Abstract: A two-wire transmitter having a detecting section for detecting a physical variable to be measured to produce a detection output, first and second constant voltage devices connected in series with a two-wire transmission path, a signal processor driven by a voltage supplied by the first constant voltage device for converting the detection output into representative serial pulse signals and a switching circuit which is connected in parallel with the second constant voltage device and is turned on and off by the serial pulse signals to produce corresponding output signals from the transmitter on the two-wire transmission path by utilizing a current flowing in the two-wire transmission path while enabling the transmitter to connect in a single loop with another two-wire transmitter.

Abstract: A remote seal-type pressure signal generator has a pressure measuring end having a sealing diaphragm facing a pressure to be measured, a pressure detector body connected to the pressure measuring end through a first capillary tube, the detector body having a pressure-receiving space in which a pressure transmitting medium is liquid-sealed and pressure detecting means for detecting an internal pressure of the pressure-receiving space by way of a pressure difference thereof with respect to a pressure of a second pressure-receiving space to which a second pressure is applied, and a flexible protective pipe covering the capillary tube between said detector body and said pressure measuring end, a second capillary tube is housed in the protective tube, and extending from the second pressure-receiving space in the detector body while having substantially the same length as the first capillary tube, and having a distal end closed in the vicinity of the pressure measuring end, with the pressure transmitting medium bei