Communicating with S7-300 or S7-400

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Fernhill SCADA supports these types of connection to Siemens S7-300 and S7-400 PLC Devices:

Connection Using an MPI Adapter

You can connect Fernhill SCADA to S7-300/400 PLC Devices using an MPI adapter:

PC connected to two S7-300 PLC Devices via an MPI adapter

These MPI adapters are supported:

Connection Cables

The MPI adapter can connect directly to a serial port on a Personal Computer (PC). The serial port on a PC is usually a 9 pin D-subminiature connector. This cable is suitable to connect the MPI Adapter to a computer with a 9 pin D-subminiature connector:

As an alternative you can create your own cable using null-modem wiring:

MPI Adapter
DE-9 Female Layout
DE-9 Female Layout

Note: All other pins not shown in the above diagram have no connection.

Fernhill SCADA Configuration

For a detailed walkthrough about manually configuring tags for MPI connection refer to Configuring Tags for Siemens S7 MPI Communication.

Connection Using a CP-343-1 or CP-443-1 Ethernet Module

You can connect Fernhill SCADA to an S7-300/400 PLC using a CP-343-1 or CP-443-1 Ethernet module:

PC connected to an S7-300 PLC via Ethernet

For a detailed overview of setting up an S7-300 or S7-400 Ethernet module refer to Siemens S7-300/400 Ethernet Connection Guide.

If the Ethernet module configured, you can use the Siemens S7 TCP Autodetect Wizard to try and locate the PLC on the network.

Further Information

Configuring Tags for Siemens S7 MPI Communication

For a step by step guide to configuring tags for Siemens S7 MPI connected PLC Devices.

Siemens S7-300/400 Ethernet Connection Guide

For how to configure an S7-300/400 Ethernet module and Fernhill SCADA to work together.

Siemens S7 TCP Autodetect Wizard

For how to search a network for Siemens S7 PLC Devices and automatically create tags for any PLC Devices found.

Siemens S7 Driver

For information on the Siemens S7 Driver.

Fernhill SCADA Drivers

For information about other drivers available in Fernhill SCADA.


For the meaning of terms used in Fernhill SCADA.