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Siemens S7 ISOTCP

Siemens S7 ISOTCP is a protocol developed by Siemens for communication with Siemens S7 series PLCs. This protocol is based on the TCP/IP protocol stack and uses the ISO-TSAP protocol for handling connections and data transmission. It enables read and write operations on various data types of the PLC, including bits, bytes, word, double word, timers, and counters.

The implementation of S7 ISOTCP in Neuron is divided into two plugins.

  • The Siemens S7 ISOTCP plugin is mainly used to connect to PLC modules such as Siemens S200, S200smart, S1200, and S1500.
  • The Siemens S7 ISOTCP for 300/400 plugin is mainly used to connect to PLC modules such as Siemens S300 and S400 that have an Ethernet module.

Add Device

Go to Configuration -> South Devices, then click Add Device to add the driver. Configure the following settings in the popup dialog box.

  • Name: The name of this device node.
  • Plugin: Select the Siemens S7 ISOTCP plugin or Siemens S7 ISOTCP for 300/400.
Siemens S7 ISOTCPFor Siemens S200, S200smart, S1200, S1500 PLC
Siemens S7 ISOTCP for 300/400For Siemens S300, S400 PLC

Device Configuration

After clicking Create, you will be redirected to the Device Configuration page, where we will set up the parameters required for Neuron to establish a connection with the northbound application. You can also click the device configuration icon on the southbound device card to enter the Device Configuration interface.

PLC IP AddressTarget PLC IPv4 Address
PLC PortTarget PLC port, default 102
PDU SizePDU size, default 960
PLC ModuleTarget PLC module, S7-200/300/400/1200/1500
Connection TypeOnly for S7-300/400/1200/1500, Connection type, default PG
CPU RackOnly for S7-300/400/1200/1500, PLC CPU rack, default 0
CPU SlotOnly for S7-300/400/1200/1500, PLC CPU slot, default 1
Local TSAPOnly for S7-200, local TSAP
Remote TSAPOnly for S7-200, remote TSAP


When interfacing with Siemens S7 1200/1500 PLC using the Siemens S7 ISOTCP plugin, certain modifications are required in the Siemens software (TIA16) settings:

  • The optimized block access must be turned off.
  • The access level must be full and the connection mechanism must allow GET/PUT.

For detailed operating steps, please refer to Tailor S7 1200/1500 PLC for Effective ISOTCP Plugin Use.

Configure Data Groups and Tags

After the plug-in is added and configured, the next step is to establish communication between your device and Neuron by adding groups and tags to the Southbound driver.

Once device configuration is completed, navigate to the South Devices page. Click on the device card or device row to access the Group List page. Here, you can create a new group by clicking on Create, then specifying the group name and data collection interval.

Upon successfully creating a group, click on its name to proceed to the Tag List page. This page allows you to add device tags for data collection. You'll need to provide information such as the tag address, attributes, and data type.

For information on general configuration items, see Connect to Southbound Devices. The subsequent section will concentrate on configurations specific to the driver.

Data types

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

Address Format



Iint8/uint8/int16/uint16/bit/int32/uint32/floatreadinputInput I、E
O/Qint8/uint8/int16/uint16/bit/int32/uint32/floatread/writeoutputOutput Q、A
F/Mint8/uint8/int16/uint16/bit/int32/uint32/floatread/writeflagFLAG Memory M
Tint32/uint32/floatread/writetimerTimer T
Cint16/uint16read/writecounterCounter C
DBint8/uint8/int16/uint16/bit/int32/uint32/float/double/stringread/writeglobal DB blockVariable Memory V, DB index 1


For the global data block DB, in the PLC side of the address such as DBX, DBW, DBB, etc., directly converted to DBW can be, do not need to do byte conversion, such as DBX1 -> DBW1.


AddressData TypeDescription
I0int16I area, address is 0
I1uint16I area, address is 1
O2int16O area, address is 2
O3uint16O area, address is 3
Q4uint16Q area, address is 4
F4int16F area, address is 4
F5int16F area, address is 5
M6int16M area, address is 6
T6int32T area, address is 6
T7int32T area, address is 7
C8uint16C area, address is 8
C9uint16C area, address is 8
DB10.DBW10int16In a data block of 10, the starting data word is 10
DB12.DBW10uint16In a data block of 12, the starting data word is 10
DB10.DBW10floatIn a data block of 10, the starting data word is 10
DB11.DBW10doubleIn a data block of 11 , the starting data word is 10


Optional, referring to a bit of an address, range 0 - 7.


When the data type is a string type, it is required and indicates the length of the string.

Example Addresses

AddressData TypeDescription
I0.0bitI area, address 0, bit 0
I0.1bitI area, address 0, bit 1
O1.0bitO area, address 1, bit 0
O1.2bitO area, address 1, bit 2
F2.1bitF area, address 2, bit 1
F2.2bitF area, address 2, bit 2
DB1.DBW10.0bitIn a data block of 1, the starting data word is 10, bit 0
DB2.DBW1.7bitIn a data block of 2, the starting data word is 1, bit 7
DB1.DBW12.20stringIn a data block of 1, the starting data word is 12, string length is 20

Use Case

This chapter also provides practical examples to facilitate a quick start.

Siemens S7-1200 PLC

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.