Differential Pressure Transmitter - SmartLine STD700 SmartLine®ST700 Differential Pressure Transmitters bring smart technology to a wide spectrum of measurement applications ranging from furnace combustion airflow rate to hydrostatic tank gauging. Part of the SmartLine® family of products, the STD700 is suitable for monitoring, control and data acquisition featuring piezoresistive sensor technology. By combining pressure sensing with on chip temperature compensation