Servo Based Tank gauging 139 M

The 139M Servo Gauge is an intelligent, microprocessor based instrument for accurate measurement of product level, interface level, density & temperature. It is used for custody transfer & inventory control applications & meet the requirements according to OIML R85 & is SIL2 certified (Functional Safety) for overfill protection applications in hazardous locations.
  • SIL2 Certified.
  • Level, Interface Level and Density Measurement in one instrument.
  • Average temperature measurement with external temperature sensor.
  • On demand spot/average density and real time average density (using pressure transmitter) options.
  • Two wire transmission bus allows looping, reduces cabling.
  • Automatic calibration of product level and compensation for density variations.
  • Automatic compensation for wire weight and tank deformation.
  • Wave integration in level measurement.
  • Local and remote repeatability check.
  • Field calibration and checking through portable programming unit possible without opening the instrument.
  • Weights and Measures approval as per OIML-R85 standard
Level & Interface level measurement
Measuring Range 0-27000 mm (standard)
0-37000 mm (on request)
Level Accuracy +/- 0.6 mm*
Sensitivity +/- 0.1 mm*
Repeatability +/- 0.1 mm*
Interface Accuracy +/- 2 mm*
Resolution 1 mm or 0.1 mm (selectable)
Displacer Speed 2400 mm / minute (maximum)
Displacer diameter 90 mm (standard)
45 mm and 65 mm (optional)
Density measurement accuracy  
On demand +/- 0.005 gm/cc
Real time +/- 0.08 %
With a pressure transmitter of accuracy ± 0.04% of
URL. Accuracy of real time density measurement is a
function of the accuracy of pressure transmitter.
Temperature Measurement Using external temperature sensor
Measuring Range -200°C to +200°C
Accuracy + /- 0.2°C
Resolution 0.1°C
Sensor type RTD spot / Multi Point averaging (Max. 14 points)
LPG mass measurement  
Accuracy +/- 1.3% of reading with SG density
+/- 0.3% of reading with manually entered density
Resolution 0.01 MT
Protection Flameproof to IS/IEC 60079-1:2007, Zone 1, Gr. IIA & IIB
Weatherproof IP65 as per IS/IEC 
Terminals for temperature sensor Intrinsically safe to IS/IEC 60079-11:xxxx, Ex ia IIA and  IIB T6
Operating Temperature -10°C to +60°C
Power Supply 110/230 Vac, +/- 10%, 50 Hz, 1 phase, mains isolated, 25 VA
SIL2 outputs 4-20 mA output proportional to level and/or
2 nos. Alarm Relay Contacts.
  • Bulk Storage tanks in Refineries, Petroleum Storage Terminals / Depot, Chemicals and Petrochemicals.
  • LPG storage tanks.
  • Servo Gauge based Tank Farm Management System.