LTconfig is an offline, mobile-first field tool for instrument technicians, commissioning engineers, and operators — convert between %span, mA, and height of liquid in a horizontal vessel. Calculate horizontal vessel (tank) volume and set the 4–20 mA level transmitter scaling (LRV, URV, measuring span) for any 4–20 mA transmitter — differential pressure (DP), displacer, capacitance, or guided wave radar (GWR). For GWR on a bridle or chamber it goes further: from your nozzle elevations, flange face, and probe length it derives the null (blanking) zones, the AMS tank height, and the LRV/URV span. It runs entirely in your browser and works with no signal in the field.
Jump to: vessel volume · transmitter span · GWR bridle · FAQ
The partial volume of a horizontal cylinder is the circular-segment area at the liquid level times the shell length, plus the volume of the two heads (2:1 ellipsoidal, hemispherical, or ASME 80:10 F&D torispherical; flat heads add no volume). Segment area: A = R²·acos((R−h)/R) − (R−h)·√(2Rh−h²), where R is the inside radius and h the level. Worked example: 60″ ID × 20 ft shell, 2:1 ellipsoidal heads, liquid at 36″ → ≈ 1,999 gal (47.6 bbl). Output in gallons or barrels.
LRV is the level at 4 mA (0%); URV the level at 20 mA (100%); the measuring span is URV − LRV. These apply to any 4–20 mA level transmitter — differential pressure (DP), displacer, capacitance, or guided wave radar. The loop current is mA = 4 + 16·(level − LRV) / (URV − LRV). Worked example: LRV 10″, URV 90″, level 50″ → 12 mA (50% of span). Handles suppressed and elevated zero, and builds a setpoint table (sometimes called a strapping table) of level and mA at each alarm setpoint.
Enter the upper and lower process nozzle elevations, the flange face (upper reference), and your probe length; LTconfig derives the upper and lower null (blanking) zones and the AMS tank height, and sets LRV at the lower nozzle and URV at the upper nozzle (clamped to the vessel) for the measuring span. Worked example: lower nozzle 12″, upper nozzle 84″, flange face 88″, probe length 79″ → upper null 4″, lower null 3″, LRV 12″, URV 84″, span 72″.
How do you calculate the volume of a horizontal vessel?
A horizontal cylinder’s partial volume is the circular-segment area at the liquid level times the shell length, plus the volume of the two heads (2:1 ellipsoidal, hemispherical, or ASME 80:10 F&D torispherical; flat heads add no volume). The segment area is A = R²·acos((R−h)/R) − (R−h)·√(2Rh−h²). LTconfig computes it from the inside diameter, shell length, head type, and level.
How do you set LRV and URV for a level transmitter?
LRV is the level at 4 mA (0%) and URV is the level at 20 mA (100%); the measuring span is URV minus LRV. The loop current is mA = 4 + 16·(level − LRV) / (URV − LRV). Enter the range and LTconfig returns the span and the expected mA at any level. These are the range values you set during transmitter calibration or ranging; LTconfig computes the numbers to enter, not the as-found/as-left calibration record.
How do you configure guided wave radar (GWR) on a bridle?
Enter the upper and lower nozzle elevations, the flange face (upper reference), and your probe length. LTconfig derives the upper and lower null (blanking) zones and the AMS tank height, and sets LRV at the lower nozzle and URV at the upper nozzle (clamped to the vessel) for the measuring span.
How do you find the null zones and LRV/URV span for a GWR bridle?
From the bridle geometry: enter the upper and lower nozzle elevations, the flange face (upper reference), and your probe length. LTconfig returns the upper and lower null (transition and end blanking) zones, the AMS tank height, and the measuring span, anchoring LRV at the lower nozzle and URV at the upper nozzle (clamped to the vessel). It is a field commissioning reference, not a calibrated record.
How do you replace a displacer with guided wave radar (GWR) in a chamber?
Reuse the existing displacer chamber and bridle taps: set LRV at the lower nozzle and URV at the upper nozzle (clamped to the vessel). Enter the nozzle elevations, the flange face, and your GWR probe length, and LTconfig returns the upper and lower null (blanking) zones and the LRV/URV span for the retrofit.
What is the difference between LRV and URV?
LRV (Lower Range Value) is the process level the transmitter outputs as 4 mA / 0%; URV (Upper Range Value) is the level it outputs as 20 mA / 100%. The difference, URV minus LRV, is the measuring span.
What is a strapping table?
Strictly, a strapping table charts tank volume against height for custody transfer. LTconfig builds the field equivalent: a user-entered setpoint table listing the level (and corresponding mA) at the alarm setpoints you choose, so you can look up what the transmitter should read at each one. It comes from the LRV/URV range and your setpoints, not a custody calibration.
What is suppressed or elevated zero?
Suppressed or elevated zero means the 4 mA point (LRV) is not at the tap or vessel bottom. Because LTconfig anchors 4 mA and 20 mA to the levels you enter, it handles a suppressed or elevated zero directly.
Does LTconfig work for non-GWR level transmitters?
Yes. The horizontal vessel volume and the 4–20 mA level transmitter span (LRV, URV, and measuring span) work for any 4–20 mA level transmitter — differential pressure (DP), displacer, capacitance, or guided wave radar. Only the bridle and chamber configurator (the null zones and AMS tank height derived from probe and nozzle geometry) is GWR-specific.
Works with guided wave radar level transmitters such as Rosemount 5300-series, AMETEK Magnetrol Eclipse, and Endress+Hauser Levelflex. LTconfig is an independent tool, not affiliated with or endorsed by any manufacturer; product names are for compatibility reference only. Always confirm against the transmitter’s own manual.
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