Laboratory manual for the evaluation of non-automatic weighing devices

LG-3.09 DC Voltage variation

Table of contents


Sections 9, 10, 11 and 27 of the Specifications Relating to Non Automatic Weighing Devices (1998)


This test is performed on any complete electronic devices or major electronic components that operate from a DC power source (Batteries or other DC sources, but not through an AC/DC adapter). Self-powered weighing elements will be submitted to this test. Voltage variations are susceptible to occur during the normal use of devices. The purpose of this test is to ensure that voltage variations do not adversely affect the device performance and normal operating characteristics. DC power operated devices must continue to operate normally despite of a power reduction to the point where no weight indication is provided and power increase by 10% of the nominal value.



  1. Let the Power Supply and the DUT warm up for the minimum time recommended by the manufacturer.
  2. Decrease the voltage until the device ceases to provide a weight indication. Increase the voltage until the device resumes the indication; re-zero.
  3. Perform an increasing and decreasing test and record the results.
  4. Activate the device functions to ensure they operate normally (tare, printing, motion detection, etc.)
  5. Record the following data:
    1. time,
    2. temperature,
    3. relative humidity,
    4. voltage,
    5. loads,
    6. indications,
    7. errors, and
    8. note any malfunctions of the features.
  6. Increase the power supply voltage up to 10% above the device nominal voltage; re-zero and repeat steps 3, 4 and 5

Note: It may be necessary to increase the voltage beyond the limit point of display, and then decrease the voltage in order to be able to reach the lowest voltage at which an indication is provided.

Some devices have an extended voltage range, for instance from 12 to 72 DC volts. In such a case, the device will be tested at the lowest voltage where a weight indication is provided and 10% above the high limit of the voltage range.

Interpretation of results

The DUT is deemed to have met the requirements if during the voltage variations the device:


Rev. 1 (March 2010)
  • AZSM renamed to AZTM
  • Formatting change
  • Removed requirement for an increasing/decreasing test at nominal voltage
Date modified: