May 2023 Volume 5

AUTOMATION

something goes awry, and that work is usually supported by the OEM. So, focusing on code development as is so often done in training classes does not truly suit the needs of plant operations to maintain operation or interface with Industry 4.0 development. Of course, a basic understanding of code logic (often-times ladder logic) is required to add interface signals and production data with other plant data management systems. An in-depth knowledge of coding is usually provided by the OEM machine programmer as opposed to an operations engineer. When transitioning plant technologists from training to daily operation or Industry 4.0 implementation, attending carefully to a fewkey steps in the automationmanagement process can lead to successful outcomes. The key process points that must be developed by plant operation teams should include: 1. Knowledge and documentation of which software package and which software version are required for each machine in the factory. (Rockwell: RSLogix 5, RSLogix 500, RSLogix5000 (version critical), Studio5000/Siemens: Step 7 Classic, TIA Portal) 2. Knowledge and documentation of what communication schemes are required for connection to the PLC, HMI, and frequency drives. (Rockwell: DH+, RS485, EthernetIP/ Siemens: Profibus, Profinet, MPI) 3. Keep a functioning and well tracked supply of connection cables for each piece of equipment. Ideally, there should be a connection cable for each machine stored near the PLC or other equipment using a visual factory type implementation. (Rockwell: Null Modem, Serial, DIN, Ethernet Crossover/ Siemens: MPI, ProfiNet). 4. Maintain, backup, and update a set of laptops with the proper software to connect, troubleshoot and change PLC and HMI programs. 5. Obtain, maintain, and perform regular backups of all equipment PLC, HMI, frequency drive, and servo drive programs/parameters. Keep a history in a safe file location for the possibility of corruption of existing files through human or non-human interaction. 6. Create a process sheet for each piece of equipment detailing how to connect to the PLC, HMI, drives, etc. These sheets should be simple to follow and filled with screenshots and documentation of all connection settings. Routine execution of connection and backup keeps knowledge fresh. I find that managing these tasks is presenting challenges to many plant operations professionals. This high-tech knowledge causes some anxiety among plant technicians who spend most of their time focused on plant-wide production issues and not automation connectivity processes. The documentation of connecting to and maintaining the technology that powers the automation in a plant is the key to being free from being reliant on one/few people and/or outside contractors to execute this work. Plant engineers and technology people in the plant know the critical details of an operation much better than most outside contractors. The work of

bringing an automated factory into an Industry 4.0 environment is best handled with those who live and breathe the operation. Top notch documentation specific to each piece of equipment and easy access to the required cables, hardware and software takes the hesitation out of the necessary step of connecting to PLC equipment and bringing the factory into a smart manufacturing environment. In a robust Industry 4.0 environment, Ethernet connectivity is the clear choice to communicate with automated machinery. A serious plunge into smart manufacturing requires a good strategy to make communication and connections with older and new equipment. Many older PLCs can be connected by a gateway to translate older communication bus systems like DH+, Modbus, ControlNet, DeviceNet, and Profibus to an Ethernet platform. Some older equipment is already outfitted with Ethernet connectivity. New equipment is usually ready for Ethernet connectivity, but it is highly recommended to use a gateway to connect each device to the plant network. It is important to choose the correct gateway for this endeavor. This brings us to the interface between IT and Automation. IT departments (and rightfully so) are ever mindful of security. Connecting machines all around the plant not only poses security risks to the equipment from outside threats, but also increases traffic on the existing LANs. The security from outside threats can be managed by intelligent selection of secure gateway platforms. These so-called M2M (machine to machine) gateways can provide secure connections to plant PLCnetworks. Management of ever-increasing network traffic requires any plant network ready for 4.0 to consider an architecture with enough routing and switching that canmanage the increased demand for communication. This is certainly a topic unto itself. Though not a thorough treatment, I would like to touch on some quick considerations from the automation technology side for managing network traffic when connecting the equipment to a plant network. Most new automation systems have their own LANs and would need to be connected to a plant by a gateway or router. In this case the plant IT department can work with the automation specialist to choose the best method of connection. In some instances, it may be tempting to connect PLC directly to the plant network. Here, it is important to consider the CIP Class of the devices involved. CIP Class 1 connections are typically going to produce more network traffic due to the fact that information is communicated cyclically. Class 3 connections should be used when possible as they are request/demand based and more efficient in terms of broadcast bandwidth. Unfortunately, some older PLCs cannot support Class 3 CIP connections and Class 1 connection would be unavoidable without a gateway. Adding numerous pieces of equipment to a plant network takes careful attention and understanding of the ways to keep communication efficient. The task of minimizing network traffic must be jointly considered with plant IT and automation specialists as the proper selection of gateways is important. The principles of documentation and process management still apply to this interface between plant technology and IT departments and must be given due consideration.

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