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Siemens MPI

MPI is a communication protocol based on the Siemens MPI interface, which allows a PLC to exchange data with other devices (e.g. SCADA systems, HMI devices, other PLCs, etc.) The MPI interface is typically built into S7300 and S7400 PLCs.

The MPI interface is typically built into S7300 and S7400 PLCs. MPI requires a special cable to be accessed by the PC. The MPI needs to be converted to RS232 serial protocol using a 6ES7-972-0CA23-0XA0 module (or a compatible module), and then connected to the PC using a USB-RS232 module, or if the PC has an RS232 interface the second conversion step is not required.

Neuron's MPI plug-in is available for data access on S7300 and S7400 PLCs.

Add Device

In Configuration -> Southbound Devices, click Add Device to create the device node, enter the plug-in name, and select Siemens MPI for the plug-in type to enable the plug-in.

Device Configuration

Click on the Plugin card or Plugin column to go to the Device Configuration page. Configure the parameters required for Neuron to establish a connection with the device, the table below shows the plugin related configuration items.

Connection TimeoutConnection timeout(ms)
Send IntervalSend reading instruction interval(ms)
Target StationTarget station, Default is 2
Serial DeviceSerial device path, Default is /dev/ttyUSB0
Stop BitsStop bits, Default and only 1
ParityParity, Default and only Odd
Baud RateBaud Rate, Default and only 38400
Data BitsData Bits, Default and only 8

Configure Data Groups and Tags

After completing the plugin addition and configuration, to establish communication between the device and Neuron, first add groups and points for the southbound driver.

After completing the device configuration, on the Southbound Devices page, click on the Device Card/Device column to go to the Group List page. Click Create to create the group, set the group name and acquisition interval. After completing the creation of the group, click the group name to enter the Tag List page to add the device points to be collected, including point address, point attributes, data type, etc.

For the public configuration item section, you can refer to Connecting Southbound Devices, this page will introduce the supported data type and address format section.

Data types

  • INT8
  • UINT8
  • INT16
  • UINT16
  • INT32
  • UINT32
  • INT64
  • UINT64
  • BIT

Address format



AreaData TypeAttributeDiscription
DB.DBBint8,uint8,int16,uint16,bit,int32,uint32,int64,uint64,float,double,stringRead/WriteMain memory data block, read/write bytes
Mint8,uint8,int16,uint16,bit,int32,uint32,int64,uint64,float,double,stringRead/WriteMemory block, read/write bytes


Optional, refers to a bit of an address, range 0~7.


Required when the data type is string, indicating the length of the string.

Example Addresses

AddressData TypeDescription
DB1.DBB10int16DB1 Area,Starting data address is 10
DB2.DBB10uint16DB2 Area,Starting data address is 10
DB1.DBB12floatDB1 Area,Starting data address is 12
DB1.DBB14doubleDB1 Area,Starting data address is 14
DB1.DBB19.1bitDB1 Area,Starting data address is 19,2nd bit
DB1.DBB19.7bitDB1 Area,Starting data address is 19,8th bit
DB1.DBB20.20stringDB1 Area,Starting data address is 20,string length is 20
M98int8M Area,Starting data address is 98
M99uint8M Area,Starting data address is 99
M100int16M Area,Starting data address is 100
M102uint16M Area,Starting data address is 102
M104floatM Area,Starting data address is 104
M106doubleM Area,Starting data address is 106
M111.3bitM Area,Starting data address is 111,4th bit
M112.20stringM Area,Starting data address is 20,string length is 20
I2.1bitI Area,Starting data address is 2,1st bit
Q0.7bitQ Area,Starting data address is 0,7th bit

Data Monitoring

After completing the point configuration, you can click Monitoring -> Data Monitoring to view device information and control devices. For details, refer to Data Monitoring.