System and method for detecting fluid in terminal block area of field device
AssigneeRosemount Inc.
InventorDavid L. Wehrs
Life of this patent
Estimating the term…
Abstract
A field device detects the presence of fluid in the terminal block area of the field device by generating an alternating current (AC) test current signal and measuring the amplitude of the resulting AC voltage signal. The field device includes a first terminal and a second terminal adapted for connection to a control room through a twisted-wire pair current loop. Impedance of the current loop is increased by the presence of fluid between the first terminal and the second terminal. By providing an AC test current signal to the control loop and measuring a resulting AC voltage magnitude, the impedance of the control loop can be determined. Increased impedance in the control loop indicates the presence of water in the terminal block.
Claims23
A method of detecting fluid in a terminal block of a field device, the method comprising:
- applying an alternating current (AC) test signal between a first terminal and a second terminal within the terminal block of the field device;
- measuring a resulting AC voltage magnitude in response to the AC test signal;
- and
- detecting the presence of fluid in the terminal block based on the measured AC voltage magnitude.
A field device which detects fluid within a terminal block area of the field device, the field device comprising:
- a first terminal and a second terminal connected to communicate with a control room;
- a current regulation circuit connected between the first and second terminal for generating an alternating current (AC) test signal at a selected frequency;
- and
- an AC measurement device connected to measure a resulting AC voltage magnitude generated in response to the AC test signal provided by the current regulation circuit, wherein the presence of fluid within the terminal block area is detected based on the measured AC voltage magnitude.
A system for detecting the presence of fluid in a terminal block area of a field device, the system comprising:
- means for applying an alternating current (AC) test signal between a first terminal and a second terminal within the terminal block of the field device;
- means for measuring a resulting AC voltage magnitude in response to the AC test signal;
- and
- means for detecting the presence of fluid in the terminal block based on the measured AC voltage magnitude.
Dependencies are inferred from the claim text.