Multichannel remote transducer monitoring system

Claim 1

An apparatus for monitoring physical phenomena at a remote location comprising: a transducer assembly means including at least two transducer elements, each element varying in resistance as a measurement of change in the physical phenomenon being monitored by said element, a stepper switch having a plurality of contacts and a swinger arm movable along said contacts in a predetermined sequence, each said transducer element coupled to a respective one of said contacts; a single conductor cable means; means for periodically impressing a current pulse of fixed magnitude on said cable means; means for coupling said current pulse from said cable means to said swinger arm; means responsive to the termination of each said current pulse for moving the swinger arm of said stepper switch to the next contact in said sequence; and means for measuring the voltage generated by said current pulse and for indicating said measured voltage, said transducer assembly means further comprising a fixed calibrate resistor element coupled to one of said contacts on said stepper switch and a fixed comparator resistor coupled to said swinger arm such that said comparator resistor is in parallel with each element connected to a respective contact of such stepper switch.

Claim 2

An apparatus for monitoring physical phenomena at a remote location comprising: a transducer assembly means including at least two transducer elements, each element varying in resistance as a measurement of change in the physical phenomenon being monitored by said element, a stepper switch having a plurality of contacts and a swinger arm movable along said contacts in a predetermined sequence, each said transducer element coupled to a respective one of said contacts; a single conductor cable means; means for periodically impressing a current pulse of fixed magnitude on said cable means; means for coupling said current pulse from said cable means to said swinger arm; means responsive to the termination of each said current pulse for moving the swinger arm of said stepper switch to the next contact in said sequence; and means for measuring the voltage generated by said current pulse and for indicating said measured voltage, said transducer assembly means further comprising a fixed calibrate resistor element coupled to one of said contacts on said stepper switch and a fixed comparator resistor coupled to said swinger arm such that said comparator resistor is in parallel with each element connected to a respective contact of such stepper switch.

Claim 4

A method for measuring a plurality of physical parameters by means of a transducer assembly positioned at a remote location and connected to a near location via a single conductor cable means at its near end, said transducer assembly connected to the remote end of said cable means, said assembly including a stepper switch and a plurality of transducer elements, comprising the steps of: (a) switcing said stepper switch to a first switch contact having no transducer element connected thereto in response to the termination of a current pulse on said cable means, said stepper switch being coupled with a fixed comparator resistor; (b) coupling a constant current pulse on said cable means at its near end thereof and measuring the voltage generated on said cable means thereby; (c) switching said stepper switch to a second switch contact having a fixed value calibrate resistor connected thereto in response to the termination of the current pulse of step (b); (d) coupling a constant current pulse onto said cable means at its near end thereof and measuring the voltage generated on said cable means thereby; (e) switching said stepper switch to a predetermined next switch contact having a transducer element connected thereto, in response to the termination of the current pulse on said cable means generated in the previous step, each transistor element resistively varying as a function of the variation in the respective physical parameter such transducer element is monitoring; (f) coupling a constant current pulse onto said cable means at its near end thereof, and measuring the respective voltage generated on said cable means by such element thereby; (g) repeating of steps (e) and (f) for each transducer element connected to said stepper switch at said remote end of said cable means; and (h) repeating of steps (a)-(g).

Claim 5

A method for measuring a plurality of physical parameters by means of a transducer assembly positioned at a remote location and connected to a near location via a single conductor cable means at its near end, said transducer assembly connected to the remote end of said cable means, said assembly including a stepper switch and a plurality of transducer elements, comprising the steps of: (a) switcing said stepper switch to a first switch contact having no transducer element connected thereto in response to the termination of a current pulse on said cable means, said stepper switch being coupled with a fixed comparator resistor; (b) coupling a constant current pulse on said cable means at its near end thereof and measuring the voltage generated on said cable means thereby; (c) switching said stepper switch to a second switch contact having a fixed value calibrate resistor connected thereto in response to the termination of the current pulse of step (b); (d) coupling a constant current pulse onto said cable means at its near end thereof and measuring the voltage generated on said cable means thereby; (e) switching said stepper switch to a predetermined next switch contact having a transducer element connected thereto, in response to the termination of the current pulse on said cable means generated in the previous step, each transistor element resistively varying as a function of the variation in the respective physical parameter such transducer element is monitoring; (f) coupling a constant current pulse onto said cable means at its near end thereof, and measuring the respective voltage generated on said cable means by such element thereby; (g) repeating of steps (e) and (f) for each transducer element connected to said stepper switch at said remote end of said cable means; and (h) repeating of steps (a)-(g).