The International Society of Automation’s (ISA) Loop Signal and Process Variable tool helps automation and control professionals solve for a process variable or its associated loop signal. This tool lets control system integrators and technicians choose from a variety of engineering units (e.g., pressure, temperature, level, flow) and process signals (e.g., 4-20 mA or 1-5 VDC). The app calculates for a variety of other engineering units and process signals. If a process variable (PV) is known and its associated loop signal is also known, then you can solve for an unknown of any other PV or loop signal within its range.