×

Field transmitter built-in test equipment

  • US 5,481,200 A
  • Filed: 09/15/1993
  • Issued: 01/02/1996
  • Est. Priority Date: 09/15/1993
  • Status: Expired due to Term
First Claim
Patent Images

1. A measurement transmitter coupling to a two-wire process control loop, comprising:

  • two terminals for coupling to the two-wire process control loop;

    a sensor for sensing a process variable;

    circuitry for transmitting the process variable over the two-wire loop;

    current setting circuitry for setting a current through the two-wire loop to a first current level and to a second current level;

    voltage sense circuitry providing a sensed voltage output related to a sensed voltage potential between the two terminals; and

    a microprocessor coupled to the voltage sense circuitry and the current setting circuitry for calculating loop resistance of the two-wire current loop based upon a difference between the first and second current levels and a first voltage potential sensed at the first current level and a second voltage potential sensed at the second current level.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×