VB302A-300 Precision Scale [300g x 0.005g], powered AC adapter (included) or 6AA
batteries (not included), 4.5 inch round weigh pan. Calibration requires 200 gram calibration
weight which is now included with the balance.
We're letting the cat out of the bag. There are many ways to build an inexpensive
scale. From the appearance, every digital scale looks more or less the same.
Metrologically they are not all the same and more like night and day.
Reputable scale manufacturers are finding it increasing difficult to differentiate
themselves with commercial low cost scale companies. If a scale that is
good enough to weigh cookies is not good enough to weigh your products, please
read on.
An easy way to build a low cost scale is to use a low cost inaccurate sensor.
Manufacturers use software to compensate the common linearity in strain gauge
load cell sensors. Cheap sensors inherently have linearity problems.
For example, if you calibrate the scale at zero and full scale capacity, these
two weighing points are accurate. Anything in between may be an S shape,
C shape, reverse C shape or multiple S shape curves on a linearity chart.
Software is used to correct these weighing points to show you a display weight
that you want to see but in reality the scale is still highly inaccurate.
The problem lies with the weighing sensor the software, no matter what cannot
correct all these errors. When you start stacking the scale with more and
more weights, the weigh may be correct, but when you take them off one by one,
the errors are compounded. This is hysteresis.
Place the weight and let it sit for 10 minutes, this is creep. Put the same
weigh over and over a few times, this is the repeatability
test. There are also temperature span errors and corner shift errors.
Software cannot compensate all these.
Manufacturers also use different software filtering techniques to reduce the display
error like averaging the display fluctuations or locking the displays.
The heart of weighing is the sensor (aka loadcell).
On the VB302A Series, VMC only uses the German HBM load cell, they are highly
reputable and widely acceptable worldwide to be one of the top manufactures of
load cell sensors. Good sensors can cost 10 times more than the less known
sensors. The result is that you get an accurate and repeatable weighing reading
on your scale/balance.
A good sensor alone does not translate to good scale. Check out the photos
below. The mounting to the load cells and weight transfers from the
scale platform to the sub-platter to the load cells and to the base of the scale
is all designed and manufactured with added heavy & rigid steel columns to
prevent bending or flexes that might cause errors in weighing. The 4 adjustable
footing screws are stainless steel to provide stiffness to the entire scale.
VB302A operates on AC adapter or 6 AA batteries (battery not included) and features
a fine hairline finishing on the stainless steel platter. Additional features
include a green backlight LCD with large display for easy viewing and the audible
beep when keypads are pressed.
Common applications are in chemistry labs, medical labs, science labs, hospitals
and clinics, universities, jewelry, beads & colored stones, paint and powder
mixing, under table weighing for determining density, pharmaceutical weighing
and calibration labs.
Virtual Measurements & Controls (VMC) gives you value, quality and satisfaction.
VMC is a young 10 year old company with speed and agility to design, manufacture
and bring the best products to you but without the overheads of other scale manufacturers.
The savings are all yours when you select the VB-302A-300 Portable Scale.
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Instruction Manual
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