System for remotely indicating selectably two phenomena

Claim 1

A system for selectably indicating at a control location two phenomena associated with a device wherein the device is separated from the control location and in which two conductive elements extend from the control location to the apparatus, comprising: a. a control assembly at said control location, said control assembly including: 1. a two-pole DC voltage source; 2. a DC current measuring device in series with one pole of said DC voltage source; 3. a double-pole, double-throw switch having one pole in series with said current measuring device and the other pole in series with the other pole of said DC voltage source, said switch having contact points engaged by said switch poles; 4. a reactance means having a high reactance to AC current flow and a low resistance to DC current flow, said reactance means being connected between one of said conductive elements and said switch contact points and a conductor extending from said switch contact points to the other of said conductive elements, said switch contact points being arranged so that in one switch position said DC voltage source induces DC current flow in one direction through said conductive elements and in another switch position DC current flow is induced in another direction through said conductive elements; and b. a measurement assembly at said electrical device including 1 a first sensing element providing a varying resistance in response to a first phenomenon; 2 a first diode in series with said first sensing element; 3 a second sensing element providing a varying resistance in response to a second phenomenon; 4 a second diode in series with said second sensing element, said sensing elements and diode members being connected in parallel with said diodes being in opposed current conductive relationship, said paralleled sensing members and diodes being connected between said conductive elements whereby when said switch is in one position DC current flows through said current measuring device and one of said sensing elements according to the polarity of the said diode in series therewith to register on said current measuring device an indication of the resistance of said one of said sensing elements and when said switch is in the other position current flows through the other of said sensing elements to register on said current measuring device an indication of the resistance of the other of said sensing elements.

Claim 2

A system for selectably indicating at a control location two phenomena associated with a device wherein the device is separated from the control location and in which two conductive elements extend from the control location to the apparatus, comprising: a. a control assembly at said control location, said control assembly including: 1. a two-pole DC voltage source; 2. a DC current measuring device in series with one pole of said DC voltage source; 3. a double-pole, double-throw switch having one pole in series with said current measuring device and the other pole in series with the other pole of said DC voltage source, said switch having contact points engaged by said switch poles; 4. a reactance means having a high reactance to AC current flow and a low resistance to DC current flow, said reactance means being connected between one of said conductive elements and said switch contact points and a conductor extending from said switch contact points to the other of said conductive elements, said switch contact points being arranged so that in one switch position said DC voltage source induces DC current flow in one direction through said conductive elements and in another switch position DC current flow is induced in another direction through said conductive elements; and b. a measurement assembly at said electrical device including 1 a first sensing element providing a varying resistance in response to a first phenomenon; 2 a first diode in series with said first sensing element; 3 a second sensing element providing a varying resistance in response to a second phenomenon; 4 a second diode in series with said second sensing element, said sensing elements and diode members being connected in parallel with said diodes being in opposed current conductive relationship, said paralleled sensing members and diodes being connected between said conductive elements whereby when said switch is in one position DC current flows through said current measuring device and one of said sensing elements according to the polarity of the said diode in series therewith to register on said current measuring device an indication of the resistance of said one of said sensing elements and when said switch is in the other position current flows through the other of said sensing elements to register on said current measuring device an indication of the resistance of the other of said sensing elements.