Abstract: A sensor module supplying analog data signals from one of a temperature or pressure sensing element connects to a modular switch system through a D-shaped sensor port in the modular switch housing. The manufacturer and user may modify the standard modular switch system, which includes an internal electrical assembly to be a pressure or temperature switch by applying and removing selected sensor modules. The interconnection between the sensor module and the modular switch system includes particular leads carrying analog data signals and serial digital information signals. These leads are attached to a connector secured to the sensor module substrate. The connector is enclosed in a D-shaped extended portion of a cover which snap fits to an open end of the sensor module base. Mounted on the sensor module substrate are an amplifier, a reference voltage circuit and a non-volatile memory containing calibration data relating to the standardization of output signals from the sensors.

Abstract: A modular switch device includes a housing enclosing an interconnected control module, a display module and a power module. A sensor module supplying analog data signals from one of a temperature or pressure sensing element connects to the control module through a passage in the housing. A user connects his electrical wires and electrical power to the electrical assembly within the housing through an opening. The user can select between AC and DC switched output modules and the presence or absence of a 4-20 milliampere output module by plugging and unplugging same from wells provided in the housing. The manufacturer and user thus can modify the standard housing, which includes an internal electrical assembly to be a pressure or temperature switch and to provide selected output switch characteristics by applying and removing selected sensor and output modules thereto.