Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: Systems and techniques for accessing and controlling field devices to collect data and convert protocols are disclosed herein. An example system to access a field device includes one or more processors, a transmitter, a wireless network interface controller, and a memory storing instructions that, when executed, may cause the field communicator device to retrieve process parameter data encoded in a field device transmission protocol. The field communicator device may retrieve the process parameter data at a plurality of time intervals from a field device, and the process parameter data may correspond to a process parameter for the field device. The field communicator device may also store at least some of the process parameter data, analyze the process parameter data over the plurality of time intervals to identify a condition of the field device, and transmit an indication of the condition of the field device to a remote device.

Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: An example apparatus includes a first sensor tag to retrieve operational data, via a modem and a data bus, from a process control field device, wherein the first sensor tag includes a memory to store the operational data; a first antenna arranged to communicate with the first sensor tag when the first sensor tag receives operational data, the first antenna to communicate with the first sensor tag via a first frequency band; and a first identification device to retrieve the operational data from the first sensor tag, via the first antenna and the first frequency band, while the process control field device is unpowered.

Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: Systems and techniques for accessing and controlling field devices to collect data and convert protocols are disclosed herein. An example system to access a field device includes one or more processors, a transmitter, a wireless network interface controller, and a memory storing instructions that, when executed, may cause the field communicator device to retrieve process parameter data encoded in a field device transmission protocol. The field communicator device may retrieve the process parameter data at a plurality of time intervals from a field device, and the process parameter data may correspond to a process parameter for the field device. The field communicator device may also store at least some of the process parameter data, analyze the process parameter data over the plurality of time intervals to identify a condition of the field device, and transmit an indication of the condition of the field device to a remote device.

Abstract: A control loop for a double-acting pneumatic actuator is configured to generate two control signals, one for each of the two pneumatic chambers for the purpose of controlling the actuator position in view of operating constraints on the chamber pressures or the stiffness of the actuator. A numerical indicator of the stiffness may be computed in a variety of ways, for example, as the average of the two chamber pressures. In one embodiment a numerical indicator of stiffness is treated as an output of the system along with the position of the actuator. A multi-input multi-output control loop with position and pressure feedback may be used to simultaneously control the position and the stiffness of the actuator.

Abstract: Methods and apparatus for RFID communications in a process control system are disclosed. An example apparatus includes a non-volatile memory to be operatively coupled to a field device of a process control system; and a radio-frequency identification tag to be operatively coupled to the non-volatile memory. The non-volatile memory is to store data received from at least one of the field device or a radio-frequency identification writer via the radio-frequency identification tag. The radio-frequency identification tag is to wirelessly transmit the data to a radio-frequency identification reader. The data includes at least one of maintenance information, diagnostic information, or configuration information associated with the field device. The non-volatile memory and the radio-frequency identification tag to be physically coupled to the field device.

Abstract: A valve body has in inlet, an outlet, and a port positioned between the inlet and outlet. An approach passage interconnects the inlet and the port and has a cross-sectional area that is greater than that of the port. One or more guide vanes are positioned within the approach passage and extend longitudinally along at least a portion of the approach passage so that a downstream end of the guide vanes is spaced apart from the port and the guide vanes divide the portion of the approach passage into sub-passages that have equal flow resistances.

Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: To generate a setpoint signal to stroke a valve during a partial-stroke test, a first target is determined for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test; the setpoint signal is ramped from an initial value to the first target, during a first time interval; subsequently to the first time interval, the setpoint signal is maintained at the first target during a second time interval; a second target is determined for the setpoint signal based at least on the initial value; and during a third time interval subsequent to the second interval, the setpoint signal is ramped from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval.

Abstract: Methods and apparatus for RFID communications in a process control system are disclosed. An example apparatus includes a non-volatile memory to be operatively coupled to a field device of a process control system; and a radio-frequency identification tag to be operatively coupled to the non-volatile memory. The non-volatile memory is to store data received from at least one of the field device or a radio-frequency identification writer via the radio-frequency identification tag. The radio-frequency identification tag is to wirelessly transmit the data to a radio-frequency identification reader. The data includes at least one of maintenance information, diagnostic information, or configuration information associated with the field device. The non-volatile memory and the radio-frequency identification tag to be physically coupled to the field device.

Abstract: The present invention includes a method, apparatus, and computer readable medium for controlling a valve. Example embodiments of the present invention described herein utilize a soft cutoff threshold and soft cutoff procedure at which point the controller monotonically ramps a servo set-point to slowly overdrive the servo beyond a calibrated set-point range, wherein the servo transitions into a hard cutoff when the servo set-point reaches a predefined overdrive threshold.

Abstract: An example apparatus includes a first sensor tag to retrieve operational data, via a modem and a data bus, from a process control field device, wherein the first sensor tag includes a memory to store the operational data; a first antenna arranged to communicate with the first sensor tag when the first sensor tag receives operational data, the first antenna to communicate with the first sensor tag via a first frequency band; and a first identification device to retrieve the operational data from the first sensor tag, via the first antenna and the first frequency band, while the process control field device is unpowered.

Abstract: Methods and apparatus for RFID communications in a process control system are disclosed. An example apparatus includes a radio-frequency identification (RFID) device to be communicatively coupled to a field device of a process control system via a wired connection. The RFID device includes an RFID tag to be powered via the wired connection based on power provided to the field device. The power is provided to the field device along with a control signal.

Abstract: A method of calibrating a positioner includes determining a pressure value corresponding to a particular state of an actuator, wherein the actuator is controlled by the positioner, and controlling a pressure within the actuator according to a set point pressure, wherein the set point pressure is based on the pressure value such that the particular state of the actuator is maintained. The method further includes receiving a measured value indicating an actual pressure within the actuator, and determining a bias of the positioner based on the measured value and the set point pressure.

Abstract: Methods and apparatus for multimode RFST communications in process control systems is disclosed herein. A disclosed example apparatus includes an example RFST module associated with a process control device of a process control system. The example RFST module includes a plurality of RFSTs configured to communicate by different communication protocols. The example RFST module also includes a power module to power the RFST module to enable communications with a processor or memory associated with the process control device.

Abstract: A control loop for a double-acting pneumatic actuator is configured to generate two control signals, one for each of the two pneumatic chambers for the purpose of controlling the actuator position in view of operating constraints on the chamber pressures or the stiffness of the actuator. A numerical indicator of the stiffness may be computed in a variety of ways, for example, as the average of the two chamber pressures. In one embodiment a numerical indicator of stiffness is treated as an output of the system along with the position of the actuator. A multi-input multi-output control loop with position and pressure feedback may be used to simultaneously control the position and the stiffness of the actuator.

Abstract: A valve body has in inlet, an outlet, and a port positioned between the inlet and outlet. An approach passage interconnects the inlet and the port and has a cross-sectional area that is greater than that of the port. One or more guide vanes are positioned within the approach passage and extend longitudinally along at least a portion of the approach passage so that a downstream end of the guide vanes is spaced apart from the port and the guide vanes divide the portion of the approach passage into sub-passages that have equal flow resistances.