摘要:
Field devices are commonly used in unprotected environments, which means that these field devices and the conductor pairs connecting the field devices to the input modules/output modules of an automation installation are exposed to significant climatic and environmental factors. These factors have a detrimental effect on the transmission quality of the signals to be transferred between field devices and modules, which may result in erroneous measurements and dangerous operating states during control of a technical process. Measures to simplify monitoring of the transmission medium are proposed.
摘要:
The invention relates to a method for monitoring an output driver that can be parameterized and is suitable for controlling actuators in industrial automation technology, for applying analog signals to an output channel, with the following steps: determining resulting internal leakage power based on the parameterization data provided for parameterizing the output driver, comparing the leakage power relative to a leakage power limiting value, and, dependent functionally on the comparison result, stopping the application of an analog signal on the output channel corresponding to the parameterization data provided for parameterizing the output driver. The invention further relates to an analog signal output device, suitable for controlling actuators in industrial automation technology and in accordance with the aforementioned method, comprising at least one output driver and a monitoring device.
摘要:
Conversion circuitry for use in a process control system is adapted for coupling to a primary process control loop. Digital receiver circuitry in the conversion circuitry receives a digital signal transmitted over the primary process control loop from a field transmitter and responsively provides a digital output. A microprocessor receives the digital output and responsively provides a secondary loop control output. Secondary loop control circuitry for coupling to a secondary process control loop receives the secondary loop control output from the microprocessor and responsively controls current flowing through the secondary process control loop. The current flowing through the secondary process control loop is related to the digital signal transmitted by the field transmitter.
摘要:
A protective circuit for a process control device such as a valve actuator, for example, prevents damage to device components. In particular, a protective circuit allows an analog current loop (e.g., 4-20 mA) to provide to a device component a secondary operating voltage, derived from the analog current loop, in the absence of a primary operating voltage source (e.g., during a power failure), such that the device component is not damaged when a signal from the analog current loop is applied to the process control device in the absence of the primary operating voltage source.
摘要:
Control electronics (E) for a two-wire process device, which two-wire process device can be connected to a two-wire loop (2L), wherein the control electronics (E) comprises an input circuit (ES) and a control unit connected to the input circuit (ES), wherein the input circuit (ES) is used in a first operating mode to set a current and/or voltage in the two-wire loop (2L) by means of a control signal (CS) transmitted by the control unit (SE), wherein the input circuit (ES) is used in a second operating mode to automatically, in particular independently of the control unit (SE) or independently of the control signal (CS) transmitted by the control unit (SE), to set the current and/or the electric voltage in the two-wire loop (2L).
摘要:
Field devices are commonly used in unprotected environments, which means that these field devices and the conductor pairs connecting the field devices to the input modules/output modules of an automation installation are exposed to significant climatic and environmental factors. These factors have a detrimental effect on the transmission quality of the signals to be transferred between field devices and modules, which may result in erroneous measurements and dangerous operating states during control of a technical process. Measures to simplify monitoring of the transmission medium are proposed.
摘要:
A wireless adapter for use with a two-wire process control loop is configured to couple to a process field device in an industrial process control system. The wireless adapter is coupled to the two-wire process control loop and provides wireless communication to the process field device. The adapter includes first and second loop terminals configured to couple in series with the two-wire process control loop. Wireless communication circuitry is coupled to the first and second loop terminals and is adapted to provide wireless communication to the process field device. Loop current bypass circuitry is electrically connected between the first and second loop terminals and is configured to provide a loop current path therebetween in response to an open circuit in wireless communication circuitry.
摘要:
A current generator that provides a first current level to read a configuration parameter of a field device. The current generator also provides a second current level. The first current level is lower in amperage than the second current level. The first current level does not operate the field device. The second current level operates the field device. A current sensor is connected in circuit with the field device. The current sensor reads the configuration parameter associated with the first current level. A method is provided that creates a current that reads a configuration parameter. The current has less than a minimum amplitude to operate necessary to operate a field device. The configuration parameter is read from the field device through employment of the current. The field device is configured through employment of the configuration parameter.
摘要:
A current generator that provides a first current level to read a configuration parameter of a field device. The current generator also provides a second current level. The first current level is lower in amperage than the second current level. The first current level does not operate the field device. The second current level operates the field device. A current sensor is connected in circuit with the field device. The current sensor reads the configuration parameter associated with the first current level. A method is provided that creates a current that reads a configuration parameter. The current has less than a minimum amplitude to operate necessary to operate a field device. The configuration parameter is read from the field device through employment of the current. The field device is configured through employment of the configuration parameter.
摘要:
Conversion circuitry for use in a process control system is adapted for coupling to a primary process control loop. Digital receiver circuitry in the conversion circuitry receives a digital signal transmitted over the primary process control loop from a field transmitter and responsively provides a digital output. A microprocessor receives the digital output and responsively provides a secondary loop control output. Secondary loop control circuitry for coupling to a secondary process control loop receives the secondary loop control output from the microprocessor and responsively controls current flowing through the secondary process control loop. The current flowing through the secondary process control loop is related to the digital signal transmitted by the field transmitter.