System and method for automatically adjusting gas sensor settings and parameters

Abstract

An automatic sensor excitation voltage adjustment feature, a multi-range concentration feature, a single calibration feature and a barrier circuit feature. The automatic sensor excitation voltage adjustment feature includes a transmitter having a transmitter microprocessor that provides an initial voltage to a sensor having a sensor microprocessor. As the voltage changes a correction signal is relayed from the sensor microprocessor to the transmitter microprocessor. The correction signal is used to adjust the voltage applied to the sensor. The multi-range concentration sensor feature includes an amplifier associated with the senior/micro-processor to create gain settings used to optimize sensor resolution by changing a gain value for the sensor. This enables use of a single sensor for a variety of different concentration ranges. The single calibration feature enables a sensor to be calibrated at a single gas concentration value, and thereafter be used for a variety of different concentration range applications.

What is claimed is: 
     
         1 . A system for detecting the presence of a gas, comprising:
 a transmitter portion;   a sensor portion; and   a variable voltage supply associated with the transmitter portion and the sensor portion, the transmitter portion to receive information from the sensor portion regarding a received voltage, the transmitter portion to adjust the supplied voltage in response to the information received from the sensor portion.   
     
     
         2 . The system of  claim 1 , the variable voltage supply comprising at least one potentiometer. 
     
     
         3 . The system of  claim 2 , comprising a plurality of potentiometers to enable coarse and fine voltage adjustment. 
     
     
         4 . The system of  claim 1 , the transmitter portion for transmitting information received from the sensor portion to a wired or wireless network. 
     
     
         5 . The system of  claim 4 , wherein the transmitted information includes an identity of at least one sensed gas, and a concentration of the at least one sensed gas. 
     
     
         6 . The system of  claim 2 , comprising a processor associated with the transmitter to set at least one of the plurality of potentiometers to a default value. 
     
     
         7 . The system of  claim 6 , comprising a processor associated with the sensor to communicate to the transmitter processor value of a voltage required by the sensor. 
     
     
         8 . A method for adjusting sensor excitation voltage, comprising:
 providing at a transmitter portion, an operating voltage to a sensor portion;   receiving, at the transmitter, a signal from the sensor portion indicating a voltage required for operation of the sensor portion; and   adjusting, at the transmitter, the operating voltage provided to the sensor portion.   
     
     
         9 . The method of  claim 8 , comprising adjusting the operating voltage using a variable voltage supply. 
     
     
         10 . The method of  claim 9 , the variable voltage supply including at least one potentiometer. 
     
     
         11 . The method of  claim 10 , the at least one potentiometer comprising first and second potentiometers, the first potentiometer for coarse voltage adjustment and the second potentiometer for fine voltage adjustment. 
     
     
         12 . The method of  claim 11 , comprising transmitting information received from the sensor portion to a wired or wireless network. 
     
     
         13 . The method of  claim 12 , wherein the transmitted information includes an identity of at least one sensed gas, and a concentration of the at least one sensed gas. 
     
     
         14 . The method of  claim 10 , comprising setting at least one of the plurality of potentiometers to a default value. 
     
     
         15 . A universal gas sensor/transmitter unit, comprising:
 a sensor portion including a sensor kernel and a processor configured to read a received excitation voltage; and   a transmitter portion having a recess configured to engage the external surface geometry of the sensor, the transmitter including a transmitter processor and at least one power supply circuit for providing adjustable power to the sensor when the enclosure is engaged with a recess of the transmitter; the adjustable power supply circuit including at least one potentiometer controllable by the processor to adjust a power supplied to the sensor portion.   
     
     
         16 . The universal gas sensor/transmitter unit of  claim 15 , the sensor portion including a sensor processor having an associated memory, the memory including a value representative of an excitation voltage of the sensor kernel. 
     
     
         17 . The universal gas sensor/transmitter of  claim 16 , the sensor processor operable to transmit the value representative Of an excitation voltage Of the sensor kernel to the transmitter processor. 
     
     
         18 . The universal gas sensor/transmitter of  claim 17 , the transmitter processor operable to determine a power supplied from the transmitter unit, compare a value of the supplied power to the value representative of an excitation voltage of the sensor kernel, and to make adjustments when the supplied power is different from the value representative of an excitation voltage of the sensor kernel. 
     
     
         19 . The universal gas sensor/transmitter of  claim 16 , the memory containing operational history information for the sensor portion. 
     
     
         20 . The universal gas sensor/transmitter of  claim 15 , file external surface geometry of the sensor portion having a recess for receiving a seal member to seal the external surface geometry of the sensor portion to the recess of the transmitter portion. 
     
     
         21 . A method for calibrating a sensor, comprising:
 setting an original zero offset and a spanning of a sensor at a first gain setting;   obtaining a zero offset at a second gain setting;   obtaining a ratio of the original zero offset to the zero offset at the second gain setting; and   scaling a calibration factor by the ratio to enable operation of the sensor in an operating range associated with the second gain setting.   
     
     
         22 . The method of  claim 21 , wherein the spanning represents 50% of a full scale range of the sensor. cm  23 . The method Of  claim 21 , wherein said sealing a calibration factor comprises re-ranging the sensor and scaling a calibration of the sensor. 
     
     
         24 . A method for providing replacement guidance for a sensor, comprising:
 determining a reduction of sensitivity for a sensor,   trending said reduction of sensitivity over time, and   adjusting a gain parameter associated with said sensor to compensate for said reduction of sensitivity.   
     
     
         25 . The method of  claim 24 , wherein adjusting comprises selecting a gain value from a table of gain values. 
     
     
         26 . The method of  claim 25 , wherein adjusting gain parameters comprises automatically selecting again value from said table. 
     
     
         27 . The method of  claim 25 , wherein adjusting gain parameters comprises a user selection of a gain value from said table. 
     
     
         28 . A method for adjusting an operating range for a sensor, comprising:
 providing: an amplifier associated with said sensor:   providing a table of gain settings for said amplifier; and   selecting a gain setting from said table to optimize a resolution in an analog to digital converter associated with the sensor;   wherein selecting a gain setting adjusts the sensor to one of a plurality of pre-determined operating ranges.   
     
     
         29 . The method of  claim 28 , wherein selecting again setting sets the sensor for operation in a discrete operating range. 
     
     
         30 . The method of  claim 28 , wherein selecting a gain setting is performed in response to a user input. 
     
     
         31 . A system for detecting the presence of a gas, comprising:
 a sensor portion for sending a target gas and providing signals indicative of the gas;   a transmitter portion for transmitting information received from the sensor portion to a network; and   a barrier circuit for limiting at least one of current, voltage and power to the sensor portion.   
     
     
         32 . The network for detecting the presence of one or more gases, the network comprising a plurality of the system of  claim 31 , wherein the multiple systems sense for the same or different gases. 
     
     
         33 . The system of  claim 31 , wherein the sensor portions include an infrared gas sensor, a catalytic bead sensor, an electro-chemical sensor, a photo-ionization sensor, a metal-oxide sensor and combinations thereof. 
     
     
         34 . The system of  claim 31 , wherein the barrier circuit includes a zener diode. 
     
     
         35 . The system of  claim 31 , further comprising a second barrier circuit for limiting at least one of current, power or voltage with the sensor portion. 
     
     
         36 . A method for adjusting sensor excitation voltage, comprising:
 providing, at a transmitter portion, an operating voltage to a sensor portion;   receiving, at the transmitter, a signal from the sensor portion indicating a voltage required for operation of the sensor portion; and   limiting at least one of current, voltage and power to the sensor portion.   
     
     
         37 . The system of  claim 31 , further comprising a plurality of sensor portions.