Chinese
Spanish
Russian
Portuguese
French
German
Indonesian
Thai
Vietnamese
Arabic
Italian
Turkish
Polish
Japanese
A tank radar retrofit has two separate acceptance questions: does the new assembly fit the vessel correctly, and does the reported value still refer to the same physical level? Matching the flange bolt pattern answers neither question completely. An adapter can restrict the signal path or move the distance reference while the transmitter continues to display a plausible reading.
Keep an old-to-new comparison beside the drawing
Before removing the existing instrument, retain its identification, installed dimensions and usable configuration backup. Note which value the PLC receives and how it is scaled. A maintenance record that contains only the model number may omit the nozzle extension or offset that made the old installation work.
Measure the available connection rather than trusting a nominal size on an old drawing. The relevant opening includes the nozzle interior, lining, welds, reducer and any existing valve. Only inspect an isolated vessel or connection using the site's approved procedure; a replacement survey is not permission to open process equipment in service.
| Comparison item | What to record for both assemblies |
|---|---|
| Mechanical fit | Connection standard, sealing face, clear bore, adapter stack and installed antenna position, not just bolt spacing. |
| Distance reference | The manufacturer's stated reference plane and its elevation relative to the plant's chosen level datum. |
| Process exposure | Antenna, seals and connection materials, plus the documented limits for the specified assembly. |
| Electrical function | Power and wiring, assigned output variable, scale, fault response and any digital interpretation used downstream. |
| Removal space | Access to fasteners and terminals, lifting or withdrawal space, and the way the antenna can be inspected later. |
Use this comparison to identify what can be retained and what needs a fresh check. Do not call a replacement interchangeable until the relevant dimensions and functions agree. An instrument that can be made to work after mechanical and PLC changes is a retrofit solution, not necessarily a direct substitute.
Tank radar retrofit adapters must be assessed as an assembly
A reducer can provide the right flange while creating an internal step close to the antenna. A spacer can move the antenna farther into a recess. An existing valve can present an aperture or internal feature that was not shown on either supplier's drawing. Put all these parts on one section with their finished dimensions.
Compare a proposed MV-RD14G compact lens assembly with an existing horn installation using the actual antenna positions. The smaller antenna may make a particular arrangement feasible, but it does not approve the old nozzle, valve or adapter automatically. Request review of the full installed path.
Mechanical suitability also includes materials, seals and assembly ratings. Matching the pressure marking of one flange is not sufficient evidence for the complete stack. Have the responsible personnel review modifications and any required inspection or testing before the vessel returns to service.
Calculate the reference change before applying an offset
For a top-mounted level calculation, distinguish measured distance D from the reference-to-zero distance E. With the simple relationship level = E - D, moving the antenna reference changes both distances for an unchanged liquid surface.
Consider a geometric example, not a site measurement: the old reference is 5.00 m above the zero datum and the surface is 2.00 m below it, giving 3.00 m level. If the new reference is 0.15 m higher, the corresponding distances become E = 5.15 m and D = 2.15 m. The level remains 3.00 m. Retaining E = 5.00 m would instead calculate 2.85 m.
The correction must be assigned once. If the transmitter is configured for the new reference and an old PLC offset is also retained, the correction can be duplicated. Trace the calculation from the local distance through every conversion that depends on it, including a tank table or remote display.
This calculation does not fix an antenna recessed into an unsuitable nozzle. A numerical offset changes the reported value; it cannot remove an interfering reflection or establish mechanical compatibility.
Recheck the functions that changed, including those hidden in the PLC
The replacement may provide a different configured variable even if it uses the same 4-20 mA cable. A distance span and a level span are not equivalent. Confirm the new terminal arrangement, supply and output assignment from its documentation before energising the loop.
For a digital replacement, verify the required data map and representation rather than carrying over the old addresses by assumption. A response to a Modbus request is not proof that the PLC is reading the intended quantity. The level-data integration guide covers scaling and status handling in more detail.
An MV-RD15G liquid configuration may be considered where its antenna and process configuration fit the duty. Similarity to another 80 GHz housing does not establish identical wiring, measurement limits or process ratings. Attach the selected version's documents to the retrofit record.
Define the handover before the shutdown
Agree which measurements will demonstrate success, how temporary indication will be handled and what happens if an unresolved condition prevents acceptance. Retain the previous records and identify a feasible fallback where the project requires one. Do not promise that the old instrument can simply be reinstalled after an irreversible nozzle modification.
After the work, compare a credible local distance and level reference, then follow the output into the control system. Check required alarm and invalid-measurement behaviour through the authorised test procedure. Update the as-built section, settings and device identity. If full process conditions were unavailable, identify the remaining operating test rather than treating a workshop simulation as complete acceptance.
Replacement questions
Q1. Can the original false-echo settings be copied?
Do not assume they remain valid after changing the antenna or its position. Preserve them as historical evidence, then assess the new installation using the delivered instrument's procedure and a known surface position. The new assembly may see different fixed reflections.
Q2. Is a constant reading difference always a reference error?
No. A reference change is one possible cause. Check the actual surface, selected target, units, span and any receiver calculation. A constant offset should be applied only after its physical or configuration cause is established.
Q3. What should be sent to check a proposed replacement?
Provide the old model and configuration, a section showing every mounting component, process conditions, required output and the reason for replacement. Include known changes since the old unit was installed. Ask for identified deviations, not a general assurance that the new unit is equivalent.
Summary
A controlled retrofit reconciles the mounting assembly, physical datum and receiving system before the old records are retired. Send the old-to-new details through the METRAVON replacement enquiry. Keep numerical corrections separate from mechanical corrections, and verify each in the completed installation.
