Dial-up remote access
Teleservice
Internet remote access
Remote machine diagnosis
Predictive Maintenance
Alarm notification system
SCADA applications
Remote metering
Industrial extranets
Gateway for ASCII devices
SNMP management
Talk2M
Talk2M is a new, smart, Web-based remote access method. Talk2M gives you single-click Internet access to your remote machines with PLC and remote sites worldwide.
Learn more
Many devices such as scales, electricity meters, pH meters, and even some displays are limited to a simple ASCII protocol on RS232 for their communication tasks. These devices can be interfaced to Ethernet by using VCOM solutions (also called device servers), which extend the RS232 link via an Ethernet LAN to the COM port of a PC. Although this works, it is prone to timeout problems, and it is difficult to interface to applications that do not run on the PC where the serial link terminates. Fortunately, eWON technology changes this situation.
eWON technology provides an Ethernet interface with several advanced services for serial ASCII devices, so that they can be accessed directly from PLCs, SCADA devices, MES systems, and other high-end applications.
In this scenario, the eWON serial port is connected to a measuring device. A Basic script controls the serial port, sending ASCII characters as commands and reading the responses from the device in the form of formatted ASCII strings or as otherwise required by a proprietary protocol. The script extracts the relevant data from the ASCII strings and stores it in eWON memory tags. Once the data is present in eWON memory, it is available for publishing using Modbus TCP, SNMP, or on web pages. eWON units can also forward data to PLC variables for use in other processes.
With eWON technology, a serial device that was initially dedicated to local use with its own proprietary PC application and operator interface or VCOM channel is now available from anywhere on the LAN and can be used by several applications at the same time. It can be controlled via web pages and monitored from the network, and the data is available for logging or process control. eWON technology even provides alarm management capabilities.
The simplicity and robustness of this solution are its main advantages. It is cost effective and supports the protocols of most major PLC manufacturer.
All that is necessary is to implement the proprietary protocol of the device. For this purpose, eWON units provide events and dedicated Basic keywords that enable them to interface rapidly to any protocol.
In this scenario, the eWON unit also interfaces a serial device through its Basic scripting ability and sends dedicated ASCII characters over an RS232 link for control purposes. Additionally, it provides Internet services (HTTP for web pages and FTP for data transfer) for controlling the device from anywhere on an intranet.
Carrying out serial communication over Ethernet (such as with VCOM) works well if the network conditions are favorable (data transfer speed, response delay, etc.) and as long as the scenario is simple.
However, in many cases the PC application and the serial device cannot tolerate significant delays in the communication process because they are designed to be linked directly linked to each other. Transmission retries and timeouts can easily occur if the network speed is not high enough. Ultimately, the PC application may conclude that it has lost the connection with the device. By using a more robust communication protocol designed for network and Internet connectivity, namely IP and IP-based services, eWON connectivity is much more stable and reliable even on busy networks or over slower lines.
eWON technology offers standard IT services (web pages and FTP data transfer), making things easier to access and interface from a PC.
The eWON 500 (reference EW05201) is used in all the examples described in this application note. In many cases it is the most suitable model.
eWON technology bridges the gap between a standard PC or a PLC on an industrial network and serial devices, not only from a pure hardware perspective but also at the application level. This makes eWON technology an efficient and unique solution that is already commercially available.
eWON technology provides an Ethernet interface with several advanced services for serial ASCII devices, so that they can be accessed directly from PLCs, SCADA devices, MES systems, and other high-end applications.
Example 1: Reading data from a measuring device and publishing it on Ethernet
In this scenario, the eWON serial port is connected to a measuring device. A Basic script controls the serial port, sending ASCII characters as commands and reading the responses from the device in the form of formatted ASCII strings or as otherwise required by a proprietary protocol. The script extracts the relevant data from the ASCII strings and stores it in eWON memory tags. Once the data is present in eWON memory, it is available for publishing using Modbus TCP, SNMP, or on web pages. eWON units can also forward data to PLC variables for use in other processes.
Advantages
With eWON technology, a serial device that was initially dedicated to local use with its own proprietary PC application and operator interface or VCOM channel is now available from anywhere on the LAN and can be used by several applications at the same time. It can be controlled via web pages and monitored from the network, and the data is available for logging or process control. eWON technology even provides alarm management capabilities.
The simplicity and robustness of this solution are its main advantages. It is cost effective and supports the protocols of most major PLC manufacturer.
All that is necessary is to implement the proprietary protocol of the device. For this purpose, eWON units provide events and dedicated Basic keywords that enable them to interface rapidly to any protocol.
Example 2: Controlling a serial device from Ethernet
In this scenario, the eWON unit also interfaces a serial device through its Basic scripting ability and sends dedicated ASCII characters over an RS232 link for control purposes. Additionally, it provides Internet services (HTTP for web pages and FTP for data transfer) for controlling the device from anywhere on an intranet.
Advantages
Carrying out serial communication over Ethernet (such as with VCOM) works well if the network conditions are favorable (data transfer speed, response delay, etc.) and as long as the scenario is simple.
However, in many cases the PC application and the serial device cannot tolerate significant delays in the communication process because they are designed to be linked directly linked to each other. Transmission retries and timeouts can easily occur if the network speed is not high enough. Ultimately, the PC application may conclude that it has lost the connection with the device. By using a more robust communication protocol designed for network and Internet connectivity, namely IP and IP-based services, eWON connectivity is much more stable and reliable even on busy networks or over slower lines.
eWON technology offers standard IT services (web pages and FTP data transfer), making things easier to access and interface from a PC.
Featured products
The eWON 500 (reference EW05201) is used in all the examples described in this application note. In many cases it is the most suitable model.
Conclusion
eWON technology bridges the gap between a standard PC or a PLC on an industrial network and serial devices, not only from a pure hardware perspective but also at the application level. This makes eWON technology an efficient and unique solution that is already commercially available.
