Application note Level (closed vessel) SITRANS P DSIII. Unrestricted

Transcription

1 Application note Level (closed vessel) SITRANS P DSIII Unrestricted

2 Agenda 1 Calculation of hydrostatic level Adjustment level application (Steps to do) 2 Comissioning of a level application "closed vessel" (Steps to do) 5 3 Trouble shooting of a level application "closed vessel" (Steps to do) 9 Page 2

3 Calculation of hydrostatic level Application closed vessel Vessel Distance between measuring points H max = 1,56m Pressure water column: p Hmax = 153 mbar Calculation: Product: Water [ρ = ] Local acceleration due to gravity [g = 9,81 ] p Hmax = ρ * g * h p Hmax = * g * 9,81 * 1,56m p Hmax = = 153 mbar Page 3

4 Adjustment level application Closed vessel Steps to do: 1. Empty the tank [Fill vessel to min level] 2. Mode 7: Press [, ] simultaneously for 2 s 3. Mode 2: Press [, ] simultaneously for 2 s 4. Fill the vessel to the max level 5. Mode 3: Press [, ] simultaneously for 2 s Page 4

5 Agenda 1 Calculation of hydrostatic level 2 2 Comissioning of a level application "closed vessel" (Steps to do) Detailed explanation of level application adjustment 3 Trouble shooting of a level application "closed vessel" (Steps to do) 9 Page 5

6 What happens during the adjustment? Explanation: SITRANS P DSIII 250mbar measuring span Factory adjustment [no Y01 option (special measuring range set in factory)] Transmitter and remote seal same horizontal level 0mbar = 4mA; 250mbar = 20mA Transmitter installed Due to the oil column of the capillaries [H v ] the measured pressure is around -150mbar. Current output 3.84mA. Page 6

7 What happens during the adjustment? Explanation: SITRANS P DSIII 250mbar measuring span Mode 7: Press [, ] simultaneously for 2 s Span shifted by Mode 7, Mode 2: Press [, ] simultaneously for 2 s Mode 3: Press [, ] simultaneously for 2 s Upper range value set Page 7

8 Adjustment level application Print version Factory adjustment [no Y01 (special measuring range)] Transmitter and remote seal same horizontal level Transmitter installed Hydrostatic pressure due to oil column of the capillaries Vessel min. level Mode 7: Press [, ] simultaneously for 2 s Mode 2: Press [, ] simultaneously for 2 s Span shifted by Mode 7 Vessel max. level Mode 3: Press [, ] simultaneously for 2 s Upper range value set Page 8

9 Agenda 1 Calculation of hydrostatic level 2 2 Comissioning of a level application "closed vessel" (Steps to do) 5 3 Trouble shooting of a level application "closed vessel" (Steps to do) Detailed explanation of the trouble shooting Page 9

10 Troubleshooting Level application closed vessel Problem: Someone has changed the settings. 4 20mA signal does not comply to the level Steps to do: 1. The distance between min and max must be measured (Value = H max ). This level complies to 20mA 2. The measuring span must be calculated (p = ρ * g * H max ) and compared to the values in Mode 5 and 6 Mode 5 = 0; Mode 6 = p Hmax 3. The actual level must be measured (Value = H actual ). 4. Calculate the percentage and the pressure value that corresponds. 5. Mode 7 adjust the calculated pressure value. Page 10

11 Troubleshooting: Level application closed vessel Offset error, Level can not be changed Application was working properly. Someone changed zero point setting. Example: 1. H max Measure: H max = 1,56m Calculate: p Hmax = 153mbar 2. Compare: Mode 5 = 0; Mode 6 = p Hmax = 153mbar Values are all right; Problem: zero point adjustment wrong! 3. H actual Measure: H actual = 0,936m, % 4. Calculate Percent:, =, ; % = % %, p Hactual = p Hmax * factor =153mbar * 0,6 = 91,8 mbar = 60%; factor = 0,6 5. Mode 7: use the arrow [ or ] to adjust the value to 91,8 mbar on the display. Press Mode [M]; Job done! Page 11

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