4) Remove the simulator and attach the load cell. Remove the load from
the cell while leaving the dead load attached. If "gr OL" is displayed,
note the "NEG" annunciator.
a) If the "NEG" annunciator is on, the overflow is negative,
turn R10 counter clockwise until the overload clears. If the
annunciator is off, turn R10 clockwise until the overload is
cleared and the raw counts fall between -19,000 counts and
-10,000 counts.
b) If it is not possible to clear a positive overflow, begin
increasing the negative zero shift by adding JU7 and JU8
(as shown in table 2). After inserting a jumper, adjust R10
across it's full range. Repeat this sequence until the no load
raw counts lie between -19,000 counts and -10,000 counts.
Remove power to avoid damaging the scale when inserting
and removing jumpers. Go to step 6.
5) Adjust R10 until the no load raw counts lie between -19,000 counts and
-10,000 counts. If this is not possible, adjust R10 for the most negative
reading.
6) Place the calibration weight on the scale. Record the raw counts
reading. Calculate the span by subtracting the no load counts from the
full load counts. If half capacity, quarter capacity or 10% capacity
calibration is being used, multiply the span by factors of two, four or ten
respectively. If the scale goes into overload, begin increasing the
negative zero shift by adding JU7 and JU8 (as shown in table 2) Repeat
steps 4 and 5 after each jumper change. In cases where the span is
greater than 30,000 counts, it may be necessary to adjust the no load
counts to about -18,700 counts.
7) Using the calculated span from above, refer to table 3. Select and
install the correct combination of JU9, JU10 and JU11.
8) Verify that the no load raw counts are between -19,000 counts and
-10,000 counts. It may be necessary to readjust the zero point by
reducing the "zero shift" percentage or by adjusting R10.
9) Verify that the no load to full load span is greater than 21,000 counts
(greater than 24,000 counts is preferred).
10) Once the zero and span are set, calibrate the scale using the normal
calibration procedure.
26
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