Technology limitations: Real-time ability and safetyMost vPLC vendors do not guarantee the hard real-time performance ability of their vPLCs. It depends heavily on the infrastructure, vPLC physical hosting, and software architecture on the host device. Hosting in the cloud can barely manage short cycles. Achieving responsiveness and connectivity on non-PLC hardware comparable to that of dedicated PLC hardware is difficult, even with on-premises hosting.The operational safety of vPLC is not provided by the vendors, except CODESYS, which certified its safety product.
Infrastructure and resources on the user side need to be preparedThe performance of vPLC depends largely on the customer‘s infrastructure and networks. A converged, well-managed network is a prerequisite. Infrastructure on the customer side should not only comply with the requirements of the vPLC vendor but also provide for the application redundancy and flawless performance of the hosting server or device. OT-grade security of the devices, servers, and software is another critical point for soft PLC deployments. Legacy infrastructure and systems are barriers to vPLC implementation.
Responsibility for the PLC’s performance between the vendor and customer is still to be definedWith the complete decoupling of the hardware and software, responsibility for the PLC’s performance will be shared between vendor and customer. Depending on the business model, more resources can be required from customers compared to the conventional or soft PLC setup. Together, these barriers increase the total cost of ownership, and additional investments are needed.
Standards must be definedStandards for the vPLC’s performance, reliability, interfaces, and interoperability are not developed.
Collaboration between OT and IT neededThe management and engineering of vPLCs cannot be fully in the hands of IT—OT is the user and has the needed expertise for the OT applications. Close collaboration and skilled personnel with knowledge of industrial PLC and IT for installation, management, and security of vPLC and underlying system should be available on customer side.
The service and application ecosystem must be developedAlmost all currently presented vPLCs work within vendor’s ecosystems and edge/cloud platforms. This makes hardware-independent vPLCs dependent on the vendor’s software. The functionality of a vPLC outside of the vendor’s system is not guaranteed. To make vPLC vendor-independent, the service ecosystem for vPLC management and maintenance needs to be developed and partnerships need to be formed.