×

Interrogation device

  • US 4,578,539 A
  • Filed: 08/10/1983
  • Issued: 03/25/1986
  • Est. Priority Date: 07/22/1983
  • Status: Expired due to Fees
First Claim
Patent Images

1. An interrogation unit for connecting into an installation via sensing elements connected to sense required information in the installation, said interrogation unit having signal supplying means for supplying signals indicative of the condition of each of various sensors in the installation, and trigger circuit means activatable upon recipt of a request signal to transmit said signals for each of the sensors in turn, said signal supplying means including tone generating means which generates two different tones and being connected to either transmit said tones or not to transmit said tones, whereby to indicate that any particular sensor has changed from its initial condition or not, a first of said tones being used for identifying a group of sensors whilst the second of said tones being used for identifying particular sensors in that group.

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