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Two Wire Pulse Output Transmitter

IP.com Disclosure Number: IPCOM000179833D
Original Publication Date: 2009-Mar-16
Included in the Prior Art Database: 2009-Mar-16
Document File: 2 page(s) / 104K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

At present, two-wire magnetic inductive flowmeters are known where power supply, analogue current output with 4-20mA, and HART (Highway Addressable Remote Transducer) communication are implemented using only a two-wire connection. The drawback of this solution is the limited power available for the transmitter, typically 4 to 200mW depending on analogue signal level. Other transmitters use an external power supply and a pulse output of typically 0-10Hz proportional to the measured value. These devices are, however, not intrinsically safe. Furthermore, they need more than two wire installation and they have no bus connection.

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Two Wire Pulse Output Transmitter

Idea: Steen Moellebjerg Matzen, DK-Nordborg

At present, two-wire magnetic inductive flowmeters are known where power supply, analogue current output with 4-20mA, and HART (Highway Addressable Remote Transducer) communication are implemented using only a two-wire connection. The drawback of this solution is the limited power available for the transmitter, typically 4 to 200mW depending on analogue signal level. Other transmitters use an external power supply and a pulse output of typically 0-10Hz proportional to the measured value. These devices are, however, not intrinsically safe. Furthermore, they need more than two wire installation and they have no bus connection.

The idea is to implement a two wire pulse output where the pulse output also delivers the power for the transmitter. The power level increases to typical 600mW independent of analogue signal level and is only limited by the requirements given from intrinsically safe systems. Furthermore, the power level for intrinsically safe systems named CIS (Continuous Interruption Supply) will be increased. Thus, a high performance of two wire intrinsically safe systems can be achieved. Moreover, the total system cost can be lowered.

An implementation example is shown in Figure 1. The system consists of an analogue frontend that converts the input from the sen...