A&D Co., Ltd. (headquarters: Toshima Ward, Tokyo, Representative Director and President, Yasunobu Morishima) has launched the HW-CEP/HV-CEP series of intrinsically safe, explosion-proof digital platform scales that can be used in type 0 to type 2 hazardous locations, including factories.

Key Features of the HW-CEP/HV-CEP Series

  • Affordable selection of capacities and readabilities for excellent explosion protection
  • High-speed measurement—response within 1 second (for the HV-CEP series)*1
  • Multi-colored 5-step LED comparator lights
  • Auto-tare and negative comparison functions realizing “take-away” check weighing
  • Highly-visible, LCD display (26 mm character height) with white backlight
  • Quick and easy settings using the alphanumeric keypad
  • Key lock function to prevent operators from making changes to the scale settings
  • IP65 dust & waterproof base unit with a stainless steel (SUS430) pan
  • Adjustable response characteristics depending on the degree of drafts and vibrations at the location
  • Display hold function
  • Counting mode function
  • Accumulation (M+) function
  • Approx. 1,500 hours of operation with four D batteries*2
  • Auto power OFF function to save battery power
  • Display angle adjustable to five levels

*1 Time required for the last digit to settle (the stabilization mark will be lit one second after), which is subject to the weighing environment, response characteristic setting and how the target object is placed. With the HW-CEP series, response typically takes not more than 1.5 seconds.
*2 With LED and backlight OFF (or approx. 1,000 hours with LED and backlight ON). The batteries to be used are specified: DURACELL MN1300, ENERGIZER E95, or Panasonic LR20 (XJ).

Main Specifications

Capacity3 kg6 kg15 kg15 kg30 kg60 kg60 kg150 kg220 kg
Readability0.001 kg0.002 kg0.005 kg0.005 kg0.01 kg0.02 kg0.02 kg0.05 kg0.1 kg
Weighing pan250 mm × 250 mm330 mm × 424 mm390 mm × 530 mm
Capacity10 kg60 kg100 kg220 kg
Readability0.001 kg0.005 kg0.01 kg0.02 kg
Weighing pan250 mm × 250 mm330 mm × 424 mm390 mm × 530 mm

HW-CEP/HV-CEP Series Product Page

A&D Company, Ltd. (headquarters: Toshima Ward, Tokyo, Representative Director and President: Yasunobu Morishima) has converted the RS-232C output for weighing instruments to Modbus RTU (RS-485), and released the AD-8551R, a Modbus converter that allows up to 31 weighing instruments to be connected to a PLC and other devices by multidrop.

Main Features of the AD-8551R Modbus Converter

  • A converter that converts RS-232C communication from electronic balances and scales into RS-485 communication
  • With RS-485, weighing data collection and management can be performed for up to 31 units can be performed on a single host device, such as a PLC or PC..
  • Compact and attachable to a DIN rail
  • Re-zero (zero-reset) processing for the weighing instrument can be can be performed from a PLC.
  • In the RS-485 communication method, communication by Modbus RTU (Modbus RTU mode) or communication by ASCII code commands (command mode) can be selected.

AD-8551R Product Page

A&D Co., Ltd. (Head Office: Tokyo, Toshima Ward, Representative Director and President: Yasunobu Morishima) has launched the new “BM-5” and “BM-5D” micro electronic balances, which allow for high-precision weighing from 1μg and are ideal for pre-processing, such as element analysis and mass analysis.
Both have a 5.2g weighing capacity, and are equipped with a windless ionizer as a countermeasure against static electricity, and a desktop breeze break (M) as standard.

Main Features of the “BM-5” and “BM-5D” Micro Balances

  • BM-5 (Single-Range Model/High-Performance Series)
    • Top micro electronic balance model made by A&D
    • Weighing capacity of 5.2g, minimum display of 0.001mg (1μg)
    • 1g repeatability within the weighing capacity, with a standard deviation of 0.0012mg (1.2μg)
    • Minimum weighing value of 2.0mg, in accordance with the 2.0mg minimum weighing value listed in Chapter 41 of the U.S. Pharmacopoeia (USP)
  • BM-5D (Smart Range Model/Basic Series)
    • Weighing capacity of 5.2g, minimum display (from 2.1g) 0.001mg (1μg) / (from 5.2g) 0.01mg (10μg)
    • 1g repeatability within the weighing capacity, with a standard deviation of 0.004mg (4μg)
    • Minimum weighing value of 5.0mg
    • Even if a tare weight that exceeds the precision range weighing capacity is used, weighing within the precision range (minimum display of 0.001mg) is possible
  • Features shared by BM-5/BM-5D
    • Equipped with a direct-current windless ionizer for electrostatic discharge as standard (patented)
    • Equipped with a desktop breeze break (M) as standard
    • For anti-static purposes, a conductive glass made of metallic film is utilized for the breeze break
    • A weighing pan that uses a latticed filter, which is less susceptible to breezes, is included as standard.
    • Includes a backlit LCD display that increases visibility and reduces eye fatigue
    • A cross-slide door that allows for both hands to be used to improve performance.
    • Built-in calibration weight
    • A password function is provided as a security measure.
    • Performance evaluation in the installation environment is possible using AND-MEET, a weighing environment evaluation tool.

