Michigan Technological University
Name of the energy conservation measure (ECM):
Manufacturing Cell Smart Switching
Purpose of ECM:
Equipment within industrial manufacturing machines and cells are often left running when the cell is not in complete use, contributing to electrical energy waste. A cell usually has one or more primary pieces of equipment that are the ones performing the main manufacturing purpose/process of the cell. When the cell is waiting for parts -- due to upstream stoppages, factory-level part/stock delivery logistics, shift changeovers, part-number changeovers, maintenance events (planned or unplanned), process/system faults, or other reasons -- many auxiliary systems continue running even if the primary machine is shut down.
Auxiliary equipment with rapid startup capability (e.g., a conveyor or vibratory bowl feeder), enhanced with motor soft starters as needed, could be turned off and on during stoppages. Changing PLC programs at the cell level to control individual systems, and idling them when not needed, is the focus of this team’s research.
Description of ECM:
The team looked at the operational focus of PLC control logic an energy-conservation perspective to provide energy efficiency in addition to the conventional focus of operational efficiency. The overall solution includes an upfront assessment phase followed by an implementation phase. The implementation includes software installed as a cell-specific code added to a cell’s PLC since PLCs currently exist industry wide as manufacturing cell controllers. In some cases, implementation may include hardware such as motor soft-starters to enable more frequent motor on-off switching in a safe and efficient manner, and sensors to inform the PLC logic implementing more efficient on-idle-off switching schedules/strategies.
The assessment phase employs a hardware device for acquiring power consumption levels and detailed power-cycle signatures of a primary machine or auxiliary equipment in a cell. It also includes a pair of off-PLC (e.g., Windows-based) software tools for cell-state data acquisition and energy-usage simulation and the authoring of an implementation guide to writing and installing the cell-specific PLC code in the implementation phase.