security information

Note that each client of the network is given read and write access to the process image

inputs and outputs and to the data block or bit memory area defined by the Modbus holding

The option is available to restrict access to an IP address to prevent unauthorized read and

write operations. Note, however, that the shared address can also be used for unauthorized

Table 13- 135 MB_SERVER instruction

S7-1200 Programmable controller

System Manual, V4.2, 09/2016, A5E02486680-AK

"MB_SERVER_DB"(

DISCONNECT:=_bool_in_,

CONNECT_ID:=_uint_in_,

IP_PORT:=_uint_in_,

NDR=>_bool_out_,

DR=>_bool_out_,

ERROR=>_bool_out_,

STATUS=>_word_out_,

MB_HOLD_REG:=_variant_inout_);

Communication processor and Modbus TCP

13.8 Legacy Modbus TCP communication

MB_SERVER communicates as a Mod-

bus TCP server through the PROFINET

connector on the S7-1200 CPU. No

additional communication hardware

module is required.

MB_SERVER can accept a request to

connect with Modbus TCP client, receive

a Modbus function request, and send a

response message.