BM Series Product Page

A&D Company, Ltd. (Head Office: Toshima Ward, Tokyo, Representative Director and President: Yasunobu Morishima) has launched the AD-1676 tabletop breeze break (M) for micro and semi-micro (0.01mg) electronic balances.

Main Features of the AD-1676 Desktop Breeze Break (M)

  • For micro and semi-micro (0.01mg) electronic balances
  • Significantly reduces weight value error due to ambient air convection around the balance
  • Solves the problem of electronic balance measuring errors caused by wind and drafts from air conditioners and/or human movement
  • Anti-static resin on transparent panels reduces the effects of static electricity
  • Holes installed on the back panel to run cables for the AC adapter and communication cables.
  • Sliding doors on both the left and right sides

A&D Electronic Balances that Support the AD-1676 Desktop Breeze Break (M)

AD-1676 Product Page

Today’s topic regards minimum weight for balances and is based on information from the U.S. Pharmacopeia (USP), an organization that makes standards to ensure the quality of pharmaceutical products. The following is a summary of the contents of USP Chapter 41 Balances. 

“Unless otherwise stated, when substances must be accurately weighed for analysis, the measurement uncertainty (random or systematic error) of the weighing equipment used must be no larger than 0.10% of the measured value. For measurement uncertainty, repeatability is assessed by weighing one test weight 10 times and is satisfactory if twice the standard deviation of the weighed value, divided by the nominal value of the weight used, does not exceed 0.10%.”

The standard goes on to say that the minimum mass measured by a weighing instrument should be 2000 times the repeatability (defined by standard deviation σ) that is obtained through 10 successive measurements of the same, unchanging mass, such as a standard weight.

The wording of this standard appears to be incredibly difficult to understand at first glance. What it states, however, is simply that, considering 2 sigma (deviation of a 95% confidence interval), measurements carried out with this deviation below 0.10% are considered satisfactory for ordinary weighing.

However, is there any meaning to deciding a standard precision requirement for all measurement and weighing occurring in different situations? That is, for measurement and weighing sites, generally the required precision for each site is different. It is readily apparent that the required uncertainty for dealing with gold is vastly different than weighing candy. It is also necessary to consider what is lost and what is gained as a result of single-minded focus on pursuing precision. In particular, microanalysis is an industry that has the some of the strictest requirements for weighing in modern society, requiring minimum weight at the milligram level. For these measurements, a deviation of 0.1% for a weight of, say, 1 mg would require a repeatability of half a microgram (1 mg / 2000 = 0.5 μg). The only type of balance with the capacity to guarantee such minute repeatability is an ultra microbalance. The measurements required by this standard at that infinitesimal scale would dictate the purchase of such an ultra microbalance. Unfortunately, these balances are not only extremely expensive but also incredibly difficult to use.

As I mentioned previously in Development Story 38, maintenance of the weighing environment and proficiency in weighing operations are of utmost importance. Currently, what seems most problematic is the fact that balance manufacturers highlight only the importance of the minimum weight and the standards for it. They then sell balances and afterwards leave the problems concerning errors arising from installation environment and how the balance is operated unsolved. They make no attempt to resolve these problems. In the end all that remains is an abundance of expensive dust-covered paperweights that happen to be called “ultra microbalances”. This lack of support is responsible for the deterioration of trust in weighing device manufacturers.

Under these circumstances, figuring out how best to deal with these problems at the places where these balances are actually used has become quite an issue. Although the minimum weight was first defined as the standard deviation times 3000 and now has been revised to 2000 times the standard deviation. This only served to prove the standard was a theory only on paper that failed to consider the work actually being done at the various laboratories. From my experiences abroad and at domestic laboratories, there were very few places that I thought had suitable weighing environments for microbalances, namely some public institutions and balances manufacturers in Europe and research organizations in Japan. In elemental analysis a calibration curve is used on the sample to be measured and always gives a result. However, this requires confirmation of the precision of the device used for this analysis.

In the past, the minimum display of measurement devices including analytical balances was used as a reference value and there was an unspoken rule that measurements were taken from the next most significant digit from the minimum display. The reason for doing this was that balances had many display digits and were subject to many disturbances from operation as well as from the environment which made it difficult to determine stable weights from the minimum display digit. People realized that 10 times the minimum display was required as the determinable display. There was also rule that stated that 1000 times the determinable display would be sufficient to obtain results whose uncertainty is within 0.1%. With a repeatability of 3 micrograms, the 3 sigma value is 10 micrograms allowing for accurate weighing of 10 mg samples. This means that the current minimum weight is nothing more than the standardization of the previous unspoken rule of measurement.

Given all that has been said above, while the idealistic minimum weight standard may be reasonable for general purpose balances or general analytical balances with 0.1 mg minimum displays, it is not appropriate for microbalances. When it is not necessary to confirm 0.1% at the place of analysis, instead of blindly following the standard, a flexible response that takes into account the necessary weighing precision is vital. Using the example of balance repeatability, if the minimum weight is redefined as 1000 times the standard deviation balance users would determine that what really should matter is that weighing precision is suitable to one’s intended purpose without getting caught up in a spec war about microbalance repeatability. Also, given similar expenditures, instead of spending 100% of the purchase cost on the balance itself, there is value to be had in investing in creating a worry-free weighing environment through the proper maintenance of the measurement environment or participation in training that ensures proper weighing techniques.