A differential pressure sensor has been added to the manufacturer's extensive line of hydronic system components. The sensor relays system performance information to a variable-frequency drive or to a building management system. The DPS629 monitors differential pressures of air and compatible gases and liquids. The design uses dual sensors that convert pressure changes into a standard 4-20 mA output signal for two-wire circuits. Its small size and few moving parts make for exceptional response time and reliability, said the company. Terminal block, zero, and span adjustments are easily accessed under the top cover. Designed to meet NEMA 4x (IP66) construction, the unit is applicable for flow elements, heat exchangers, filters, pumps, and coils.