The production of glass is an elaborate and sophisticated process so the companies involved often use PLCs with the bus technology in its control mode. Overall, the PLC is applied in both analogue data recording in the glass production, and in digital quality and position control. In the paper industry, PLCs are used in various processes. These include controlling the machines that produce paper products at high speeds. For instance, a PLC controls and monitors the production of book pages or newspapers in offset web printing.
Manufacturing cement involves mixing various raw materials in a kiln. The quality of these raw materials and their proportions significantly impact the quality of the final product.
To ensure the use of the right quality and quantities of raw materials, the accuracy of data regarding such process variables is of the essence. The PLC in particular, controls ball milling, coal kiln and shaft kiln.
Other examples of PLC programming applications that are in use in various industries today include water tank quenching systems in the aerospace sector, filling machine control system in the food industry, — industrial batch washing machine control and closed loop textile shrinkage systems.
PLC is also used in the coal-fired boiler fan change-over system in hospitals, corrugation machine control system and silo feeding as well as injection moulding control systems in the plastic industry. Contact Us. Company About Us History Partners. What is a PLC? These controllers eliminated the need for rewiring and adding additional hardware for each new configuration of logic.
The new system drastically increased the functionality of the controls while reducing the cabinet space that housed the logic. Perform Housekeeping activities such as Communications, Internal Diagnostics, etc.
Program Scan Executes the user created program logic 3. Housekeeping This step includes communications with programming terminals, internal diagnostics, etc Normally, in local plant and manufacturing environments, this type of communication method is perfectly fine, since the communication distances are short and predominantly hardwired.
With poll-response, PLCs are constantly communicated with to check for any data changes. As the Industrial Internet of Things IIoT becomes more popular, there is an increased need for data from remote locations. This translates to more PLCs and computing devices at the edge of the network. Communication with edge devices involves long distances in which cellular networks are used more frequently. Due to the high frequency of poll-response communication, cellular network would incur an incredibly high cost.
To address this issue, solutions such as MQTT employ a publish-subscribe protocol to streamline communications from the edge of the network. This improves bandwidth usage and makes PLC data from edge-of-networks widely available throughout the organization. The industry continues to see new products entering the market ranging from devices like Programmable Automation Controllers PACs which combine the functionality of PLCs with higher-level PC functionality all the way to industrial embedded hardware.
Even with these new products, PLCs remain popular because of their simplicity, affordability, and usefulness. And software like Ignition will enable organizations to maximize their usefulness for many years to come. Ignition seamlessly connects data from the plant floor to the top floor, and everywhere in between. We built Ignition from the ground up to improve the processes for every industrial professional in virtually every industry.
There is talk in the water industry, for example, of framework suppliers having to be able to assure support of control systems for up to 20 years. Of course the control hardware will change over that time but PLC users have the peace of mind of knowing that the software will always port to the latest controller. The modern industrial PC provides a stable computing platform and it would be unfair to suggest that it locked-up and crashed with the unerring regularity of a desktop PC.
However, it is not on equal terms with a PLC. The real time operating system that runs alongside Windows on a typical industrial PC has been designed to try to provide the same level of robustness as you get from a PLC CPU.
If a PC operated in complete isolation, perhaps that would be the end of the reliability debate. Will the drivers for all of these products have been tested in combination and thoroughly proved? It seems unlikely. Clashes can and do occur and problems can be exacerbated every time those drivers are updated. It is almost inevitable, then, that an industrial PC will crash and what might that mean for the control process?
By contrast, when did you last hear of anyone needing to reboot a PLC after a software crash — probably never…. In such applications, the PLC represents a highly affordable solution, much more so than an equivalent PC-based system. The customisation potential of the PLC is enormous, with numerous ways to expand the functionality but all without ever leaving a common platform.
In between, there are those applications that might start small, perhaps written in ladder but then grow as the application evolves — taking advantage of the scalability of the PLC platform — benefiting from the ability to write the control program in structured text and to drag and drop software function blocks that will take away much of the configuration effort. Integration of other automation equipment. For many automation engineers, there is never any need to move outside the product portfolio of a single vendor, with suppliers such as Mitsubishi Electric able to address every requirement from HMIs, drives, servos, motion control, safety and robotics to low voltage power distribution products, power management meters and CNC systems.
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