A&D HD-30KA ACAI, Fine Unit Weight, Calibration & RS-232 Option Guide
- pete8781
- Jul 31
- 2 min read
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A&D HD-30KA fine counting mode allows a 0.25 g minimum storable unit weight while direct weighing readability remains 5 g. Standard mode uses 1 g minimum unit weight. The manual explains that reducing the minimum unit-weight setting does not itself improve counting accuracy; accuracy still depends on scale performance and consistency of the pieces. That is why sampling and ACAI matter as much as the mode selection.
Sample size and ACAI
Start with 10 pieces or select 5, 25, 50, 100 or another sample where supported. For lighter pieces, larger sample sizes generate more total load relative to the 5 g scale division. ACAI requests/adds more pieces and recalculates the average. A&D’s manual explicitly notes larger samples improve results when unit weights are small or inconsistent.
External calibration and gravity effects
Calibration uses the protected CAL switch and an external known mass. Level/stabilize the scale before adjustment and verify independently afterward. The HD platform also includes gravity-compensation settings for location changes, but routine users should avoid altering calibration-related configuration without a defined procedure; moving a scale to a different region is a reason to verify it with known weights.
Comparator troubleshooting
Comparator can judge count or weight, can require stable data, and can sound the buzzer for different conditions. If the numeric result is correct but HI/OK/LO behavior is wrong, inspect comparator mode and limits before touching calibration. If both displayed weight and comparison fail against known references, investigate calibration, pan contact or service.
Optional data interfaces
HD-03/OP-03 adds RS-232C, HD-05/OP-05 provides current-loop serial output, and HD-04/OP-04 provides comparator relay. The serial interface supports command/stream modes, multiple data formats and selectable baud rates. If the local display passes verification but the PC receives wrong values, troubleshoot serial format/settings before recalibrating the scale.
Frequently asked questions
Standard minimum unit weight? 1 g. Fine selectable minimum? 0.25 g. Direct readability? 5 g. Does selecting 0.25 g guarantee better count accuracy? No. What improves light-part accuracy? Larger representative sample plus ACAI. Is calibration external? Yes. Is RS-232C standard? No, optional. What if comparator is wrong but weight is right? Check comparator settings first.
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