Machine builders and plant integrators have a growing need for remote maintenance of their equipment and installations in order to remotely remedy problems in a large installed base or provide their customers with better service. The eWON industrial router is the most flexible solution for remote maintenance applications. Serial and Ethernet-based PLCs can be maintained remotely using the PLC software, allowing automation engineers to spend less time on customer sites and reduce expensive travel costs.

Architecture 1: Dial-up remote maintenance of PLCs

The eWON 2101CD industrial router supports links between PLC programming software running on a PC (Siemens Step7®, Rockwell RS Logix®, or Schneider PL7 Pro® and Unity®) and a matching PLC (Siemens S7® series, Rockwell Logix® family, or Schneider Modicon® or Telemecanique®) located remotely, using a PPP connection with an embedded PSTN, ISDN or GSM data modem.   

Once the dial-up connection is established, the programming software accesses the PLC transparently. Remote access to the PLC is provided by connecting to the PLC using one of the following options: 

• the PLC’s Ethernet port (if available) from the eWON Ethernet port;  
  
• the PLC’s programming port from the eWON serial port.  
  

With the first option, the eWON unit acts as a pure IP router, while with the second option it also acts as a router with a transparent Ethernet-to-serial gateway. This gateway is where the translation between the Ethernet protocol to the serial protocol occurs, such as: 

• Modbus TCP to Modbus RTU;
• XIP to Uni-Telway;
• EtherNet/IP to DF1;
• FINS TCP to FINS Hostlink;
• ISO TCP to PPI, MPI or Profibus;
• VCOM to ASCII.

This provides seamless interoperability with the PLC products of leading manufacturers. 

With remote maintenance services, it may be desirable for the recipient to bear the cost of the dial-up connection instead of the provider. In the past, the connection was established by a call from the technician to the remote device, which meant it was an incoming PPP connection. With eWON callback function, the connection is established from the remote device to the service provider, which means it is an outgoing connection. This enables machine builders to have their customers bear the cost of remote maintenance connections. For this reason, the eWON unit has an integrated automatic callback function that can be triggered by: 

• a predefined number of ring tones;
• a button click to activate call-back.

The second option requires the user to first log in to the eWON unit, which means that callback operations are only available to previously authenticated users. 

Advantages

The eWON 2101CD industrial router provides an Ethernet port as well as a serial port, which allows remote operation activities to be performed at two levels: 

• Ethernet devices;
• serially connected devices.

For machine builders or OEM customers, this also means that a single model can support two different types of equipment, and that equipment that is presently served over a serial interface can be served over Ethernet in the future by the same eWON model.  

For PLCs with serial interfaces, the transparent gateway capability of the eWON unit eliminates the need for additional software, such as is used in competing remote maintenance and teleservice solutions. This reduces the total cost of ownership (TCO) while providing the same connectivity as direct connection of the PLC to the programming port. The eWON 2101CD industrial router solution offers far more than an conventional modem solution. Thanks to the IP router functionality, PLC remote maintenance ensures: 

• high reliability level of the telecom connection;
• optimized data transfer rate.

Featured products

The eWON 2101CD industrial VPN router range has the following modem options:

• ISDN: eWON ref. EW332x3. This is the first choice, with a guaranteed bandwidth of 64 kbit/s. In practice, it cannot be widely used because it is difficult to install (special equipment is required) and it is available only in Europe.  
  
• PSTN: eWON ref. EW332x4. This is the second choice. Although it is available worldwide, the bandwidth is unfortunately not guaranteed and is highly dependent on the line quality.
  
• GSM data: eWON ref. EW332x8. It cannot be recommended for this application because experience shows that it is too slow (9.6 kbit/s).  
  

The ‘x’ in the reference number stands for:   

• ‘6’ if the MPI/Profibus protocol must be used for connection to the PLC(s) 
• ‘0’ otherwise.

   

Architecture 2: Internet / Talk2M remote PLC maintenance

Talk2M is a new, smart Web-based remote access method for use over mobile Internet (GPRS, EDGE, UMTS, or HSUPA/HSDPA) or broadband Internet (via a LAN). With its transparent gateway and IP router features, the eWON unit in combination with Talk2M facilitates the remote maintenance of major PLC brands using an Ethernet port or a serial port.

Advantages

Talk2M eliminates the difficulties associated with implementing worldwide Web-based remote access solutions involving many different technologies and media.

The eWON industrial router with an embedded GPRS, EDGE, UMTS or HSDPA/HSUPA modem can be remotely activated by sending a text message. After the eWON unit receives the text message, it automatically connects to the Talk2M server. This means that the user does not have to maintain a permanent GPRS, EDGE, UMTS or HSDPA/HSUPA connection from the eWON site to the Talk2M Web server. The Talk2M solution with a GPRS or EDGE connection from the remote sites only needs standard national SIM cards, eliminating the need for a dedicated international APN or dedicated SIM cards.

The most powerful and innovative architecture with Talk2M is obtained by using the existing Ethernet LAN infrastructure at the remote site, with its Internet connection, to make the remote device accessible from anywhere in the world over the Internet. As a result, no additional dedicated telecom media are necessary. 

Featured products

For cellular/mobile connections, the eWON 2101CD industrial router has the following modem options:

• GPRS: eWON ref. EW332x8
• UMTS (3G) (with fallback to EDGE/GPRS): eWON ref. EW332xB
• HSUPA (with fallback to HSDPA, UMTS, EDGE or GPRS): eWON ref. EW332xA

For an Internet connection through the local LAN, eWON 2005CD industrial router has the following options:

• LAN connection: eWON ref. EW262x1
• LAN connection with GPRS/EDGE backup mode: eWON ref. EW262x7
• LAN connection with HSUPA backup (with fallback to HSDPA, UMTS, EDGE or GPRS): eWON ref. EW262xA

For ADSL connection, eWON 2104CD industrial router range has the following modem options

• ADSL modem: eWON ref. EW272x1
• ADSL modem with PSTN backup mode: eWON ref. EW272x4
• ADSL modem with GPRS/EDGE backup mode: eWON ref. EW272x7

The ‘x’ in the reference number stands for:   

• ‘6’ if the MPI/Profibus protocol must be used for connection to the PLC(s) 
• ‘0’ otherwise.

Conclusion

eWON industrial routers give machine manufacturers, OEMs and system integrators a simple and immediate remote maintenance solution. Seamlessly integrated with the PLC programming environment, eWON technology adds remote access capability to automated applications, thereby transforming emergency visits into scheduled maintenance visits. It truly enriches the relationship between service providers and customers.