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Siemens FetchWrite

Fetch/Write is a TCP/IP-based communication protocol that facilitates crucial data exchange between PLC and associated systems including SCADA, HMI devices, and other PLCs. In this setup, the 'Fetch' operation retrieves data from the PLC, while the 'Write' operation allows for data input into the PLC, ensuring a seamless data flow for optimized automation processes.

Neuron Siemens FetchWrite plugin is used for accessing Siemens PLCs with network expansion module CP443, such as s7-300/400.

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 FetchWrite plugin.

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 AddressRemote plc ip
PLC PortRsemote plc port, default 102

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
  • INT64
  • UINT64
  • BIT

Address Format



DBint16, uint16, bit, int32, uint32, int64, uint64, float, double, stringreadData block in main memeory, word
Mint8, uint8, int16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writeFlag area, byte
Iint8, uint8, int16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writePII-process image of the inputs, byte
Qint8, uint8, int16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writePIQ-process image of the outputs, byte
PEPAint8, uint8, int16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writeIO modules, byte
Zint16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writeCount cells, word
Tint16, uint16, bit, int32, uint32, int64, uint64, float, double, stringread/writeTime cells, word


Optional, refers to a certain digit of a certain address.


When the data type is a string type, it is a required item, indicating the length of the string.

Example Addresses

AddressData TypeDescription
I0int16I area, address 0
I1uint16I area, address 1
Q2int16Q area, address 2
Q3uint16Q area, address 3
PEPA4int16PEPA area, address 4
PEPA5int16PEPA area, address 5
T6int16T area, address 6
T7int16T area, address 7
Z8uint16Z area, address 8
Z9uint16Z area, address 9
DB10.DBW10int16DB area, address 10, start 10
DB12.DBW10uint16DB area, address 12, start 10
DB10.DBW10floatDB area, address 10, start 10
DB11.DBW10doubleDB area, address 11, start 10
I0.0bitI area, address 0, No. 0 bit
I0.1bitI area, address 0, No, 1 bit
Q1.0bitQ area, address 1, No. 0 bit
Q1.2bitQ area, address 1, No. 2 bit
PEPA2.1bitPEPA area, address 2, No. 1 bit
PEPA2.2bitPEPA area, address 2, No. 2 bit
T3.3bitT area, address 3, No. 3 bit
T3.4bitT area, address 3, No. 4 bit
Z4.5bitZ area, address 4, No. 5 bit
Z4.6bitZ area, address 4, No. 6 bit
DB1.DBW10.1bitDB area, address 1, start 10, No. 1 bit
DB2.DBW1.15bitDB area, address 2, start 10, No. 1 bit
DB1.DBW12.20stringDB area, address 1, start 12, string length 20

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.