NMT - Kobold

Operating InstructionsforMagnetostrictive Level MeterModel: NMT

NMT1. Contents1. Contents ............................................................................. 22. Note.................................................................................... 33. Instrument Inspection ......................................................... 34. Regulation Use ................................................................... 35. Operation Principle ............................................................. 46. Mechanical connection ....................................................... 47. Electrical connection........................................................... 48. Commissioning ................................................................... 59. Maintenance....................................................................... 510. Technical Data.................................................................... 511. Order Codes ....................................................................... 612. Dimensions......................................................................... 613. Declaration of Conformance............................................... 7Manufactured and sold by:Kobold Messring GmbHNordring 22-24D-65719 HofheimTel.: +49(0)6192-2990Fax: +49(0)6192-23398E-Mail: info.de@kobold.comInternet: www.kobold.comSeite 2 NMT 12/04

NMT2. NotePlease read and take note of these operating instructions before unpacking andsetting the unit for operation, and follow the instructions precisely as describedherein.The devices are only to be used, maintained and serviced by persons familiarwith these operating instructions and with the prevailing regulation applying toprocedural safety and the prevention of accidents.3. Instrument InspectionThese devices are checked before dispatch and sent away in perfect condition.Should the damage to a device be visible, we recommend a thorough inspectionof the delivery packing. In case of damage, please inform your parcel service/forwarding agent immediately, since they are responsible for damages duringtransit.Scope of delivery:• Magnetostrictive Level Meter, Model NMT• Operating Instructions4. Regulation UseThe level meter is to be installed only in the specified applications. Every usagewhich exceeds the specifications is considered to be non-specified. Anydamages resulting therefrom are not the responsibility of the manufacturer. Theuser assumes all risk for such usage. The application specifications include theinstallation, start-up and service requirements specified by the manufacturer.NMT 12/04 Seite 3

NMT5. Operation PrincipleThe Kobold level meter NMT is a very accurate float-controlled sensor for thecontinuous measurement of levels.The principle of measurement is based on echo time measurement. A magnetostrictivewire is tensioned in the guide tube. Current pulses are transmittedthrough the wire thus generating an annular magnetic field around the wire. Thewire is also magnetized axially by magnets fitted in the float. Due to the superimpositionof both magnetic fields, a torsional impulse is generated in the vicinity ofthe float magnet, which propagates with ultrasonic speed in both directions. Thedistance from the float magnet to a defined zero-point is measured by an echotime measurement. The integrated electronics transforms the signal to a standardizedanalog signal.6. Mechanical ConnectionMount the level meter with guide tube on the vessel.Use suitable flat gasket for screwing.7. Electrical InspectionConnect level meter according to the following wiring diagram:GND+UsAGNDAOUT24 V DC4-20mA-+-+Terminal assignmentsGND: 0 V supply+U S : 24 V DC supplyAGND: analog output GNDAOUT: analog output 4-20 mASeite 4 NMT 12/04

NMT8. CommissioningThe magnetostrictive level meter is ready for operation after mechanical andelectrical connection.9. MaintenanceThe instrument needs no maintenance when the measured medium is notpolluted.Remove any dirt from guide tube and float with a suitable cleaning agent.To dismantle the float, undo the retaining washer with the flat-head screw.By installation after cleaning, secure the flat-head screw with a screw-lock fluid toprevent loosening.10. Technical DataAccuracy:± 1 mmMeasuring length:300...2500 mmLength of guide tube: measuring length + 114 mmOverall length:see DimensionsStandard density: 1.0 g/cm 3Special density: 0.7 g/cm 3Max. service temperature: 80 °CMax. operating pressure: PN 10Connection / guide tube: stainless steel 1.4571Float: stainless steel 1.4701Connection box:aluminiumProcess connection:G 2 male or 2 NPTElectrical connection: terminal block in connection boxAnalog output:4...20 mA 4-wireLoad:500 ohmPower supply: 24 V DC ± 20%Power consumption:< 4 WProtection model: IP 65NMT 12/04 Seite 5

NMT11. Order CodesDescription Model ConnectionTransducerMeasuring tube st. steelConnection G 2 AGDensity 1.0 kg/dm 3TransducerMeasuring tube st. steelConnection 4 – 20 mADensity 0.8 kg/dm 3NMT-1201NMT-1208R50 = G2N20 = 2 NPT12. DimensionsSeite 6 NMT 12/04

NMT13. Declaration of ConformanceWe, KOBOLD-Messring GmbH, Hofheim-Ts, Germany, declare under our soleresponsibility that the product:magnetostrictive level metermodel: NMTto which this declaration relates is in conformity with the standards noted below:EN 50082-2 1996-02Electromagnetic compatibility basic specification noise immunityDIN EN 61000-4-2 1996-03Noise immunity to electrostatic discharge (e.s.d.)DIN EN 61000-4-4 1996-03Noise immunity to fast transients (BURST)DIN EN 61010-1 1994-03Safety requirements for electrical measuring, control and laboratory instrumentsEN 60529, DIN VDE 0470-1 1992-11Protection type through case (IP code)Also the following EWG guideline is fulfilled:89/336/EWGElectromagnetic compatibilitySigned: Date: 22.06.01H. Peters M. WenzelNMT 12/04 Seite 7