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out).
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
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