Patent application number | Description | Published |
20100177800 | PROCESS TEMPERATURE TRANSMITTER WITH IMPROVED TEMPERATURE CALCULATION - In a process temperature transmitter, a method for providing a process temperature output is described. The method includes providing a measurement current through a circuit including a reference resistor and a resistance temperature device (RTD). A first voltage across the reference resistor is measured while the measurement current flows through it. A first voltage across the RTD is also measured while the measurement current flows through it. A first resistance of the RTD is calculated based on the measured voltage across the reference resistor and the measured first voltage. A first process temperature output is provided based on the first resistance of the RTD. A second voltage is subsequently measured across the RTD while a measurement current flows through it. A second voltage across the reference resistor is then estimated based on the measured second voltage across the RTD and the measured first voltage across the reference resistor. A second resistance across the RTD is calculated based on the measured second voltage and the estimated second voltage. A second process temperature output is provided based on the second resistance. | 07-15-2010 |
20110071794 | INDUSTRIAL PROCESS CONTROL TRANSMITTER WITH MULTIPLE SENSORS - An industrial process control transmitter includes a first input configured to couple to a first sensor, and a second input configured to couple to a second sensor. Measurement circuitry is configured to couple to the first and second sensors and provide an output related to a sensed process variable. A multiplexer is configured to selectively couple the first and second sensors to the measurement circuitry. An equalizer circuit is coupled to the first and second sensors and configured to equalize a voltage potential between the first sensor and the measurement circuitry. | 03-24-2011 |
20110299567 | PROCESS VARIABLE TRANSMITTER WITH THERMOCOUPLE POLARITY DETECTION - A process variable transmitter for measuring a temperature of an industrial process, includes a first electrical connector configured to couple to a first wire of a thermocouple, the first electrical connector includes a first electrode and a second electrode. The first and second electrodes are configured to electrically couple to the first wire of the thermocouple. A second electrical connector is configured to couple to a second wire of the thermocouple, the second electrical connector includes a third electrode and a fourth electrode. The third and fourth electrodes are configured to electrically couple to the second wire of the thermocouple. The second wire is of a different material than the first wire. Measurement circuitry is coupled to the first and second electrical connectors configured to provide an output related to a temperature of the thermocouple. The measurement circuitry is further configured to identify polarity of thermocouple based upon at least one measurement taken between at least two of the first, second, third and fourth electrodes. | 12-08-2011 |
20120245895 | DEGRADING SENSOR DETECTION IMPLEMENTED WITHIN A TRANSMITTER - A process variable transmitter includes a memory that stores a filtered sensor value that is calculated based on a prior received sensor value and a filtered rate of change value that is calculated based on a prior rate of change value. The process variable transmitter also includes a controller that receives a sensor value and compares it to the filtered sensor value to obtain a rate of change value. The controller also compares the rate of change value to the filtered rate of change value to obtain a deviation value, and generates an output indication, such as a sensor failure warning output, based on the deviation value. This is done within the process variable transmitter. | 09-27-2012 |
20120250781 | DYNAMICALLY ADJUSTED A/D RESOLUTION - A process variable transmitter is used to measure a process variable, and, in doing so, dynamically changes the resolution of the A/D converter based upon the measured value of the analog input signal. This can be done by automatically adjusting the configurable resolution gain adjustment based on the value of the analog signal being measured, by normalizing the input signal being measured so that it is centered in an optimal resolution window of the A/D converter, or by adjusting a voltage reference provided to the A/D converter. | 10-04-2012 |
20130046490 | TWO-WIRE PROCESS CONTROL LOOP CURRENT DIAGNOSTICS - A process variable transmitter controls a signal on a communication loop. A diagnostic component on the transmitter compares an expected signal level on the communication loop with an actual value to detect on-scale errors. | 02-21-2013 |
20130154862 | DYNAMICALLY ADJUSTED A/D RESOLUTION - A process variable transmitter is used to measure a process variable, and, in doing so, dynamically changes the resolution of the A/D converter based upon the measured value of the analog input signal. This can be done by automatically adjusting the configurable resolution gain adjustment based on the value of the analog signal being measured, by normalizing the input signal being measured so that it is centered in an optimal resolution window of the A/D converter, or by adjusting a voltage reference provided to the A/D converter. | 06-20-2013 |
20140088905 | PROCESS VARIABLE TRANSMITTER WITH EMF DETECTION AND CORRECTION - A preexisting voltage across a sensor is latched to a storage capacitor prior to any excitation current being applied to the sensor. Once the excitation current is applied, the voltage on the storage capacitor is directly subtracted from a differential voltage across the sensor. The subtraction is done before a measurement is converted to a digital value and passed to a transmitter. The subtraction is performed in hardware, and a time required to sample and hold the preexisting voltage across the storage capacitor is within a settling time used for collecting any sensor measurements. | 03-27-2014 |
20140241399 | PROCESS TEMPERATURE TRANSMITTER WITH IMPROVED SENSOR DIAGNOSTICS - A process temperature transmitter is operable with at least one temperature sensor having a plurality of leads. The temperature transmitter includes measurement circuitry operably coupleable to the at least one temperature sensor to provide an indication of an electrical parameter of the at least one temperature sensor. A controller is coupled to the measurement circuitry to obtain the indication and provide a process temperature output. A current source applies a test current to the plurality of leads simultaneously. Diagnostic circuitry measures a voltage response on each lead in order to provide a diagnostic indication of the temperature sensor. | 08-28-2014 |