Integrating Serial Devices into the Industrial Internet of Things

The Industrial Internet of Things (IIoT) is not at all about breaking with the past. Instead, the focus is on a more intelligent use of existing assets to tap into the potential of the IIoT. Factors such as devices’ longevity, the simplicity of serial-to-Ethernet communication, and cost considerations are driving the serial-to-Ethernet phenomenon in the IIoT.

Issues of Connecting RS-232/422/485 Devices to the IIoT
To connect legacy serial devices to an Ethernet-based network, a serial-to-Ethernet converter, or so-called serial device server, can be installed. Several factors need to be considered when serial device servers are used to support IIoT cloud applications. For example, multiple polling applications are very common in the IIoT. A SCADA system and a remote cloud application may issue a command simultaneously to a serial device via the serial device server. In addition, most serial devices use proprietary protocols, so you need to find solutions to convert serial data into Ethernet packets. Furthermore, as a large number of serial devices are connected to the same network in most IIoT applications, these connections will require many resources in a control room or cloud application.

NPort’s Operation Modes Simplify Serial Device Communications
Moxa’s NPort serial device servers support a command-by-command function for IIoT multiple polling applications on a first in, first out (FIFO) basis. Only the first query will be sent to a serial device, and the rest will have to wait in the FIFO queue. Without a FIFO design, an extra IoT gateway that supports multiple polling is required. The NPort series also has a serial tunneling function to handle standard (Modbus/DNP3) and proprietary protocols of legacy equipment. In addition, more connections require more bandwidth. However, Moxa’s NPort serial device servers have a smart connection handling function that automatically connects or disconnects a TCP connection when a transmission is completed. The NPort closes the connection to save bandwidth.