Scale-Tronix 6702 - 4.72 Calibration Procedure (Without Dip Switches)

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4.72 GALIBRATION PROCEDURE (WITHOUT
DIP SWITCHES)
This procedure is similar to section 4.71 with
the exception of how to enter the calibration mode.
Dip switches have been eliminated; however, the
calibration procedure still uses the calibration
potentiometer on the main printed circuit board.
Enter
the "calibration mode” by following exactly the
procedure outlined below:
1. Be sure scale is off.
2. Press and hold in the “RE WEIGH"
pushbutton.
3. While pressing the "RE WEIGH” pushbutton
press and release the "ON" pushbutton. On
scales that do not employ the "ON"
pushbutton, such as the model 5102, turn the
power rocker switch on while pressing "RE
WEIGH”.
4. NOTE: The "ST pushbutton is a special
hidden programming and test pushbutton
located under the SCALE-TRONIX® logo
(ST) on the left side of the front panel
between the "ZERO" and "RE CALL"
pushbuttons.
After the scale displays the test pattern of
"888888" release the "RE WEIGH" button
and press the "ST" pushbutton five (5) times.
This will cause the readout to enter the
calibration mode, The display will indicate
"CAL".
5 Press the "ST" pushbutton once more; the
display will indicate “A-d". This indicates the
start of the "raw" analog-to-digital converter
data being inputted to the micra processor.
6. Press the "ST" pushbutton one more time.
The number displayed is now the raw analog
to digital data.
7. The automatic turn-off timer has also been
programmed for an extended “on period to
give you time to calibrate the scale. This time
period is three minutes. The scale may be
turned off before this time period by simply
pressing and_ holding the “ON" pushbutton.
Hold it in for several seconds until the power
shuts off. If additional time is needed to
complete the calibratian procedure, press the
"ON" pushbutton briefly. This will reset the
timer for an additional three minutes.
Now that you are in the calibration mode the
calibration procedure is the same as in section 4.71,
That procedure is repeated here for your convenience.
The readout is displaying a number, which represents
the zero offset value of the platform and load cell
transducers, in tenths of pounds (0.1 pound). Note
and record this value. (Even though your scale may
be "kilograms onty” in operation, pounds are used
internally because of their finer resolution.) Units
conversion is as follows:
1.0 Kilogram = 2.2 (2.2046) pounds
5.0 Kilograms = 5.5 (5.51) pounds
10.0 Kilograms = 22.0 (22.046) pounds.
25.0 Kilograms = 55.1 (55.116) pounds.
50.0 Kilograms = 110.2 (110.231) pounds.
75.0 Kilograms = 165.3 (185.346) pounds.
100 Kilograms = 220.4 (220.46) pounds.
Add the specified test weight to the platform. Note the
new number displayed. - Subtract the original zero
offset value from this new number to obtain the scale's
displayed value of the calibration weight.
Note: Early versions of the software did not display the
decimal point in the a-d calibration mode, i.e.: 11.7
pounds is displayed as "117".
(Example: The zero offset value is 711.7"
(representing 11.7 pounds). Adding the specified
three 25 kilogram test weights (equivalent fo 165.3
pounds) to the platform produces a reading of "177.1".
The difference is 177.1-11.7 = 165.4 (equivalent to
185.4 pounds). This would indicate the calibration is
0.1 pound "high".
Using the specified three 25 kilogram test weights a
difference of 165.3 +/- 0.1 pound should be obtained.
lf necessary adjust potentiometer P1 (span adj.) on
the instrument board until the correct value is
30 5002, 5102, 5602, 6002, 6102, 6202, 6502, 6702