公开(公告)号：US20230280201A1

公开(公告)日：2023-09-07

申请号：US18168648

申请日：2023-02-14

申请人： Rosemount Tank Radar AB

发明人： Leif Nilsson ,  Tobias Lilja ,  Hans Arkesten

IPC分类号： G01F23/284 ,  G01D21/02

CPC分类号： G01F23/284 ,  G01D21/02

摘要： A field device comprising measurement circuitry; loop current circuitry; voltage measurement circuitry; and a controller configured to: acquire a first value of a process variable; determine if the voltage received by the field device is sufficient to support a first loop current; control, when the voltage is insufficient to support the first loop current, the loop current to an alarm current lower than a predefined alarm threshold current; acquire a second value of the process variable and a present voltage received by the field device; determine a second loop current; determine, based on the present voltage and an estimation of a loop impedance, whether or not the present voltage is sufficient for supporting the second loop current; and control, when it is determined that the present voltage received by the field device from the current loop is sufficient, the loop current from the alarm current to the second loop current.