A&D launches BM-S semi-micro balances: 0.01 mg up to 101 g

A&D Company, Limited launched the BM-S series of semi-micro balances on October 29, 2026. The minimum display is 0.01 mg, which on the BM-255DS covers weighings up to 101 g and changes to 0.1 mg above that; capacity is 250 g on the BM-255DS and 120 g on the BM-125DS. A&D positions the series for the high-accuracy weighing asked for in research and development and in quality control.

The 0.01 mg reading holds with a tared container on the pan

The balance switches its minimum display between a standard range and a precision range according to the displayed value, and A&D says this lets it weigh a net sample to 0.01 mg even after a heavy container has been tared off. In A&D's specification table the precision range, where the 0.01 mg minimum display applies, runs to 101 g on the BM-255DS and to 51 g on the BM-125DS. Load a tare heavier than that and the display moves to the standard range, but as long as the total stays within capacity, pressing re-zero brings the balance back into the precision range for the sample itself.

Repeatability, as standard deviation, is given by A&D as 0.02 mg on the BM-255DS and 0.03 mg on the BM-125DS, both at a 50 g test load. List prices, excluding tax, are 325,000 yen for the BM-255DS and 295,000 yen for the BM-125DS.

Ten measurements on the internal weight put a number on the installed environment

Repeatability changes with where the balance stands, so the BM-S carries a function that takes ten measurements using the internal weight and displays their standard deviation. A&D says that running this function after installing the balance shows the repeatability in the installed environment. Airflow and vibration at the bench cannot be known before the instrument is there, and the same routine gives a figure that can be recorded once it is.

Sensitivity adjustment also runs off the internal weight. There is one-touch adjustment, and a setting that adjusts automatically as the ambient temperature changes. A calibration test, which checks accuracy without adjusting anything, can be run on the internal weight as well, and the result can be output as a maintenance record suited to GLP and GMP use.

Conductive glass shield, two draft rings, and weighing values straight to a PC

The draft shield uses conductive glass with a metal film, applied against static. Two draft shield rings come with the balance: a tall one that blocks airflow and convection, and a low one that is less likely to touch weighing paper or a filter.

External output is by RS-232C (D-Sub 9-pin), USB (Type-C) and a 3.5 mm stereo jack. The USB side switches between a unidirectional mode that needs no driver and sends values straight to a PC, and bidirectional communication. The balance itself stores up to 200 weighing values with date and time, plus the 50 most recent sensitivity adjustments.

Passwords run at three levels: administrator, user (up to 10 people) and guest. A&D says that putting the balance into key lock, so that it responds only to commands from an external device such as a PC, lets the user build a software system that prevents data tampering, with an audit trail and user authentication, and makes compliance with standards such as 21 CFR Part 11 possible as well. As A&D words it, the compliance is a property of the system built around the balance, not of the balance on its own.

What to settle before the balance arrives

A&D gives the minimum weighing value as a reference figure: 20 mg on the BM-255DS and 24 mg on the BM-125DS. The minimum sample weight a site can work to is generally taken to follow from the error it can accept and the repeatability where the balance stands, and A&D adds that if normal work is not near capacity, it is worth having a weight close to the actual target mass for daily checks. The result of the repeatability check is a measurement on the internal weight of about 200 g, which differs from the conditions behind the repeatability in the specification table, and A&D notes that it should be treated as a reference value.

Decide the split between daily checks and periodic calibration first. A&D recommends a 200 g weight (E2 class equivalent) for the BM-255DS and a 100 g weight (E2 class equivalent) for the BM-125DS, and recommends JCSS-calibrated weights for the sensitivity adjustment of high-resolution balances. The specification also carries A&D's note that the mass of the internal weight can change with the use environment and with age. How far an internal-weight adjustment counts as a record, and how often an external-weight calibration goes in between, is decided on the qualification and calibration-procedure side rather than by the instrument.