Interconnection block diagram is a drawing showing interconnection between each device including instrument, junction box, marshaling cabinet, panel, etc.
This drawing can provide a glance view of overall connection of system. Some interconnection block diagrams provide detail information start from every field instruments up to control system.
In larger project, this interconnection block diagram shows only from junction box / package system to main control system while the connection from junction box to each instrument is shown in junction box wiring diagram.
Interconnection block diagram should also indicate cable number of each cable connecting two devices.
Reference drawing: Instrument and control architecture diagram, instrument cable layout
To prepare an interconnection block diagram, reference should be made to instrument architecture diagram and Instrument cable layout.
Instrument and control architecture diagram shows overall instrument and control system within a plant. Hence by having a look to architecture diagram, the preparation of interconnection block diagram is easier.
Instrument cable layout shows every instruments connection to its junction box.
The purpose of interconnection block diagram drawing
As a reference for preparing junction box wiring diagram/ connection list and marshaling cabinet wiring diagram which both subsequently are required for preparing instrument loop diagram.
Together with instrument cable layout, this drawing is also used as a reference for preparing instrument cable schedule.