ABB 6X1EH Operating Instructions Manual

Also see for 622ED: Instructions

Contents

ABB 6X1EH Operating Instructions Manual Manual pdf 5 page image

- 5 -The instrument consists of two functional units:- Primary Unit- Secondary UnitThe Primary Unit includes the process interface and thesensor, the Secondary Unit includes the electronics, the terminalblock and the housing. The two units are mechanically coupledby a threaded joint. The Electronics of Secondary Unit is basedon custom integrated components (Application SpecificIntegrated Circuit - ASIC).Resin pottingPrimary ElectronicsPrinted CircuitSensor Diaphragmwith Ferrite DisksProcesschamberCapillary tubingInductance Coils& MagneticCoresIsolatingdiaphragmFig. 2a - Primary UnitPRINCIPLE OF OPERATIONThe principle of operation of the Primary Unit is as follows. Theprocess fluid ( liquid, gas or vapour ) exerts pressure on to thesensor diaphragm via flexible, corrosion-resistant isolatingdiaphragms and capillary tubing containing the fill fluid (seeFig. 2a).As the sensor diaphragm deflects in response to differentialpressure changes, it simultaneously produces variations in thegap between two fixed magnetic circuits (comprising coil andferrite core) positioned on both sides of the measuringdiaphragm. As a result, the inductance of each coil changes.The two inductance values L1 and L2, and the sensortemperature ST are combined in the primary electronics toprovide a proprietary standardized signal.In the manufacturing process the sensor output characteristicsare compared with reference pressures and temperatures: the"mapped" parameters are then stored in the memory of Primaryelectronics.The measured values and the sensor parameters are transferredto the Secondary Unit, where a microprocessor computesprecise primary output linearisation, compensating for thecombined effects of sensor non linearity, of static pressure andtemperature changes. In the secondary electronics permanentmemory are stored the transmitter specific information:- non modifiable data such as the serial number, the UID(Unique Identifier), the manufacturer's name and device type,the hardware and software version of the electronics.- the modifiable data such as the final trimming and calibration,in other words, all data that can be changed by the userthrough the configuration devices.External Zero/SpanadjustmentsFig. 2b - Secondary UnitOutput meter(option)Surge protector(option)TerminalblockHousing ElectronicsIntegral meter(option)RFI filterCapillary tubingProcesschamberIsolatingdiaphragm