×

Controlled DC current supply device with open circuit detecting means

  • US 4,086,570 A
  • Filed: 04/08/1976
  • Issued: 04/25/1978
  • Est. Priority Date: 04/21/1975
  • Status: Expired due to Term
First Claim
Patent Images

1. In a control system of the type comprising controller means for providing a control signal on a signal line, and DC output means for converting the control signal on the signal line into a DC current output signal for supply to a current loop including one or more load devices, the improvement which comprises:

  • open-circuit detecting means for detecting an open circuit condition in the load current loop;

    shorting means in the DC output means for shorting the signal line in response to detection of an open-circuit by the open circuit detecting means; and

    level detecting means for detecting the shorting of the signal line;

    whereby an indication of an open-circuited load condition may be supplied back to the controller means without use of an added signal carrying line.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×