Field Inspection Manual — Non-Automatic Weighing Devices
Part 3, Section 19: STP-19: Motion Detection Test
Sections 45 of the Non Automatic Weighing Devices Specifications.
Electronic devices must have motion detection capability to prevent the device from zeroing (semi-automatic zero) or taring (platter or keyboard tare) a part of the load when the semi-automatic zero or tare key is activated while a load is added, changed or removed from the platter.
Electronic devices equipped with a printer (or that have connections for a printer) must have motion detection capability to prevent the device from printing values before the weight display has stabilized. This reduces the possibility of recording incorrect weight values.
This test is to determine if printing, zeroing, or the entry of a tare is inhibited when motion is detected.
- Place a load within the weighing range on the platter and allow time for the indication to stabilize.
- Induce a motion to the scale indications to a peak magnitude of at least 10 e (amplitude);
- While disturbing the weight indication, activate the SAZSM and allow the oscillations to settle out. The scale may eventually zero the load or may reject the command.
- While disturbing the load, attempt to activate the tare button (platter tare). The scale may eventually tare the load on the platter, or reject the command.
- While disturbing the load, attempt to print. The scale may print a weight or reject the command.
- Repeat the test two or three times for small loads ( near zero) and loads near capacity.
Interpretation of Results
The device complies with the requirements if zeroing, taring or printing the load on the platter is prevented, or is within 1 e (verification scale interval) for scales that have a maximum capacity of up to 2 000 kg (5 000 lb); or 3 e (verification scale intervals) for scales of more than 2 000 kg (5 000 lb). Printed and displayed weight values must be within the prescribed limits of error.
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