A&D GR Series GR-300 - Manual (Page 7)

Cautions during use (To get best performance)
Note the following items to get accurate weighing data.
□ Press the | RE-ZERO | key before each weighing to prevent
possible error.
□ Calibrate the balance periodically so as to cancel possible
weighing error.
□ Make each weighing quickly to avoid errors due to changes
in the environmental conditions.
□ Close glass doors to keep out drafts.
□ Do not drop things upon the weighing pan, or place a
weight beyond the range of the balance on the weighing
pan.
□ Do not use a sharp instmment (such as a pencil or ball point
pen) to press the keys, use your finger only.
□ Toweighproperlywithaminimum display of 0.01 mg using
the GR-202, replace the breeze break ring with the fine
range breeze break ring. See page 8 for details.
□ Dischargestaticelectricityfromtheweighed matter. When
weighing material (plastics, insulator, etc.) could have a
static charge, the weight value is influenced. Try to keep
the ambient humidity above 45%RH or to use the metal
shield case.
□ This balance uses a strong magnet as part of the balance
assembly, so please use caution when weighing magnetic
materials. If there is a problem, use the underhook (on the
bottom of the balance) to suspend the material away from
the influence of the magnet.
□ Cancel the temperature difference between the weighed
material and the environment. When a sample is warmer
(cooler) than the ambient temperature, the sample will
lighter (heavier) than tme weight. This error is due to the
rising (falling) draft next the sample.
□ Take into consideration the affect of air buoyancy on a
sample when more accuracy is required.
2. Caution Page 6 Basic operation