Specifications

Scale Operations 23
2. Place another tare weight on the platform and press the TARE key again. This will add the two tare
weights together (Tare Addition).
3. Tare weights can be subtracted individually by removing one from the platform and pressing the TARE
key again. To clear all the tare weights and return to the Weighing Mode, remove all the tare weights and
press the TARE key. The Net annunicator will no longer be lit.
5.4.4 Tare Override
For instructions on how to temporarily override a tare that is called up with an Item Code, please see
Section 5.9.4.
5.5 Entering Unit Weights
Entering unit weights can be done either by sampling, as presented in Section 5.5.1, or by key entry as described
in Section 5.5.2.
NOTES: SPC 05 - EXTENT OF INSUFFICIENT SAMPLES controls unit weight sampling. The default setting for the SPC is 00:
0.1 percent.
SPC 14, Bit 3 - CLEAR UNIT WEIGHT WHEN SWAP SCALE sets whether the unit weight determined by sampling is
automatically transferred from Scale 1 to Scale 2 or is cleared when you transfer scales. SPC 14, Bit 1 - AUTO SCALE
SWITCHING, sets . When you have a procedure that involves sampling an item’s unit weight on the DC-788’s built-in
platform and then want to go immediately to weighing and counting boxes or bins on a floor scale or other external
scale, set SPC 14 to 1: YES. If the external Scale 2 is not necessarily going to be used for weighing the same item as is
being sampled on Scale 1, set SPC 14 to 0: NO.
SPC 03 - UNIT WEIGHT BASE PER 1000PCS OR 1PCS controls whether the unit weight is displayed per 1000 pieces
or per 1 piece. The default settings for this SPC is 0: 1000 pieces.
(For further instructions on how to set the specifications, see Section 3.1.1)
Unit Weight per 1000 Pieces vs. Unit Weight per 1 Piece
The scale’s internal microprocessor calculates unit weights to 7 or 8 decimal places. However, the scale display
generally can only show Unit Weight to 5 characters. If this Unit Weight is recorded from the scale display and
entered by key entry, this can introduce errors in the Unit Weight and consequently in the counts. This error
increases as the Unit Weight of the parts being counted decreases.
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.
When might you want to use unit weight per 1 piece? Generally in one of two cases:
1. If you are working with other existing systems or procedures that are already set up to record unit weight
per piece (inventory systems, labeling requirements, etc).
2. If the unit weight or your pieces is more than 100 lbs, as in the case of some castings, engine parts and
the like. When the unit weight is over 100 lbs, the number of digits in the scale’s Quantity display will
not be able to fully display counts of more than 100 pieces.
5.5.1 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 PCS 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 PCS key.