Scale Operations
21
Example: A sample of 10 zener diodes is placed on the scale. The Unit Weight is computed by the scale to be
0.0006536 lbs. However, the scale has a 5 character display for Unit Weight so the scale can only display.0065 as
the Unit Weight. If this Unit Weight were recorded and keyboard entered in future counting operations, the
resulting error would be: 00065 =.55%
.0006536
On the other hand, with entry of the Unit Weight as “weight per 1000 pieces” the decimal place is, in effect,
moved three places to the right, allowing 3 more decimal places of accuracy. In this example, the entry would be
made as 0.6536 per 1000 pieces, eliminating the error.
As a practical note, entering unit weights per 1000 pieces also lessens the chances of entering the wrong number
of zeros when keying in weights with many leading zeros. Misentry of unit weights is a common cause of
inaccurate counting.
5.3.1
Unit Weight Operation by Sampling
Unit weight operation by sampling is accomplished by placing a 10 piece sample on the scale and then pressing
the
PIECES
key. The scale calculates a unit weight based on the capacity of the scale compared to the weight of
the sample. If you wish to use a sample of more than 10 pieces, place the sample on the scale, then input the
sample size before pressing the
PIECES
key.
If the sample size is insufficient to give an accurate unit weight, no unit weight will be displayed, the
INSUFF
lamp will be illuminated. To get to an adequate sample size :
•
You can add pieces to the sample (keeping track of how many you add) until the
INSUFF
lamp goes
out Key in the new total sample quantity and press the
PIECES
key. The scale will compute and
display the unit weight.
•
If you press the
PIECES
key while the
INSUFF
lamp is lit, the scale will show the word
ADD
in the
Unit Weight
display and a number of pieces to add in the
Quantity
display..
•
Add exactly the suggested number of pieces shown to bring the sample up a weight that allows
calculation of a more accurate unit weight. The
Quantity
display will go down to zero, then press the
PIECES
key. The scale will recompute and display the total weight in the
Weight
display, the unit
weight per thousand in the
Unit Weight
display, and the number of pieces in the
Quantity
display.
You can ignore or override the
INSUFF
indicator by pressing the
PIECES
key again without adding more pieces
to the sample. However, it may affect counting accuracy to use a Unit Weight calculated on the basis of an
insufficient sample. If you do press the
PIECES
key again, the scale will compute and display the unit weight
based on the original sample you gave it.
If the
RECOMP
indicator is lit, the accuracy of the unit weight computation can be improved by adding
approximately double the number of pieces currently on the scale and pressing the
PIECES
key again. The scale
will flash as it recomputes the unit weight, after which it will display the new Unit Weight.
5.3.2
Unit Weight Operation by Key Entry
Unit weight operation by key entry is accomplished by using the numeric keypad to enter the known value of the
unit weight and then pressing the
UNIT WEIGHT
key. An example of unit weight operation by key entry is
shown below:
1. With the display in the weighing mode, enter the known unit weight using the keyboard, for example,
5.2578
.
2. Press
UNIT WEIGHT
key to enter the unit weight.
3. Press the
CLEAR
key to clear the Unit Weight.
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