Method for determining the necessity of adjusting a high-resolution electronic balance

• US 5,056,050 A
• Filed: 10/06/1989
• Issued: 10/08/1991
• Est. Priority Date: 05/23/1986
• Status: Expired due to Term

• Current Assignee: Mettler Toledo GmbH
• Original Assignee: Mettler-Toledo AG (Mettler-Toledo International Inc.)
• Inventors: Meier, Linus, Fuchs, Fritz, Reichmuth, Arthur
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): MELNICK, STEVEN A
• Application Number:
  US07/418,927
• Time in Patent Office: 732 Days
• Field of Search: 364/567, 364/571.01, 364/571.03, 177/25.19, 177/25.11, 177/1
• US Class Current: 702/101
• CPC Class Codes: G01G 23/01 Testing or calibrating of weighing apparatus

Abstract

In a process according to the invention for automatic calibration and/or linearization of a high-resolution electronic balance, point values are assigned by a function to the disturbance variables (parameters) that can affect the weighing result. A calibration and/or linearization is indicated or triggered when the accumulated point values reach a triggering point value (Xa) that is presettable, balance-specific and/or dependent on the environment. The calibration and/or linearization can also be triggered when the accumulated point value of a single disturbance variable reaches a triggering point value which is below point number (Xa).

Claims

1. A method for determining the necessity of adjusting a high-resolution electronic balance comprising the steps of:

for each of a plurality of parameters that interfere with the accuracy of a weighing result, monitoring said parameters to detect changes in said paramaters affecting accuracy of a weighing result;

converting each detected change in a parameter into a numerical point value that is a function of the magnitude of the change, using different functions to convert the changes in at least some of the different parameters;

accumulating the numerical point values to obtain an accumulated point value associated with the changes in all the different parameters; and

determining whether the accumulated point value has reached a triggering point number.

2. The method of claim 1 wherein the parameters in which changes are detected are selected from the group consisting of:

change of temperatures inside or outside the balance, air pressure, inclination of the balance, relative or absolute humidity, gas composition, air or gas density of the environment, electric or magnetic fields, vibrations that have occurred since a previous weighing, radioactivity, aging of components of the balance, the position of the moon and sun, and the tides.

3. The method of claim 1 further comprising the step of calculating the triggering point number as a function of the triggering point number of at least one previous calibration of the balance.

4. The method of claim 1 further comprising the steps of:

accumulating the numerical point values for each of said parameters to obtain a plurality of accumulated point values, each associated with the changes in one of the different parameters;

determining whether at least one of the plurality of accumulated point values has reached a predetermined point value, said predetermined point value being smaller than said triggering point number; and

,

if said predetermined point value has been reached, indicating that an adjustment of the balance is necessary.

5. The method of claim 1 further comprising the step of calculating the triggering point number as a function of at least one previous linearization of the balance.

6. The method of claim 1 further comprising the step of calculating the triggering point number as a function of at least one of the parameters in which changes are detected.

7. The method of claim 1 further comprising the step of varying the triggering point number.

8. The method of claim 1 further comprising the steps of:

accumulating the numerical point values for each of said parameters to obtain a plurality of accumulated point values, each associated with the changes in one of the different parameters;

determining whether at least one of the plurality of accumulated point values has reached a predetermined point value, said predetermined point value being smaller than said triggering point number; and

,

if said predetermined point value has been reached, initiating an adjustment of the balance.