Siemens S7-1200/1500 Ethernet Connection Guide

Help Contents


The Siemens S7-1200/1500 PLCs all support integrated Ethernet communications. Software programs such as Fernhill SCADA can monitor and control S7-1200/1500 PLCs using the built-in Ethernet port.

Communication Overview

A typical communication scenario is shown in this diagram:

Diagram showing a Siemens S7-1200 PLC connected to a PC running Fernhill SCADA

To establish communications between Fernhill SCADA and a Siemens S7-1200/1500 PLC you need to:

Setting up a Siemens S7-1200/1500 PLC

Accessing Data Blocks (DB)

The S7-1200 and S7-1500 PLCs introduce the concept of an Optimized Data Block. An Optimized Data Block does not have a fixed defined structure; the elements within the block are managed by the system. An Optimized Data Block can not be accessed by the S7 Protocol. To access data blocks from Fernhill SCADA, you should use global data blocks configured for standard access.

Optimized Block Access is turned on by default. To configure the data block for standard access, open the data block properties and clear Optimized block access:

Data block properties with optimized block access field highlighted

Configuring Access Protection

Fernhill SCADA uses GET and PUT commands to read from and write to Siemens S7 PLCs. For Siemens S7-1200 PLCs with firmware version 4.0 or later, and S7-1500 PLCs, access to GET and PUT commands is turned off by default. You should enable PUT/GET commands in the Protection settings page of the PLC:

PLC Properties showing the option to enable PUT/GET commands

Configuring Fernhill SCADA

There are two options for configuring Ethernet communications from Fernhill SCADA to a Siemens S7 PLC Tag:

Further Information

Siemens S7 TCP Autodetect Wizard

For how to automatically configure Fernhill SCADA to communicate with Siemens S7 PLCs using Ethernet.

Siemens S7 Ethernet channel

For information about Siemens S7 Ethernet channel tag.

Siemens S7 TCP/IP PLC

For information about Siemens S7 TCP/IP PLC tag.

Siemens S7 Driver

For information about the Siemens S7 Driver.


For the meaning of terms used in Fernhill SCADA.