A field device includes a detected signal converter configured to convert a detected signal of a sensor into a predetermined voltage and then to output the voltage, an amplifier configured to amplify an output signal of the detected signal converter, and a switching power supply as an internal driving power supply of the field device.

A sensor system having a current interface includes a supply and current interface, an electronic control unit and an enhanced initialization sensor. The supply and current interface is configured to receive a supply voltage. The electronic control unit is coupled to the supply and current interface. The enhanced initialization sensor is coupled to the supply and current interface. The enhanced initialization sensor is configured to initialize the supply and current interface at a suitable current level to mitigate erroneous information. measurement system.

A sensor system having a current interface includes a supply and current interface, an electronic control unit and an enhanced initialization sensor. The supply and current interface is configured to receive a supply voltage. The electronic control unit is coupled to the supply and current interface. The enhanced initialization sensor is coupled to the supply and current interface. The enhanced initialization sensor is configured to initialize the supply and current interface at a suitable current level to mitigate erroneous information. measurement system.

Some embodiments are directed to a process device comprising a process variable sensor configured to generate an output signal indicative of a sensed process variable; loop current output circuitry configured to control a loop current on a two wire process control loop to a value based on the output signal; loop current measurement circuitry coupled to the process control loop and configured to generate a measured loop current value based on the loop current; and loop current verification circuitry configured to approximate the loop current value based on the output signal and properties of a low pass filter, and generate a diagnostic signal based on a comparison of the approximated loop current value and the measured loop current value.

Some embodiments are directed to a process device comprising a process variable sensor configured to generate an output signal indicative of a sensed process variable; loop current output circuitry configured to control a loop current on a two wire process control loop to a value based on the output signal; loop current measurement circuitry coupled to the process control loop and configured to generate a measured loop current value based on the loop current; and loop current verification circuitry configured to approximate the loop current value based on the output signal and properties of a low pass filter, and generate a diagnostic signal based on a comparison of the approximated loop current value and the measured loop current value.

A sensor system having a current interface includes a supply and current interface, an electronic control unit and an enhanced initialization sensor. The supply and current interface is configured to receive a supply voltage. The electronic control unit is coupled to the supply and current interface. The enhanced initialization sensor is coupled to the supply and current interface. The enhanced initialization sensor is configured to initialize the supply and current interface at a suitable current level to mitigate erroneous information.

A sensor system having a current interface includes a supply and current interface, an electronic control unit and an enhanced initialization sensor. The supply and current interface is configured to receive a supply voltage. The electronic control unit is coupled to the supply and current interface. The enhanced initialization sensor is coupled to the supply and current interface. The enhanced initialization sensor is configured to initialize the supply and current interface at a suitable current level to mitigate erroneous information.

A system for coupling a modulated voltage signal onto a current loop between a host device and a field device, in various embodiments, can include a circuit and an impedance bridge. The circuit is configured to flow current from the field device between two terminals of an input circuit in the host device, wherein the two terminals are included in the current loop. The impedance bridge is positioned between the two terminals and configured to modulate impedance to convert the current in a field loop produced by the field device into terminal voltage modulation, without introducing a DC voltage burden to the current.

A system for coupling a modulated voltage signal onto a current loop between a host device and a field device, in various embodiments, can include a circuit and an impedance bridge. The circuit is configured to flow current from the field device between two terminals of an input circuit in the host device, wherein the two terminals are included in the current loop. The impedance bridge is positioned between the two terminals and configured to modulate impedance to convert the current in a field loop produced by the field device into terminal voltage modulation, without introducing a DC voltage burden to the current.

A circuit system includes: a receiver circuit which outputs a periodic voltage pulse via a bus line; and an ascertaining device configured to ascertain whether the voltage on the bus line has reached a specified threshold value. The circuit system is configured to start the reception of data signals a specified time period after an instant at which the voltage on the bus line has reached the specified threshold value.