Switching on

• Do not disconnect the balance from the power supply and always leave it switched on. This allows the balance to reach thermal equilibrium.
• When you switch the balance off, use the display key (on older models the tare key). The balance is now in standby mode. The electronics are still energized and no warm-up period is necessary.

TIP: We recommend a different warm-up time for each balance when it is first connect to the power supply. These are:

• Up to 12 hours for micro balances
• Approximately 6 hours for semi-micro and analytical balances
• Approximately 3 hours for precision balances

Apart from these guidelines, always observe the minimum times specified in the operating instructions.

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Minimize the weighing risk!

Leveling

• Align the balance. To do this, check that the air bubble is in the center of the level indicator. Use the leveling feet to make adjustments. You must then adjust the sensitivity of the balance. The exact procedure is described in the operating instructions for the balance.

TIP: To ensure and document that the balance is correctly leveled every time for example, to comply with GxP¹⁾ we recommend the Excellence Plus family of balances with the built-in automatic warning function “LevelControl”.

¹⁾ GxP Good Laboratory Practice (GLP) or Good Manufacturing Practice (GMP)

Adjustment

• Adjust the sensitivity of the balance regularly, especially
  • when you operate the balance for the first time
  • when you change the location of the balance
  • after leveling the balance
  • after major changes in temperature, humidity or air pressure.

TIP: If a fully automatic calibration following, for example, a temperature change is important to you, it would be worthwhile to acquire balances with “FACT,” which calibrate automatically. These models also allow you to extend the time interval for routine checks.

Reading

• Check that the balance displays exactly zero at the start of each weighing. Tare, if needed, to avoid zero errors.
• Read off the result only after the small round circle in the upper left of the balance display has faded. The weighing result is released through this stability detector.

TIP: The Excellence Plus line offers an advanced stability detector. These balances display unstable measurement values in blue. Once stability is regained, the display immediately changes to black and the circle in the upper left disappears. This allows you to identify a stable weighing result faster, safer and more reliably.

Weighing pan

• Always place the weighing sample in the middle of the weighing pan. This will prevent corner load errors.
• With micro and semi-micro balances, the weighing pan should first be loaded once briefly after a relatively long pause (>30 min) to deactivate the “initial weighing effect”.

Weighing vessel

• Use the smallest possible weighing vessel.
• Avoid weighing vessels made of plastic when atmospheric humidity is below 30-40 %. These conditions increase the risk of electrostatic charge.

Materials with a high degree of electrical insulation, such as glass and plastic, can become electrostatically charged. This can drastically distort the weighing result. For this reason, make sure you take the appropriate corrective measures (for more, see Electrostatics)

• The weighing vessel and the sample it contains should have the same temperature as the surroundings. Temperature differences can lead to aircurrents that distort the weighing result (see Temperature). After removing the weighing vessel from a drying oven or dishwasher, allow it time to cool before placing it on the balance.

• If possible, do not use your hands to place the weighing vessel in the weighing chamber. You could alter the temperature and atmospheric humidity of the weighing chamber and the weighing vessel, which would have an adverse effect on the measurement process.

TIP: Different taring container holders offer optimal conditions for error-free and safe weighing (see illustrations).

Round bottomed flasks on special taring container holders “ErgoClip Flask” and “MinWeigh Door”.

Draft shield

• Open the draft shield only as far as necessary. This will keep the climate in the weighing chamber constant, and the weighing result will not be influenced.
• Adjust balances that have an automatic and configurable draft shield, such as the instruments of the Excellence Plus family, so that the opening of the draft shield is minimal.

TIP: To make weighing simpler and more precise, even under the most challenging conditions, we recommend specific accessories for our Excellence and Excellence Plus families of balances. These balances will yield the best results, even when you are weighing extremely small samples with narrow tolerances under unfavorable ambient conditions. Our special draft shield “MinWeigh Door,” for example, is designed to be perfect for use in weighing cabinets. But it also offers advantages for “normal” weighing conditions. It can improve the repeatability of the net reading by a factor of about two!

Using “SmartGrid,” a weighing pan with a special grid structure, stabilizes weighing so well that the draft shield doors for 4-digit analytical balances can normally be left open during weighing.

Care of the balance

• Keep the weighing chamber and weighing pan clean.
• Use only clean vessels for weighing.
• The balance can be cleaned with conventional window-cleaning fluid.
• Do not use cloths that contain fusel oil.
• Do not brush contaminants into potential openings.
• Before cleaning, remove all removable parts, such as the weighing pan.

TIP: On Excellence and Excellence Plus analytical balances, each of the draft shield panes can be removed for cleaning in a dishwasher.