In all likelihood, your automation applications forge ahead thanks to Modbus. It is also safe to say that this widely used industrial communications protocol, following a master-slave architecture, will remain the lifeblood of networks for a long time to come. Its two prominent formats—Modbus RTU and Modbus TCP (a modified version of the former)—work their magic in serial-based communications and Ethernet-based connections, respectively.
A number of reasons justify Modbus’s status as the de facto industrial communications protocol. Modbus RTU, specifically, is easy to install in field devices. Furthermore, it allows for easy troubleshooting that is not too costly. Modbus RTU’s cousin, Modbus TCP, is for the same reasons the marrow in Ethernet connections. The snag is that they have communications issues, and therefore need a mediator to smooth things out between them. So, network engineers are constantly scrambling for the right solution to ensure that all the serial devices can communicate with the SCADA host. This has become a pertinent issue as more and more serial devices are connecting to Ethernet networks.
Along with this issue of incompatibility, other challenges also come with the territory. The first challenge involves the vast array of proprietary SCADA software on the market. As each software program brings different supporting abilities for Modbus drivers, things become complicated for system operators to match the right product with their network’s requirements. Throwing them further off balance are continuous requests by multiple SCADA hosts to access the same Modbus RTU-supported device. In addition to all the foregoing, operators must also ensure a faster response time of devices in mission-critical applications.
In this article we will suggest solutions to these challenges. Most of the solutions involve embedding gateways in your network to make sure you get the most out of your serial devices.
The Link That Makes Things Tick
Right now, the marketplace is crowded with SCADA software offering different capabilities to support Modbus drivers. Therefore, you need to know beforehand exactly which SCADA software will be the perfect match for your system. In this section, we will briefly look at a few common scenarios.