Patent ID: 8170134
Filing Date: 2012-05-01
Classification: H03M

Abstract:
1. A transmitter for receiving an input of a process variable and converting said process variable into a predetermined output signal by executing a plurality of calculation steps, comprising: a backward calculation means for executing backward calculation of each ordinary calculation step based on the variable calculated at each of said plurality of steps, in addition to a forward calculation means for executing calculation of said plurality of steps; said output signal is given in digital value by a sensor; said sensor is a vibrating differential pressure or a pressure sensor; said backward calculation steps having the following steps: for each step of said plurality of steps, using correction factor c for each step of said plurality of steps, using differential pressure dpcomp that has been corrected in temperature and static pressure and ranges urv and lrv, and said scaled differential pressure dpscaled which has been calculated by said forward calculating means, calculating differential pressure dpcomp′, which has been corrected in temperature and static pressure, using Equation (2) below, for each step of said plurality of steps, using correction factor k for each step of said plurality of steps, using sensor frequencies fc, fr, constants A, B and C, and said differential pressure signal X calculated by said forward calculating means, calculating sensor frequency fc′ using Equation (4) below, c i is a dynamic correction factor having temperature dependence, urv and lrv are user-specified ranges of 100% and 0%, k i is a dynamic correction factor dependent on temperature and static pressure, and A, B and C are constants which represent sensor characteristics.