The Project

Trains are usually washed on entry to a depot.  Wash plans are usually situated around half a mile away from the main depot.  Due to these remote locations, wash plants are normally controlled automatically by trains and track switches, or from the main depot.

In most cases, wired data connections to wash plants are not available, so our solutions use a 3G router and sim card.  The sim card used in the 3G router is an industrial M2M (machine to machine) implementation, with a fixed IP to ensure remote access is available at all times.  The router itself uses port forwarding setup to allow communications with both PC and PLC. 

Internally a NAT network is created, with the router, PC and PLC all maintaining fixed IP addresses.  Specific ports are forwarded to these addresses allowing direct PLC access from off-site, and remote control of the PLC.

Standard ethernet is used across the internal network, connecting the Siemens S7300 series PLC and an industrial touchscreen PC running Windows XP Embedded.  This PC contains both the SCADA (Supervisory Control and Data Acquisition) system - built using GE Fanuc iFix 3.5, and the Access database for logging.

The PLC becomes an available 'node' within standard Siemens software once the remote access is launched.  This allows PLC engineers to connect and make changes to the software without the need for a costly site visit.  The PC can also be accessed remotely over RDP (Remote Desktop Protocol).  This means a remote user can take advantage of the SCADA system to change or monitor variables.

Finally the web based application is also accessible from any PC with internet access allowing plant operatives to access logs and run reports on saved information.