Multiple instruments within a loop share a common what?

In a control system, multiple instruments within a loop share a common loop number. This loop number is a crucial identifier that helps differentiate and organize the various instruments and devices in a process control system. Each instrument in a loop is connected to a specific control system, which maintains the data flow and communication needed for effective monitoring and control.

The loop number plays a vital role in ensuring that all instruments within that loop can be accurately referenced and managed by the system, allowing for efficient data collection and process control. This common identifier simplifies maintenance and troubleshooting, as technicians can easily locate and address issues within the specific loop.

In contrast, the other options like loop prefix, loop suffix, and installation detail do not serve as unique identifiers for multiple instruments within a loop. Additionally, while installation details may pertain to specific instruments, they do not provide a standardized way of identifying an entire collection of devices working together in a control loop.