12
3.2.
When Building Into a System
Errors due to a static charge and measures to take
When the ambient humidity is less than 45% RH, insulators such as plastic or glass are prone to
static electricity. When charged material comes close to the balance, a pulling force is generated
by static induction between the charged material and the weighing pan. This causes an unstable
weight value.
To protect the balance against a discharge generated by charged material when it comes close
to the balance, be sure to earth ground the weighing unit and the display unit.
Note that static electricity generated by static induction will not be canceled by earth-grounding.
Use a humidifier or the AD-1683 DC static eliminator,
Measures to take (Plastic is used in the examples below. They can be applied to glass, too.)
When the sample or devices are plastic
Use a static eliminator that generates no air blow such as the
AD-1683, DC static eliminator, to remove static electricity.
Place the sample in a container that is made of a conductive
material such as metal and that can be sealed, and then
weigh it.
When the sample is powdery
When the balance is used in combination with a feeder for
batch weighing of powdery samples, samples may be
charged by rubbing sample particles against each other.
Use a static eliminator and perform weighing while
removing static electricity.
When the sample container is made of material that is prone to static electricity such as plastic
Cover the outside of the container with a metal such as aluminum foil.
Apply an anti-static agent onto the container.
When making a breeze break using plastic
Apply an anti-static agent onto the breeze break.
Use a conductive acrylic fiber.
When plastic exists in the balance installation site
Cover the plastic with a grounded conductive material.
Apply an anti-static agent onto the plastic.
When an operator is static charged
If an operator’s clothes are static charged, especially in winter, it may be a cause for
unstable weight values.
Charged plastic breeze break
The pulling force
causes an unstable
weight value
A pulling force generated
between the charged
sample and the balance
causes an unstable weight
value.
Weighing unit
Charged sample
Metal case
Charged
material
Grounding
