A transducer assembly for connection with a digital signal processing system includes an analog transducer, a digital connector assembly movable relative to the analog transducer to facilitate connection with the digital signal processing system, and a cable permanently affixed between the analog transducer and the digital connector assembly to convey an analog transducer signal therebetween. The digital connector assembly includes a connector housing, a digital connector mounted by the connector housing to mate in a detachable manner with the digital signal processing system, and transducer interface circuitry disposed within the connector housing in a non-removable manner and including a digital storage device programmed to store digital transducer data, such as transducer identification, configuration settings and calibration or correction factors, for retrieval by the digital signal processing system. The transducer interface circuitry can also include signal conditioning circuitry and a microcontroller. Incorporating the transducer data memory and interface circuitry in the connector housing allows conventional transducers to be used without modifying existing mounting techniques and, at the same time, provides traceability of the transducer and its calibration data.

Transducer assembly with smart connector

A method and apparatus features a system for automatically monitoring the operating environment and other physical conditions around and in which a host computer system operates Sensors located around a computer system, including inside equipment cabinets and under the floor where cabling and air are ducted, are used to collect data that is frequently and periodically collected and stored along with an indication of the time and data of collection The stored data is checked against a list of environmental parameters for the location of each sensor and an indication given when measurements indicate an environmental condition is outside discrete limits and rates of change of conditions The stored parameters may be changed at any time from a console of the computer system The stored data is also used to prepare histograms that are used to indicate trends in environmental conditions that can point to potential problems that may then be remedied before actual problems arise, and to faulty computer system installation design Generation of histograms may be requested from remote locations via telephone links and then forwarded over the links to the remote locations for analysis Trouble conditions indicated by out of parameter limits checking causes alarms to be given at the computer site and to be selectively sent to remote sites to initiate remedial action In addition, a failsafe monitoring operation monitors the communications between the computer system and the monitoring apparatus to detect troubles

Method and apparatus for monitoring the operating environment of a computer system

A transmitter (10) in a process control system includes input/output circuitry (74) for coupling to a process control loop (12). A first sensor (40L) having a first impedance is responsive to a first sensed parameter. A second sensor (40H) having a second impedance is responsive to a sensed parameter. First and second excitation signals (S1, S2) are applied to the first and second sensors (40L, 40H). A summing node (44) sums the outputs (OL, OH) of the first and second sensors (40L, 40H). An analog to digital converter (54) provides a digital output representative of the summed signals. Digital signal processing circuitry (70) coupled to the analog to digital converter (54) provides an output related to the outputs (OL, OH) of the first and second sensors (40L, 40H) to the input/output circuitry (72) for transmission over the process control loop (12).

Process control transmitter

The present invention is for digital calibration of plug-in transducers and the like. The invention comprises means for digitally storing error-correcting tables in a physical location which is associated with the transducer, and a means for interpreting those tables.

Apparatus for digital calibration of detachable transducers

A smart sensor module includes a microcontroller and a signal conditioning integrated circuit. In a preferred embodiment, the signal conditioning integrated circuit is a mixed signal application specific integrated circuit (ASIC) incorporating an instrumentation amplifier, offset correction, sensitivity correction, low pass filtering, an analog-to-digital converter (ADC), a temperature sensor, digital I/O interface, a crystal oscillator circuit, and power on reset open collector output. The ADC can be multiplexed to the transducer, the temperature sensor or an external input. All features of the ASIC can be dynamically reconfigured at any time by the microcontroller. Offset correction is implemented with a 4-bit coarse adjustment digital-to-analog converter (DAC) and a 7-bit fine adjustment DAC to control the instrumentation amplifier reference voltage. The coarse adjustment allows compensation of sensor-to-sensor offset variations, while the fine adjustment allows dynamic or real-time compensation of temperature-induced variations. The sensitivity correction is accomplished with a programmable system gain configured as a coarse gain adjustment and a fine gain adjustment. The coarse gain adjustment allows compensation of sensor-to-sensor sensitivity variations. The fine gain adjustment allows dynamic or real-time compensation of temperature-induced sensitivity variations. The smart sensor module allows very precise calibration of the sensor, signal processing capabilities, decision making capability and serial interface capability.

Smart sensor module

A method of digital temperature compensation uses a digital temperature compensation word to produce a digital word modification of a digital input to a temperature sensitive digital to analog converter hereinafter converter. The method includes the steps of sensing the temperature affecting the converter to produce a digital temperature representation which is used by a digital computer to produce an output in accordance with a characterization equation in the form of Output=f(D, M) where D=digital data and M=f(temperature). The temperature stability of the converter is affected by the temperature stability of a reference voltage circuit used in the converter and having a voltage reference diode. A compensation circuit uses a temperature sensor in the form of a second diode, which is thermally coupled to the reference diode, and a tracking type analog-to-digital converter for converting an analog signal. The output of the analog-to-digital converter is supplied as a digital word to a digital computer system which uses the digital word to modify a digital input to the converter. The computer system includes a non-volatile memory in which is stored a characterization equation which describes the performance of the converter as a function of the digital output signal from the computer and the digital representation of temperature from the analog-to-digital converter. Thus, the output from the digital-to-analog converter is compensated for the effect of temperature on the converter.

Method of digital temperature compensation and a digital data handling system utilizing the same

A power supply structure for an electronic system includes a primary power source and a stand-by or secondary power source. The secondary power source is ground circuit isolated from the primary source. A monitoring circuit, which is energized from the secondary source is connected to monitor the primary source for incipient failure, then to produce an output signal which may be used to trigger an alarm and/or switch the secondary power source into energizing connection with respect to the electronic system.

D.C. monitoring circuit

A sensor communication system uses a shared analog signal to duty cycle converter for producing a comparison between a predetermined free-running triangular waveshape and a selected output signal from a plurality of analog signal sources such as process sensors, to convert the amplitude of the analog signal to a variable duty cycle signal. The variable duty cycle signal is subsequently converted to a digital signal which may be represented by a count stored in a counter counting clock pulses during the occurrence of the pulse width waveshape of the variable duty cycle signal. The digital signal is utilized as a digital word by a microprocessor operating in accordance with a stored program to produce a characterized digital output signal for use in a communication after conversion to a 4-20 ma control signal for communication and control in an industrial process control system. One of the signal sources may be from a circuit having temperature and time drift components whereby the corresponding digital word is used by the microprocessor to compensate the digital words from the other analog signal sources.

Sensor communication system

A multi-input signal comparator and indicator circuit for comparing a plurality of signal levels with a reference level and an indicator circuit arranged to respond to a comparator output signal for indicating an error in any of the comparator input signals. A high and a low comparator is used for each input signal to provide a "window" comparison while separate indicators provide a readout of high and low errors.

Theodore B. Bozarth

Papers

Method of digital temperature compensation and a digital data handling system utilizing the same

D.C. monitoring circuit

Sensor communication system

Multi-input signal comparator and indicator circuit

Method and apparatus for temperature compensation in a digital data handling system