Measuring arrangement with a control unit and method for operating such a measuring arrangement

Patent metadata

Field	Value
Publication number	US-10962998-B2
Application number	US-201816016276-A
Country	US
Kind code	B2
Filing date	Jun 22, 2018
Priority date	Sep 21, 2017
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A measuring arrangement with a control unit, an energy supply unit for a plurality of two-line field devices, which apply a predetermined current upon a measuring loop in which the two-line field devices are respectively arranged, with the two-line field devices being electrically connected to the energy supply unit and communicating digitally with the control unit, with the energy supply unit comprising a voltage controller, which controls an output voltage depending on the number the means of the measuring arrangement for determining a number of two-line field devices operated in the measuring arrangement.

First claim

We claim:

1. A measuring arrangement comprising a control unit, an energy supply unit for a plurality of two-line field devices, which apply a predetermined current upon a measuring loop in which the two-line field devices are respectively arranged, with the two-line field devices being electrically connected parallel to the energy supply unit and digitally communicate with the control unit, wherein the energy supply unit comprises a voltage controller and the measuring arrangement comprises means for determining a number of two-line field devices operated in the measuring arrangement, and controls the output voltage as a function of the number.

2. The measuring arrangement according to claim 1 , wherein the energy supply unit is integrated in the control unit or a modem connected thereto.

3. The measuring arrangement according to claim 1 , wherein the energy supply unit is embodied as a separate feeding device.

4. The measuring arrangement according to claim 1 , wherein a communication resistor is arranged between the energy supply unit and the two-line field devices, via which a signal modulated on the measuring loop is converted into a voltage that can be detected by the modem and a voltage applied by the modem can be converted into a corresponding current.

5. The measuring arrangement according to claim 1 , wherein the output voltage is controlled such that sufficient minimum voltage is applied to each measuring unit.

6. The measuring arrangement according to claim 1 , wherein the output voltage is controlled depending on a total current required by the field devices.

7. The measuring arrangement according to claim 1 , characterized in that the number of connected field devices can be adjusted.

8. The measuring arrangement according to claim 1 , wherein the control unit is battery operated.

9. The measuring arrangement according to claim 1 , wherein the control unit and the field devices communicate pursuant to the HART-multidrop protocol with frequency shift keying.

10. A method for operating a measuring arrangement comprising a control unit, an energy supply unit for a plurality of two-line field devices, which apply a predetermined current to a measuring circuit in which the two-line field device are respectively arranged, with the two-line field devices being connected electrically parallel to the energy supply unit and digitally communicate with the control unit, characterized in that an output voltage of the energy supply unit is controlled depending on the number of field devices connected to the energy supply.

11. The method according to claim 10 , wherein the measuring arrangement initially adjusts the maximum output voltage, determines a number of field devices located in the measuring arrangement by measuring the current, and then the output voltage is set to an adjusted value.

12. The method according to claim 10 , wherein a required output voltage is determined via an inquiry of the necessary minimum voltage of the field devices connected and then the output voltage is adjusted such that at the field devices the highest minimum voltage is applied.

13. The method according to claim 10 , wherein the number of connected field devices and the minimum voltage are cyclically checked and the output voltage is adjusted.

Assignees

• Vega Grieshaber Kg Wolfach
• Grieshaber Vega Kg

Inventors

• Mueller Tobias
• Staiger Holger

Classifications

• H04B3/548 Primary

  the power on the line being DC (arrangements for feeding power H04L12/10; extracting feeding power from signals H04L25/02) · CPC title

• G05B19/0428

  Safety, monitoring (G05B19/0423 takes precedence) · CPC title

• H04L67/12

  specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks · CPC title

• G05B21/02

  electric · CPC title

• G05F1/625 Primary

  wherein it is irrelevant whether the variable actually regulated is AC or DC · CPC title