In todayas competitive markets, manufacturers strive to continually improve manufacturing performance to meet their business needs and goals. As process control loops have a major impact on a plantas financial performance, focusing on loop performance is critical. This technicianas guide defines loop checking in the broader scope of control loop performance in addition to the more traditional terms of the plant startup. It discusses general methods and practices that can be applied across many processes/industries. Featured topics include: loop checking basics, factory acceptance testing, wiring and loop checks, performance benchmarking, and sustaining performance.