Multipoint digital temperature acquisition system
A digitally based system is designed to sense temperatures at a plurality of places and transmit temperature data along a hard-wire cable or distributed (wireless) network to an integrated data collection and control appliance. The system can perform single “spot” measurements or arrange multiple readings in a database for later use. Semiconductor-based sensors with digital output and data transmission capabilities allow large numbers of sensors to be placed along extended lengths of signal cable consisting of only three or four wires. The device incorporates electrical insulating materials, encapsulants, and mechanical strain relief designed to protect the sensors and transmission lines from failures related to exposure to extreme cold. Though described here for cold region applications, the embodiment of this invention encompasses moderate and tropical environments as well, or temperatures ranging from −40 C to +85 C.
1. An apparatus comprising:
a digital environmental temperature sensing module, the module having an elongated, molded housing with first and second tapered ends for receipt of at least one multiple conductor cable, the housing carries an environmental temperature sensor which outputs a digital representation of sensed environmental temperature;
wherein each end is coupled to a multi-conductor cable;
wherein one conductor is coupled to local power supply circuitry to provide electrical energy to the sensing module, a second conductor carries temperature information, and a third conductor is coupled to a local ground reference; and
wherein the local power supply circuitry comprises voltage regulator circuitry, the regulator circuitry provides a selected output voltage to the temperature sensor.
2. An apparatus as in claim 1 wherein the housing includes interface circuits coupled between the sensor and each cable, the interface circuits carry out bidirectional communication with a displaced unit comprising a control appliance.
3. An apparatus as in claim 1 wherein the regulator circuitry reduces an input voltage, from the one conductor to a lower voltage for use by the temperature sensor.
4. An apparatus as in claim 1 further comprising an energy storage element coupled to an output port of the regulator circuitry.
5. An apparatus as in claim 1 which optionally may utilize a fourth conductor to couple an output port of the regulator circuitry to electrical energy input ports of a plurality of sensor modules spaced apart from one another by multiple conductor cables.
6. An apparatus as in claim 1 wherein the ends are sealed to and attached to a respective cable.
7. An apparatus as in claim 6 wherein the sealing and attachment between the housing and respective cables maintains a seal, flexibility and attachment at low temperatures (i.e. to at least −40 degrees C./F.).
8. An apparatus as in claim 1 wherein the temperature sensor and the regulator circuit are carried in the housing by a printed circuit board of a selected length and width.
9. An apparatus as in claim 8 wherein an input set of cable conductors is coupled to the circuit board and an output set of cable conductors is coupled to the circuit board.
10. An apparatus as in claim 1 further comprising a plurality of sensor modules spaced apart from one another by multiple conductor cables.
11. An apparatus as in claim 10 wherein one end of a cable is coupled to a displaced monitoring and control unit.