Specifications

Scale Operations 21
5.0 Scale Operations
The following sections contain detailed operator instructions for the DC-530 counting scale (see Figure 5-1).
Included are instructions on how to switch between scale platforms, how to enter tare weights, how to enter unit
weights, and how to perform counting operations both in the regular Counting Mode and the TEP (Teraoka Error
Prediction) Mode.
Figure 5-1. DC-788 Counting Scale
5.1 Counting Scale Accuracy and the TEP (Teraoka Error Prediction) Mode
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, 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 this kind of application, a scale like the DC-530 with an extra scale channel is
often 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 can be accomplished by:
1. Isolating the sample used to calculate the unit weight and use the same sample to re-check the scale.
2. Recalculating the unit weight from lot-to-lot of parts. Parts manufactured on one machine may vary
slightly from another machine relative to weight.
3. Tightening the manufacturing tolerances on the parts reduces piece weight variations and increases count
accuracy.
Parts can vary greatly in their value. With parts of lesser value per piece, the extra sampling and time involved in
trying to achieve 100% accuracy as opposed to 99.5% may not be cost-effective. However, with high value
items 100% accuracy is vital. To address this need, the DC-530 provides you with two counting modes: Regular
Counting Mode and TEP (Teraoka Error Prediction) Mode. Regular Counting Mode offers you the same
ultra-high-precision that all DIGI products are noted for. When you have high-value items, TEP Mode walks you
through a more extensive sampling process from which the scale calculates and displays the number of parts that
can be counted at a time with no counting error.