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DC-530 Operation Manual
5.0
Scale Operations
The following sections contain detailed operator instructions for the DC-530 counting scale. Included are
instructions on how to enter tare weights, accumulate tare weights, establish unit weights, accumulate item
counts, perform negative counting, and count parts in both Normal Counting Mode and TEP (Teraoka Error
Prediction) Mode.
When performing all weighing and counting operations, the scale must be stable before it will accept an entry.
The scale will indicate that the weight reading or count is stable by illuminating the Stable indicator lamp. If you
press a function key when the scale is not stable you will hear a double beep indicating that the function cannot
be performed yet. Once the Stable indicator lamp is lit, then perform the function.
Figure 5-1. DC-530 Counting Scale
5.1
Factors Affecting Counting Scale Accuracy
Counting scale accuracy is primarily determined by the following factors:
•
Sample size (number of pieces)
•
Total sample size as a percentage of full scale capacity
•
Piece-to-piece weight variation
As a general rule, when determining sample size of fairly uniform pieces, the larger the sample size the greater
the total sample weight and therefore the better the counting accuracy. Selecting the smallest capacity scale that
can obtain the highest counting resolution should be considered, but should not sacrifice the capacity required for
the heaviest container of parts. For some applications, a dual-platform scale utilizing the DC-530’s optional
capability to connect a second scale may be the best selection.
There is a direct relationship between piece-to-piece weight variation (non-uniformity) and counting accuracy
.
Therefore, elimination of the piece-to-piece weight variations will greatly improve accuracy. This can be
accomplished by:
•
Isolating the sample used to calculate the unit weight and use the same sample to re-check the scale.
•
Recalculating the unit weight from lot to lot of parts. Parts manufactured on one machine may vary
slightly from another machine relative to weight.
•
Tightening the manufacturing tolerances on the parts reduces piece weight variations and increases
count accuracy.
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