Vega VEGABAR 82 Operating Instructions Manual

Also see for VEGABAR 82: Product information Operating instructions Quick setup guide Operating instructions Operating instructions

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619 SupplementVEGABAR 82 • Slave sensor for electronic differential pressure45050-EN-170522Ʋ with connected overvoltage protectionon the master sensorup to 5000 m (16404 ft)Pollution degree8) 4Protection rating (IEC 61010-1) IIApprovalsInstruments with approvals can have different technical specifications depending on the version.For that reason the associated approval documents of these instruments have to be carefullynoted. They are part of the delivery or can be downloaded under www.vega.com, "Instrumentsearch (serial number)" as well as in the download area.9.2 Calculation of the total deviationThe total deviation of a pressure transmitter indicates the maximum measurement error to be ex-pected in practice. It is also called maximum practical deviation or operational error.According to DIN 16086, the total deviation Ftotal is the sum of the basic accuracy Fperf and the long-term stability Fstab:Ftotal= Fperf + FstabThe basic accuracy Fperf consists of the thermal change of the zero signal and the output span FT aswell as the deviation FKl:Fperf = √((FT)2 + (FKl)2)The thermal change of zero signal and output span FT is specified in chapter "Technical data". Thebasic temperature error FT is shown in a graphic. Depending on the measuring cell version and Turndown, this value must be multiplied with the additional factors FMZ and FTD:FT x FMZ x FTDAlso these values are specified in chapter "Technical data".This applies for the digital signal output through HART, Profibus PA or Foundation Fieldbus.With a 4 … 20 mA output, the thermal change of the current output Fa must be added:Fperf = √((FT)2 + (FKl)2 + (Fa)2)To provide a better overview, the formula symbols are listed together below:• Ftotal: Total deviation• Fperf: Basic accuracy• Fstab: Long-term stability• FT: Thermal change of zero signal and output span (temperature error)• FKl: Deviation• Fa: Thermal change of the current output• FMZ: Additional factor measuring cell version• FTD: Additional factor Turn down9.3 Practical exampleDataLevel measurement in a small vessel, 500 mm height corresponds to 0.049 bar (4.9 KPa), superim-posed pressure 0.35 bar (35 KPa), medium temperature 40 °CVEGABAR 82 Master and slave sensor each with nominal measuring range 0.4 bar (40 KPa), devia-tion < 0.1 %, process fitting G1½ (measuring cell ø 28 mm)8) When used with fulfilled housing protection.