On a field mounted controller, how is the setpoint changed?

The process of changing the setpoint on a field-mounted controller is typically conducted by a control room operator. This is because control room operators are responsible for monitoring and adjusting the operational parameters of the system to ensure that processes run smoothly and effectively. They have the necessary understanding and access to the system's operational data and are trained to make these adjustments as needed.

While there are scenarios where setpoints can be changed automatically or remotely, in the context of most operational environments, the role of the operator is crucial. The operator's involvement ensures that adjustments consider real-time data and operational conditions, maintaining optimal performance and safety within the system.

Manual adjustments could be performed directly on the controller, but in many cases, it is the operator who makes these decisions based on their training and understanding of the overall system's needs. Hence, the specific answer regarding the role of the control room operator highlights the importance of human oversight in operational environments.