Electronic balance

• US 4,723,613 A
• Filed: 05/21/1986
• Issued: 02/09/1988
• Est. Priority Date: 05/21/1986
• Status: Expired due to Fees

• Current Assignee: OHAUS Corp. (Mettler-Toledo International Inc.)
• Original Assignee: OHAUS Corp. (Mettler-Toledo International Inc.)
• Inventors: Kroeger, James, Garlen, Daniel R., Stiles, George A.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US06/866,238
• Time in Patent Office: 629 Days
• Field of Search: 177/50, 177/164, 177/165
• US Class Current: 177/50
• CPC Class Codes: G01G 23/017 Securing calibration against fraud
• CPC Class Codes: G01G 23/163 involving digital counting

Abstract

An electronic balance having a stored setup routine for defining scale operating parameters. An indicating device, which may be interchangeably connected to a plurality of weighing platforms, is responsive to an identifying connector to select from a memory operating parameters related to an operational characteristic of the weighing platform during the setup routine. A plurality of multi-function manually actuated buttons permit user selection of operating parameters during the setup routine. A sealable switch is used to restrict access to the setup routine. The balance operates in weighing or parts counting modes and can display weight in the parts counting mode. The balance can also provide a user with an indication of whether a dead-load or span adjustment is necessary.

Claims

1. An electronic balance, comprising:

a means for generating data relating to weight, comprising an A/D converter;

a means for displaying the weight related data as a percentage of the dynamic range of the A/D converter; and

a means for modifying the weight related data so that the weight related data is within a predetermined portion of the dynamic range of the A/D converter.

2. An electronic balance as in claim 1, wherein:

the means for generating further comprises a transducer which generates an analog signal which is supplied to the A/D converter; and

the means for modifying comprises a span adjustment means including a programmable gain amplifier having first and second inputs connected to the transducer and an output connected to the A/D converter, and a dead-load adjustment means including a variable resistor connected to the transducer and one of the inputs of the programmable gain amplifier.

3. A method of operating the electronic balance of claim 2, comprising the steps of:

generating data relating to dead-load;

adjusting the variable resistor to bring the dead-load related data to within a first predetermined portion of the dynamic range of the A/D converter;

generating data relating to full capacity; and

adjusting the gain of the programmable gain amplifier to bring the full capacity related data to within a second predetermined portion of the dynamic range of the A/D converter.

4. The method of claim 3, wherein:

the first predetermined portion is within seven and eight percent of the dynamic range of the A/D converter, and

the second predetermined portion is within forty and eighty percent of the dynamic range of the A/D converter.