Chinese
Spanish
Russian
Portuguese
French
German
Indonesian
Thai
Vietnamese
Arabic
Italian
Turkish
Polish
Japanese
Multi-tank level monitoring can display a convincing site total assembled from measurements taken minutes apart. During transfers between tanks, that total may temporarily count material twice or omit it. A dashboard refresh time does not prove that every tank reading represents the same moment.
Multi-Tank Level Monitoring Needs a Reporting-Time Rule
Define whether the total represents the latest available readings or an estimate at a common reporting time. State the allowed age and time spread for the intended use. An operational trend may tolerate more skew than a transfer reconciliation, but neither should hide missing or stale contributors.
Suppose tank A is read before a transfer and tank B after receiving it. Adding those two values can overstate total stock, although both individual readings were valid when taken. This is a timing example, not a radar accuracy defect. Recalibrating either transmitter cannot correct the asynchronous total.
| Case | Show | Total rule |
|---|---|---|
| Fresh set | Each tank's acquisition time and validity. | Use the agreed time-window test before presenting a current total. |
| Late tank | The older reading and its age. | Flag or withhold the total according to the approved limit. |
| Missing tank | Which contribution is unavailable. | Label any partial sum explicitly; do not silently insert zero. |
| Time uncertain | Clock or acquisition-time uncertainty. | Do not claim synchronized inventory without a defensible time basis. |
Add comparable quantities, not tank heights
Do not add liquid heights in metres and label the result as total stock. Each tank needs its own level-to-volume relationship, including its geometry or approved tank table. Different tank shapes and sizes can contain different volumes at the same indicated level.
For a volume total, convert each contribution to the agreed volume unit and calculation basis before aggregation. For a mass estimate, identify the applicable density and operating-condition assumptions as well. Do not mix observed tank volume, temperature-corrected volume and mass under one unqualified total.
Correct conversion is necessary but does not solve the timing problem. Even properly calculated volumes can double-count a transfer if their acquisition times differ. Retain the calculation revision and original acquisition time for every contribution so the total can be interpreted and reproduced.
Separate Measurement Capability From Platform Behaviour
MV-RD12 is a liquid-level radar with ordered analogue or serial electronics. The receiving PLC, gateway or historian determines how acquisition times and inventory totals are recorded. Confirm available instrument status separately; do not assume the radar supplies a timestamp, storage function or multi-tank total merely because it has a digital interface.
Ask the integrator how polling delays change when one device fails to respond. A shared display refresh can mask unequal data ages. Preserve the acquisition time for each value and distinguish it from server reception time. The range and units revision guide covers a different requirement: ensuring that all values retain the correct physical meaning.
Test a Transfer, Not Just a Static Dashboard
Use a safe controlled process or a clearly identified simulation to create changing values across two tanks. Introduce the permitted communication delay and check the total's qualification. Then remove one contribution and verify that the display explains the missing coverage. Agree the rule before testing rather than choosing a tolerance that makes the demonstration pass.
Site-Total Questions
Q1. Should old readings be interpolated to a common time?
Only when the application accepts an explicitly labelled estimate and its assumptions are justified. Unknown transfers or invalid measurements can make interpolation misleading. Keep measured and estimated totals distinguishable.
Q2. What information is needed for integration pricing?
Provide tank count, output interfaces, transfer behaviour, reporting interval and permitted data age. Include the required partial-total and invalid-total displays so their implementation is part of the scope.
Summary
Approve the timing rule alongside the MV-RD12 measurement configuration. A useful site total identifies which tanks contributed, when they were measured and whether the result is suitable for the current operational decision.
