A&D FX-5000i vs FZ-5000i: External vs Internal Calibration Buyer Guide
- pete8781
- Jul 31
- 3 min read
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The A&D FX-5000i vs FZ-5000i choice is primarily a calibration-workflow decision, not a capacity or readability decision. Both are 5200 g × 0.01 g members of A&D’s Compact Super Hybrid Sensor family with fast stabilization, RS-232C, counting, percent, statistics, comparator and underhook capability. FX-5000i uses external calibration weights. FZ-5000i adds an internal calibration mass and automatic/internal calibration functions. Neither choice should be made on an assumption about legal-for-trade status: the current U.S. A&D catalog does not list FX-5000i as NTEP and there is no current FX-5000iN model.
Shared weighing platform
Both models provide 5200 g capacity with 0.01 g readability, approximately 0.01 g repeatability, ±0.02 g linearity and roughly one-second stabilization in FAST mode under good conditions. Both use a 150 mm diameter stainless pan and a compact body around 193 × 262.5 mm. In normal weighing performance, the two models are intended to feel very similar because they share the same core sensor/platform architecture.
FX-5000i: external calibration workflow
FX-5000i requires a known external mass when calibration adjustment is performed. MNM lists 5000, 4000, 3000, 2000, 1000 and 500 g accepted values. This is a strong fit for laboratories that already manage calibration weights and want a simple balance without an internal motorized mass. The user controls when calibration occurs and can integrate it into a scheduled verification/calibration program.
FZ-5000i: internal calibration convenience
FZ-5000i contains an internal calibration mass, allowing calibration without retrieving and handling an external weight for routine adjustment. Internal calibration is useful in busy labs, shared workstations and environments where temperature changes make more frequent adjustment desirable. It reduces handling effort, but it does not eliminate the need for independent verification with external known weights when the quality system requires evidence of performance.
Which is better for a controlled laboratory?
Choose FX when the lab already has appropriate weights, external calibration is written into the SOP and lower acquisition complexity is preferred. Choose FZ when internal calibration reduces operator burden or supports more frequent adjustment. In either case, verify performance with independent reference weights at meaningful points and keep the balance on a stable, level bench away from drafts, vibration and static.
Shared RS-232C and interface choices
Both families include RS-232C and support optional Quick USB, Ethernet and internal rechargeable battery configurations. The internal USB/Ethernet/battery options are mutually exclusive, so interface planning is the same on FX and FZ. Both can participate in PC, printer, network or logger workflows, and both support GLP/GMP/GCP/ISO-style output for quality documentation.
Counting, percent, statistics and comparator
The shared operating functions mean an application does not need FZ simply for ACAI counting, percent weighing, statistical calculation or comparator limits; FX-5000i already provides those features. Pick FZ for calibration convenience, not because it has a fundamentally different process-function set. Likewise, pick the required interface based on data workflow rather than calibration type.
Underhook and special weighing
Both support underhook weighing for suspended/density applications. The fixture, support structure and hanging load must be mechanically isolated so nothing touches the bench or floor. The balance should be verified in the actual underhook configuration when the result is important. The FXi-12 animal pan accessory is not mapped to the 5000i model, so a buyer should not choose between FX and FZ expecting that specific accessory to be available at 5200 g capacity.
NTEP/legal-for-trade status
For FX-5000i, the answer is no: A&D’s current U.S. model matrix does not identify it as NTEP and does not list an FX-5000iN. Do not select FZ-5000i merely assuming internal calibration creates legal-for-trade approval either; trade status must be established for the exact approved model/configuration. If the weight will determine a commercial transaction, choose a product explicitly certified and sold for that use instead of treating the FX/FZ calibration feature as a certification substitute.
Who should choose which?
Choose FX-5000i for laboratories, formulation and production stations that already manage calibration weights and want 5.2 kg capacity at 0.01 g. Choose FZ-5000i when internal calibration reduces daily friction or supports more frequent adjustment. Choose a different certified model for legal-for-trade work. Choose a smaller 0.001 g model when finer resolution is more important than 5 kg capacity, and choose a platform scale when the vessel cannot sit safely on the 150 mm pan.
Frequently asked questions
Do FX-5000i and FZ-5000i have the same capacity/readability? Yes, 5200 g × 0.01 g. What is the main difference? FX uses external calibration; FZ adds internal calibration. Does FX-5000i have RS-232C? Yes. Do both support counting/statistics/comparator? Yes. Is FX-5000i NTEP? No. Is internal calibration the same as legal-for-trade certification? No. Does FX support underhook weighing? Yes. Which is better if the lab already owns calibrated weights? Often FX. Which is better if operators want one-touch internal adjustment? FZ.
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