Abstract: A zero and span adjustment circuit for current to pressure transducers. Current sources in parallel with the transducer bypass current around the transducer. One current source includes a variable resistor for adjusting the zero set point independently of the input current signal. The other current source includes a variable resistor for adjusting the span of the output pressure proportional to the input current signal. A feedback resistor couples a feedback signal from the transducer current to the other current source to vary the bypass current.

Abstract: An electric signal in an electrical level measuring transducer shall be generated in an explosion-proof manner, which continuously depends on the level in the interior of a container. The buoyancy of a float 14 is converted into a movement of a permanent magnet 36. The permanent magnet moves in the area of a Hall generator 44. The signal processing elements 48 are disposed in a tightly closed housing in explosion-proof manner. The Hall generator 44 is located in a non-magnetic part of the wall 38 of the housing 20.

Abstract: The housing of a reed switch, actuatable by magnetic flux, is supported at the ends by grommets fitting snugly inside an aluminum sleeve. The switch terminals extend from the housing adjacent a closed end of the sleeve, have lead wires soldered to them and are in an embedment of silicone rubber. A cable having electric lines projects into an open end of the sleeve. After passing through an insulating spacer plate the wires are soldered to the cable lines. The portion of the sleeve between the open end and the adjacent grommet is filled with a silicone rubber embedment. The sleeve is positioned in a bore in a mounting body and adjacent a side of the body is a float responsive magnet.