Behind our simplified name “Siemens TCP” is the RFC1006 protocol with the complex name “ISO Transport Service on top of the TCP”. It is used to connect Siemens S7-300, Siemens S7-400, Siemens S7-1200 or Siemens S7-1500 controllers. With the cloud adapter, a Siemens PLC can be connected to a powerful cloud solution without MindSphere.
For the cloud connection, the software module Universal Cloud Adapter is required. The Cloud Adapter can be installed on any Windows or Linux device (x86, x64 or ARM). The setup is explained in “Getting Started“. Alternatively, you can also use the AnyViz IoT Gateway.
The protocol based on TCP/IP requires one connection per device or per communication processor. SIMATIC® S7 devices support the protocol in passive mode, i.e. they work as servers and accept client connections.
FunctionalityIn addition to the IP address, information about the communication processor must be specified in the form of rack and slot. A connection must therefore be created in the cloud adapter for each Siemens controller. Since a browse function is not available in the protocol, the variables to be exchanged are parameterized in a list. By specifying the data block and address, individual values can be read and written. Different memory areas of the S7 automation devices can be accessed. The Universal Cloud Adapter supports access to data blocks, input registers and output registers.
After creating the connection and adding variables, the communication status is immediately visible in the interface of the cloud adapter. The values of all variables are displayed live. This enables immediate validation of the entries made.
In newer controllers, the communication protocol must first be activated via the “PUT/GET” function in the configuration. In addition, the optimized block access may have to be deactivated. This is described in detail in the Cloud Adapter documentation.
Because Siemens controllers are very widespread, the connection to PLCs is necessary. In this case, coupling via RFC1006 is a convenient solution. With the introduction of TIA-Portal®, however, a new communication standard was created that can no longer be used by third-party providers. Therefore it is recommended to use the OPC-UA standard for new projects.
