Delivering fast automation installation
Automation of high fiber horse feed production
“We have used Eaton before for various upgrades, but this was a significant milestone for our business, and it was vital to get it right. SmartWire DT is easy to install and commission and this system enabled us to meet a very tight deadline without any problems. It also gives us great feedback for easier fault finding to help minimize downtime.”
Background
RS Assemblies is based near Bicester, Oxfordshire in the UK. The company produces a number of different high fiber horse feeds for well-known brands. The recipes and mixes it produces vary by brand and in accordance to the specific needs of the horses, depending on their activity and age. Typically, a mix would contain grains, linseed, molasses and a number of other ingredients. The production facility consists of seven silos and ten hoppers containing the raw ingredients, conveyors and mixers. While the production already had a certain level of control using Eaton SmartWire DT and Easy controllers, employees manually added the ingredients to the conveyors that fed the mixers. This made the process very labor intensive and reliant on people following the recipes accurately. A typical eight-hour shift would produce about eight tonnes of horse feed.
Challenge
Due to the popularity of high fiber horse feed, RS Assemblies had to find a way to significantly increase its production. Rodney Hughes, Managing Director of RS Assemblies decided that the whole process needed automating to both increase output and to also remove the chance of human error compromising a recipe. Unfortunately, the business could not afford to be without production if it was going to continue fulfilling its customers’ orders. This meant the Eaton partner, Control Consulting Services Limited (CCSL), and the mechanical contractors had to complete the installation in a series of stages while production continued. For final installation and commissioning of the control system, the plan was to shut down production for just one weekend. The new automated line would then need restarting without any issues whatsoever. Customer Success Story: RS Assemblies Market segment Machine Building In addition, a third party had to provide the software controlling the system on a prespecified PLC and PC platform because the grain moisture content has to be certified if it is being used in animal feed. This meant that CCSL had to integrate the production control with this bespoke software.
Solution
After reviewing the project requirements, Andrew Combstock, Director of CCSL decided that a centrally controlled system from a single panel wouldn’t be the best way forward. Andrew Combstock commented, “A conventional centrally controlled system would have meant the installation of more than 8km of cabling, so we proposed a system that used nine separate control panels each of which would control a specific local area of the new plant. By using SmartWire DT, it meant the final installation used just 3.5km of cabling and saved a lot of time to help meet RS Assemblies’ tight deadline.” The third-party control package contained a PC control system and PLC providing the special requirements for animal food certification. This central system contains all the recipes used by RS Assemblies. Modbus TCP communication was chosen to connect the process control system with the central control panel. This main panel consisted of this PLC connected to Eaton’s SmartWire gateway. A single SmartWire DT cable then connects to each of the nine local control panels. The system, in total, has 232 outputs and 536 inputs plus data from 40 load cells. Each control panel contains local plc as well as digital and analogue input and output modules. The motor control is done through an Electronic Motor Starter EMS that can also be connected directly to the SmartWire DT cabling. In total a combination of 94 modules sit across the system. Safety is controlled via the ESR5 series of safety relays, and all emergency stops are directly monitored via the SmartWire inputs.
This means that the location of any emergency stop operation is instantly identified and then actioned to minimize downtime. Two Eaton DC1 15Kw variable frequency drives control the mixing drums. These were already located in existing control cabinets, so they connect via volt free relay contacts, but there are plans to bring these into the SmartWire network. The load cells provide data from the 10 internal batch hoppers, which is received via 4-20mA signals from the load cell controllers and then sent digitally via Modbus to the PC controller. This data is transmitted through the SmartWire system with a cycle time of 10.67ms for cyclical and 24.38ms for a cyclical data. More than enough to meet the requirements.
Before installation, CCSL produced a detailed Modbus register of all the addresses for these inputs and outputs to ensure they could commission the project with minimal impact on the business. This enabled them to build the control panels and then check and prove most of the signals before the third-party software and PC were installed.
Mr. Hughes commented: “While some of the conveyors were rebuilt when we were still operational, most of the installation had to occur over just one weekend to minimize disruption to our busy production. We closed the plant on a Friday afternoon and reopened it after the weekend. During that time all the equipment had to be moved and installed and the control system commissioned so that we could reopen without any problems on Monday morning.” When it came to the actual installation, by using Eaton’s SWD assist program the allocation of Modbus addresses was instantaneous and the preloaded excel registers were compiled for the plc interface in just a few minutes. “Thanks to Eaton’s SmartWire DT technology, the commissioning of the control panels took just nine hours. A conventional control system would have taken days to achieve this and it would still have needed testing after installation. In this case configuration was preset, so all of the nine control panels could be one hundred percent tested in the works prior to arrival and site installation. This minimized any potential software issues between the SmartWire control system and the pc controller in advance” says Mr. Combstock.
Recognizing the importance of continuous production with minimal downtime, CCSL built all the control panels using GRP enclosures with clear doors for easy inspection as the devices connected to SmartWire DT have a light indicator on top. In case of a fault a visual inspection through the window may provide a first indication on where the problem may be. Each panel also has its own signal tower to show either a healthy or abnormal operation for rapid fault finding.
Results
The new production line reopened without any issues on Monday morning. Commenting on the installation, Mr. Hughes said: “Since we opened the automated production line there has only been one fault, which was due to human error and, thanks to the system, was quickly found and solved.” Production at RS Assemblies has risen from eight tonnes per shift to 35 tonnes since the installation enabling the company to fulfil more orders and win new business. Mr. Hughes continues: “Not only have we significantly improved the overall production volumes for our products, but we have further improved the accuracy of the horse feed mixes by eliminating human error. This installation has given us the capacity to really expand our business since we could easily increase our output to 70 tonnes now by simply adding a second shift.” Currently the company has completed three phases of its expansion plans, with everything now automated apart from the addition of feeding fiber, which is still added manually. Phase four will see this process added in the summer 2019. Mr. Hughes concludes: “We have used Eaton before for various upgrades, but this was a significant milestone for our business, and it was vital to get it right. SmartWire DT is easy to install, and commission and this system enabled us to meet a very tight deadline without any problems. It also gives us great feedback for easier fault finding to help minimize downtime.”
