Abstract: An intrinsically safe data network, such as one defining a system for acquiring and transferring data from inside a hazardous zone at an oil or gas well to outside the hazardous zone, includes a fixed number of at least one data signal conductor and a fixed number of at least one intrinsic safety barrier forming part of the overall network that allows for the use of more transducers than there are intrinsic safety barrier(s).

Abstract: An apparatus and method provide data security for battery backed memory during power up and power down. A reversing sequential power up and power down process is used to control the write process for the memory during the operating voltage transitions of power up and power down. The apparatus is combined in a housing with a microprocessor and a memory to provide an instrument for an oil or gas well.

Abstract: A self-contained multiple channel pressure recorder comprises a single, compact, portable housing containing two quartz pressure transducers and electrical circuits for sensing two pressures communicated into the housing to the pressure transducers, for sensing ambient temperature, and for converting the sensed pressures into electrical signals representing absolute pressure magnitudes compensated both for temperature and calibration effects. The resulting data can be locally displayed through a display mounted on the housing, or the data can be remotely transmitted through an electrical coupling mounted on the housing.