Which instruments provide direct local indication of the process variable measurement?

In the context of instrumentation, instruments that provide a direct local indication of the process variable measurement are those that allow operators to see the measurement without needing to access a remote system or display. Local indications are typically associated with devices that have an integrated display or gauge that shows real-time data physically at the measurement site.

Local and Remote instruments together signify that while the local instruments provide immediate visual feedback at the measurement point, remote instruments can display the same data elsewhere, often in a control room or another operational area. This functionality is crucial in industrial settings where operators need both instantaneous feedback from the process and the ability to monitor multiple processes from a central location.

In contrast, a transmitter often converts the measurement from a sensor into a signal (analog or digital) for transmission, but it does not inherently provide direct local indication. Similarly, control devices and remote indicators serve different purposes; control devices are typically used to adjust or manage the process based on the measurements received, and remote indicators are designed to display information away from the measurement site. Thus, local and remote instruments collectively represent the best answer as they address both the direct indication at the process variable site and remote monitoring capabilities.