Laboratory manual for the evaluation of non-automatic weighing devices
LG-3.08 AC Voltage variation
Table of contents
- Maximum and minimum voltage specified
- Interpretation of results
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 powered from an AC source. 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 affect the device performance.
- AZT may be in operation during the tests. It must be set to the lowest value; if zero is the lowest selectable value, it will be set to zero. The amount that the AZT may track at once may not be set to a value larger than 0.6d which is the maximum value allowed by the Specifications.
- If the IZSM range does not exceed 20% of Max, tests will be performed once with the IZSM set at the upper limit of its range.
Note: In the case of a multi-range device, it is 20% of Max of the lowest range; in the case of a multi-interval device, it is 20% of max of the first range.
- If the IZSM range exceeds 20% of Max, tests will be performed twice: a first series of tests using the lightest platter provided by the applicant and the second series with the IZSM set to the upper limit of its range.
- The weighing device must be leveled to its reference position.
- The device must be set for the maximum capacity and smallest verification scale interval for which the approval is sought.
- If so equipped, the "enhance resolution feature" of the device will be used during the tests. If this feature is not available, use the small weight method to determine the device errors before rounding.
- This test is performed at ambient temperature (≈ 20°C); or at the mid point of the temperature range if significantly different from 20°C; and ≈ 50% RH.
- Power source must be stable to within ±2%
- Let the Power Supply and the DUT warm up for the minimum time recommended by the manufacturer.
- Decrease the voltage to the minimum voltage specified.
- Perform an increasing and decreasing test and record the results.
- Activate the device functions to ensure they operate normally (tare, print, motion detection, etc.)
- Record the following data:
- relative humidity,
- errors, and
- note any malfunctions of the features.
- Increase the power supply voltage to the maximum voltage specified; repeat steps 3, 4 and 5.
Maximum and minimum voltage specified
- If the nominal voltage is not indicated on the marking plate, 117 volts or 225 volts, as the case may be, is deemed to be the nominal voltage. Then, the minimum and maximum voltage are 100 volts or 191 volts (-15%) and 129 volts or 247.5 volts (+10%) respectively.
- If the marking plate indicates a nominal voltage other than 117 volts, the indicated voltage will be considered as the nominal voltage. The minimum and maximum voltage will be calculated from the nominal voltage indicated on the plate.
- If a voltage range is indicated ( i.e. 100 volts to 130 volts), the test will be performed at Vmin -15% and again at Vmax +10%
- If the device ceases to indicate weight values while the voltage is well within the -15% / +10% range limits, the tests will be performed at the limits of indication.
Interpretation of results
The DUT is deemed to have met the requirements if, during the voltage variations, the device:
- operates within the prescribed limits of error and all the functions operate normally; or
- ceases to display weight and price values and prevents the transmission and storage of data.
- Rev. 1 (March 2010)
- AZSM renamed to AZT
- Formatting change
- Procedure altered to change specified voltages with devices that operate over a range of voltages
- Removed requirement for an increasing/decreasing test at nominal voltage
- Date modified: