Range low / range high
By Saad, practising automation engineer · Updated 2026-09-25
The engineering-unit values mapped to the bottom and top of a signal span, e.g. 0–10 bar.
Range low is the process value at the bottom of the electrical span (usually 4 mA on a 4–20 mA transmitter). Range high is the value at the top of span (usually 20 mA). Units sit in a separate column: barg, °C, m3/h.
On an IO list, keep Range Low and Range High numeric. 0 and 10 with Units barg means 0–10 barg. SchematicForge prints those three fields next to the transmitter on the loop diagram. They do not change the wiring.
Do not put 4 and 20 in the range columns unless the process units really are milliamps. 4–20 mA is the signal type, not the engineering range.
SchematicForge uses this term in generated loop diagrams, the Loop Register, and termination lists.