A popular definition of SCADA is a control system architecture that uses PC's, networked data communications and human machine interfaces for higher level process supervisory management
Manufacturing Automation & SCADA
David Broadbent | Envirotech Molded Products
Let's start with the basics, Supervisory control and data acquisition (SCADA) A popular definition of SCADA is a control system architecture that uses PC's, networked data communications and human machine interfaces for higher level process supervisory management, but uses other peripheral devices such as programmable logic controllers (PLC's), Field I/O devices, industrial machine computer and communication gateways to interface with the plant or machinery. The operator interfaces which enable monitoring and the issuing of process commands, such as controller set point changes, are handled through the SCADA computer system.
Data analytics software used for predictive maintenance, OEE, Production information and other data can also be integrated into the system through an ERP or other Enterprise system. Lets break down some of the terms used and then we will get into some of the specific roles each part plays and the interactions they have with each other.
Human Machine Interface (HMI) The user interface in a manufacturing or process control system. It provides a graphics based panel with controls, feedback, text, buttons and pages of an industrial control and monitoring system. Sometimes referred to as a GUI or Graphical User Interface. These are usually how persons control and interact with the PLC or PC that is controlling the equipment process. Think start/stop, recipes, setup and feedback such as temp's, speeds, positions and other general information. Newer HMI's typically have networking capabilities built into them for centralized control from designated computers on the network.
Field I/O or distributed I/O are controller installations where end devices are located long distances away, systems can greatly reduce wiring costs. Localizing field terminations at the machine or device being monitored/controlled allows for easier installations/modifications & shorter wire runs. A PLC can be used as field I/O but not all field I/O is a PLC, it is basically a unit that controls equipment inputs & outputs that is remotely controlled by you.
An industrial Machine computer is a ruggedized PC that is programmed specifically to operate the equipment it is integrated in. much like a PLC except with specific advantages and disadvantages. for further information i recommend researching the topic further.
Communication gateways are devices that translate a devices particular communication protocol into another communication protocol. They are particularly useful in applications where multiple pieces of equipment from different manufacturers utilize proprietary protocols. Some gateways can translate for multiple devices using different communication protocols like Modbus or RS232 and translate it into say Ethernet/IP. this allows for multiple devices to communicate directly with or through a server or remote PC for cloud computing and data analytics
Taken all together we have the ingredients for SCADA system Architecture. How you configure the SCADA system depends entirely on the specific control and information needs. other variables are the setup and types of equipment controls, HMI's and PLC's for example you have in your system group. I will give a description of a common scenario and how you would use the various components to get the desired result. Say i have a manufacturing plant and it has 3 different machines that i would like to control from a single location with real time information. i would like to gather specific production data for my ERP system. I also want equipment data and sensor information for cloud based analytics resulting in predictive maintenance. first i would need a communication gateway to translate the needed information into a uniform protocol which is then sent over the network. i can then route the data to a control PC for real time information centralized control and remote access of the equipment. Simultaneously i can send the needed data to my server or cloud for integration into my ERP system and data analysis software. This is a very basic example and i suggest you research your needs in depth before any decisions are made. As always if you or anyone you know would like more information on specific applications of this or other Automation technology, Please feel free to contact me.
About David Smith Broadbent Jr.
David Smith Broadbent Jr. is currently the Maintenance Manager/Automation & Controls Systems Integrator at Envirotech Molded Products, a global producer of polymer injection molded products, since January 2017. He also is the Owner at Performance Maintenance LLC, which provides Automation/Controls Integration, Robotics, Vision, SCADA & Enterprise systems services to industry and individuals as well as custom Equipment automation, embedded systems and controls for Manufacturing since March 2007. He was previously the Director of Engineering at Ballard Manufacturing Where he was key in their Transition from a regional Manufacturing facility to a world class global Manufacturing facility from April 2013 to April 2014. David also consults as an industry expert in the Manufacturing equipment & Industrial Automation/Technology fields. He regularly contributes his knowledge & insights to industry groups and platforms.
The content & opinions in this article are the author’s and do not necessarily represent the views of ManufacturingTomorrow
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