Teledyne NALL instruction manual Electrical Zero Check

Page 10

4.4.3Electrical Zero Check

Turn the power supply “ON” and allow the flowmeter 30 minutes to warm up. Stop all flow through the transducer and check the electrical zero.

CAUTION: DO NOT ASSUME THAT ALL METERING VALVES WILL COMPLETELY SHUT OFF FLOW. EVEN A SLIGHT LEAKAGE THROUGH A VALVE WILL CAUSE AN INDICATION ON THE METER WHICH WILL FALSELY APPEAR TO BE A ZERO SHIFT.

If necessary, adjust the “ZERO” potentiometer located on the front panel of the power supply, until the meter indicates zero.

Manual 111-082010_Nall Mass Flowmeters

Page 10 of 23

Image 10

Contents Teledyne Hastings Manual Print History Table of Contents 12.0 Features General InformationOperating Principle Operating Principle Receiving and Inspection Installation Instructions TransducerFilters Power SupplyCables Electrical Zero Check Using the Flowmeter Flowmeter Factory Calibrated for a Special Gas Output SignalGas Mixtures Repeatability AccuracyOver-range Low Pressure Drop Transducers Pressure EffectsStandard Transducers High Pressure Transducers OptionalPower Supply Temperature EffectsAmbient Temperatures Transducer Gas TemperatureChanges in DP with Changes in Line Pressure Differential PressureTypical Pressure Drops Increase in Line PressureDecrease in Line Pressure DP Increase Due to Fouling of the TransducerCalibration Procedures CalibrationTransducer Power Supply Troubleshooting MaintenanceTransducers Cleaning Damage to the TransducerDouble Point Relay Flowmeter/Alarm DNALL-P AccessoriesOptions and Accessories Totalizers TNALL-P DescriptionsChassis Model NALL-C MaintenanceCurrent Converter NAll-P/CC Warranty Repair Policy Warranty and RepairNon-Warranty Repair Policy