Abstract: A pneumatic output signal limiting device utilizing a planar-type construction having a balance beam with a passage extending through the area of its pivotal axis to provide communication between side-by-side chambers and arranged so that the balance beam moves into contact with a valve in the output chamber to close the passage and further movement in the same direction open a vent. In operation, the output signal equals the input signal when the input signal is within one limit of a preselected output signal operating range. When the input signal equals the limit, the passage is closed and the output signal is maintained equal to the limit. The passage remains closed when the input is outside the limit and the output signal is maintained equal to the limit until the input signal is a preselected value outside the limit. Then the balance beam moves in the same direction to open the vent and reduce the output signal to the vent pressure.