Loop
By Saad, practising automation engineer · Updated 2026-09-25
The complete instrument circuit from field device to controller: sensors, transmitters, cables, terminations, and the controller channel.
On an IO list, one tag is one loop. Two rows with the same tag (for example a valve AO plus two limit-switch DIs) are still one loop with three signals.
SchematicForge stores that as a Loop Register row plus one Signals row per I/O. The loop diagram, cable schedule, and termination list all key off the same tag.
SchematicForge uses this term in generated loop diagrams, the Loop Register, and termination lists.