DP LEVEL CALIBRATION

DP Level Calibration produces the range values for a hydrostatic level transmitter, so its output spans the full physical level range of a specific vessel, impulse-line arrangement, fill fluid and process fluid. Vapour-phase density is compensated at operating conditions.

Capabilities

• Lower and upper range values and span, checked against the transmitter’s own physical range limits.
• Four impulse-line configurations: dry leg, wet leg, remote seal, and open to atmosphere with no low-side tap.
• Fill fluid entered directly or selected from presets — water, ethylene glycol, propylene glycol, silicone oil, glycerin — with reference densities built in.
• Process fluid as a water/air preset, a single hydrocarbon stream, or separate liquid and vapour streams where their compositions differ.

Why the results hold up

Range values come from a hydrostatic balance across each tap, with tap positions and level marks treated as signed heights from the transmitter centreline, the same relationship manufacturers’ configuration procedures use. For wet-leg and remote-seal arrangements, the fill fluid’s own head is calculated and subtracted. Where the process fluid is a defined composition, liquid and vapour densities come from the Peng-Robinson equation of state at operating pressure and temperature, so the vapour-phase head is compensated at actual conditions rather than neglected.

Scope

Process and fill-fluid densities are each held constant through the calculation; a strongly stratified vessel carries more error than the result implies. Dynamic effects on the reading — turbulence, foam, surface agitation, tap location — are installation matters outside the calculation. Where the loop feeds a safety instrumented function, its configuration must be independently checked against that system’s own requirements; see the Software & Engineering Disclaimer for the suite-wide statement on safety-critical use.