Communicating with S7-300 or S7-400

Introduction

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

Connection using an MPI adapter,
Connection using an Ethernet Module.

Connection Using an MPI Adapter

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

PC connected to two S7-300 PLCs via an MPI adapter

These MPI adapters are supported:

HMI Adapter 6ES7 972-0CA11-0XA0
PC Adapter 6ES7 972-0CA23-0XA0, 6ES7 972-0CA22-0XA0, 6ES7 972-0CA21-0XA0
TS Adapter 6ES7 972-0CA34-0XA0, 6ES7 972-0CA33-0XA0, 6ES7 972-0CA32-0XA0

Connection Cables

To connect the MPI adapter to a D-Subminiature 9 pin serial port, typically found on a Personal Computer (PC), a null-modem connection cable with this wiring is required:

MPI Adapter		PC
RXD	2	3	TXD
TXD	3	2	RXD
DTR	4	6	DSR
GND	5	5	GND
DSR	6	4	DTR
RTS	7	8	CTS
CTS	8	7	RTS

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

Fernhill SCADA Configuration

Configure one Siemens S7 MPI Channel Tag. Configure one Siemens S7 Serial PLC Tag for each PLC on the MPI bus.
The Siemens MPI adapter supports two RS-232 communication speeds: 19200 and 38400 Baud. To work with Fernhill SCADA the Mode settings of the Siemens S7 MPI Channel Tag should match the RS-232 communications setting of the MPI Adapter.

RS-232 Speed Channel Mode

19200 Baud=19200 Parity=O Data=8 Stop=2

38400 Baud=38400 Parity=O Data=8 Stop=2
When powered up, HMI and PC adapters require configuration to join the MPI bus. The Fernhill SCADA Siemens S7 driver automatically configures HMI and PC adapters using the settings from the Siemens S7 MPI Channel Tag.
TS adapters are configured offline using the Siemens Teleservice configuration tool. TS adapters retain their settings between power cycles. The Fernhill SCADA Siemens S7 driver does not configure TS adapters.

RS-232 Speed	Channel Mode
19200	Baud=19200 Parity=O Data=8 Stop=2
38400	Baud=38400 Parity=O Data=8 Stop=2

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 Setup 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 PLCs.

Siemens S7-300/400 Ethernet Setup 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 PLCs and automatically create tags for any PLCs found.

Siemens S7 Driver

For information on the Siemens S7 Driver.

Fernhill SCADA Drivers

For information about other drivers available in Fernhill SCADA.

Glossary

For definitions of the terms used in Fernhill SCADA.