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Easy Automation And Monitoring With All-In-One PLC Improves Machine Safety

Cost-effective automation solution for a sustainable and energy efficient future
craneEnergy Plant Solutions of Palmerston North, New Zealand specializes in the supply and installation of industry energy plants. Their goal is to provide high-efficiency products, for a sustainable and energy efficient future.

To achieve that goal, they needed a cost effective automation solution for their range of package boilers; this solution would control all of the functions of the boiler, including feed pumps, pressure control and level control. They hoped that by standardizing their boiler control systems with an all-in-one PLC+HMI they could reduce development time and improve efficiency.

EPS selected Unitronics programmable logic controller with integrated HMI; this controller has an 10.4-inch color touchscreen and function keys. They also added almost a hundred local I/O points, both digital and analog, using I/O expansion modules. Due to the high I/O count and communication needs, the PLC large screen was a necessity, offering room to display important information without crowding the screen.

"Working with the Unitronics combined PLC and HMI make other systems feel old fashioned and obsolete…"

Energy PlantThe programmable logic controller uses discrete I/O to control the burner. EPS was particularly interested in automating key safety procedures; for example, the PLC shuts the burner down when certain alarms are triggered. They also use the PLC to monitor and log data on the burner’s operation, including actuator positions, burner fan speeds, flue gas residual oxygen, fuel valve states and fault details. This trend data is stored using the PLC SD card functionality. EPS also uses the SD card to store set back up points, enabling a quick recovery in the unlikely event of a hardware failure.

In addition the, if a fault condition triggers an alarm, the programmable logic controller sends an SMS message to a list of operators in sequence to inform them of the condition. The operator receives an actual description of the fault, rather than a generic “boiler fault” message, allowing him to assess how urgent the response needs to be. Responding to the SMS alert, prevents the message being sent to the remaining operators on the list.

EPS can remotely access any of the PLCs installed on one of their boilers using Unitronics complimentary software utilities. Justin Butler, Senior Electrical Engineer, explains the advantages, saying “With Remote Operator, we can see exactly what the operator sees from our office at the other end of the country via a VPN at absolutely no cost either financially or in development time. This is a huge advantage if the client requires assistance to solve a problem.”

Furthermore, using Unitronics PLC+HMI enabled EPS to easily simulate their applications before installing them in the field. Justin Butler explains, “Unitronics PLCs allow us to run the PLC without any I/O attached…We can enter any values we like for conditions and test that the PLC acts as intended…This means we can do 90% of the testing before we even go to the site.”

This advanced testing means that EPS avoids solving problems last minute, in the field, which saves them time and effort.

Butler notes that Unitronics PLCs also offer significant savings. He explains that these saving consist of both “the development software licensing (it doesn’t get much cheaper than free) and also in the time required to develop the PLC/HMI software. "The programmable logic controller is programmed with Unitronics PLC+HMI All-in-One software, which provides a single environment for ladder logic, HMI design, and communication configuration. Butler says, “Making changes is so much quicker when you can add the necessary logic to the PLC program and then immediately add the new elements to the HMI without having to export or import tag data, etc.”

He continues, saying “Working with the Unitronics combined PLC and HMI make other systems feel old fashioned and obsolete. The support from Unitronics, from our local supplier, to email support, to help ideas on the forum, has been absolutely fantastic.”

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