When an automotive company added a new 200-horsepower (hp) rotary screw air compressor and accompanying dryer to a satellite building at its Chicago-area assembly plant, it needed a cost-effective way to integrate the equipment into its existing compressed air network. Doing so would allow plant personnel to easily monitor the air compressor’s performance and ensure it operates in harmony with the plant’s centrifugal air compressors. Importantly, it would contribute to efficient and reliable air compressor operation at all times.
While a complete controls retrofit would have accomplished the technical aim of the project, it would not have been cost effective given the size of the new air compressor. Instead, Bay Controls installed its BayNet control solution on top of the new air compressor’s factory controls. The end result is a communications and control interface that delivers the control and monitoring capability needed at a palatable project cost.
Air Compressors Operated as a Network
The primary compressed air system at the plant consists of six,1,000-hp centrifugal air compressors located in a single air compressor area in the main assembly complex. Each of the centrifugal units is controlled by a Bay Controls V-Series controller, and the air compressors are operated as a network using embedded network logic called, “Distributed Capacity Control” (DCC).
Distributed capacity control has been a signature capability of Bay Controls controllers for over 35 years. It is built on the principle that multi-air compressor systems run their best (and most efficiently) when each air compressor is directly tied to every other air compressor and controlled as a network. Under this control strategy, one or more base-load air compressors run at or near 100% of their capacity while a single trim air compressor ramps up or down in response to fluctuations in plant demand. This provides the dual benefits of consistent pressure regulation and maximum compressed air system efficiency.
Remote Monitoring and Optimization Drive Decisions
The catalyst for the project at the automotive plant was the addition of the new air compressor to a satellite building, which is separate from the main assembly building and the existing compressed air system. A 200-hp Variable Speed Drive (VSD) air compressor was chosen for the facility based on its flexibility and efficiency at part load. Given the plant’s commitment to data-driven efficiency and quantifiable metrics, decision-makers had always intended to integrate the new air compressor into the Tridium Niagara monitoring system. Similarly, even though the air compressor is not directly connected to the larger compressed air system, plant personnel wanted a control solution that would ensure the new air compressor could be controlled remotely to minimize unnecessary runtime.
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Given the physical distance between the main plant and satellite building, the separation of the two compressed air systems, and the project budget, the Bay Controls team decided not to retrofit the new air compressor’s OEM controls with the V-Series controller used with the centrifugal air compressors. The V-Series controller is a proprietary, purpose-built air compressor control system with 33 or 66 input channels, 16 or 32 output channels, and embedded C-link and Modbus communications capability. These specifications make it ideally suited for controlling large, complex air compressors such as the centrifugal units in the main assembly building. The same solution can render it cost prohibitive for smaller, simpler air compressors like the new VSD rotary screw air compressor installed at the plant, especially when the primary objective is monitoring capability and simple on/off remote control.
The Tridium Niagara Network monitors numerous Key Performance Indicators (KPIs) for one of the 1,000 hp centrifugal air compressors in the automotive company’s main plant. Compared to the 200-hp VSD air compressor, the centrifugal unit has many more crucial pieces of instrumentation to monitor and control, which necessitates a more capable controller like the Bay Controls V-Series. Click here to enlarge.
Cost-effective Network Control
In consultation with plant personnel, the Bay Controls team decided its BayNet solution would best meet the goals of the project at a cost that made the project feasible.
BayNet is a control solution that delivers network control and monitoring capabilities to smaller air compressors that don’t require the same level of control capabilities as larger, centrifugal air compressors at a lower price point than stand-alone V-Series control systems. BayNet utilizes a combination of open-source hardware and a customized software platform built using the Tridium Niagara framework. Unlike the V-Series controller, BayNet does not replace the OEM control system. It also does not directly control the air compressor. Instead, it uses the Modbus communications protocol to read monitoring data from the OEM control system and sends on/off control commands, which are ultimately executed by the OEM control system.
Shown are the monitoring points made available through Tridium Niagara for the automotive plant’s 200-hp air compressor and accompanying dryer that were integrated into the main plant's monitoring system. Plant personnel can quickly check the status of the satellite air compressor from anywhere they have Internet access. Click here to enlarge.
For this project, a Tridium Niagara-compatible Industrial PLC from Phoenix Contact was used as the bridge between the air compressor’s OEM controller and the plant’s existing Tridium Niagara network. Utilizing the OEM controller’s Modbus interface, the Phoenix Contact PLC can read all 17 of the air compressor’s control and monitoring points and feed them to the plant’s Niagara network. Once connected to the Tridium Niagara network, the air compressor can utilize all of the existing monitoring, control, and scheduling capabilities the Bay Controls team previously built out for the main compressed air system at the plant.
The automotive company’s Niagara network (as shown) gives plant personnel the ability to control and monitor six, centrifugal air compressors that comprise the main compressed air system at the plant. Personnel can also gain the same level of control and monitoring capabilities for the 200-hp air compressor via the ''Building 2'' tab of the software screen. Click here to enlarge.
Remote Air Compressor is Not So Remote
With the completion of this project, the plant personnel can now remotely monitor and control the new air compressor even though it is located far away from the main compressed air system. This ensures the new air compressor can be operated in harmony – and efficiently – with the main compressed air system, and all of its operating data is captured by the plant’s Tridium Niagara network.
About the Author
Stephen Parry, International Sales Manager for Bay Controls, works with customers in the Western United States and internationally to implement projects built around the Bay Controls suite of products, including air compressor controls retrofits, monitoring solutions, and HVAC integration, email: Stephen.firstname.lastname@example.org, tel: 419-891-4390.
About Bay Controls
For more than 35 years, Bay Controls has been providing control and monitoring solutions to a broad range of industrial, commercial, and government customers in the United States and 60-plus countries across the world. The Bay Controls suite of cloud-ready hardware, and a state-of-the-art, cloud-based analytics platform deliver the actionable intelligence companies need to make smart, data-driven decisions about compressed air system operations, energy savings, and maintenance. For more information, visit www.baycontrols.com.
To read more Air Compressor Controls System Assessments articles visit www.airbestpractices.com/system-assessments/compressor-controls.
To read more Automotive Industry articles visit www.airbestpractices.com/industries/auto.