Hardy ANY-WEIGH Bench Scales - Manual (Page 34)

Any-Weigh™ Series Bench Scales
6-6
Step 6. Adjust the SPAN for 20 mA (2 V) for full-
scale weight. For less than full-scale
weight, perform the following steps:
1. Divide: calibration weight/full-
scale weight = (F)raction of full
scale.
2. Multiply: (F)(16 mA) = 1, the cur-
rent caused by the calibration
weight.
3. Add: 1 + 4 mA = Calibration Cur-
rent, 1c.
4. Adjust SPAN to produce the Cali-
bration Current, 1c, in the output/
power loop.
• For Example:
Calibration Weight = 750 pounds
Full Scale Capacity = 1000 pounds
Adjust SPAN for:
(750/1000)(16 mA) + 4 mA = 1c
(0.75)(16 mA) + 4 mA = 1c
12 mA + 4 mA = 1c
16 mA = 1c
Step 7. Remove the calibration weight and
recheck to see if the zero reading is still 4
mA (0.4 V). Adjust the Fine control if nec-
essary.
Step 8. Place the calibration weight on the scale
again and recheck to see if the calibration
reading is correct.
• Adjust the SPAN if necessary.
Step 9. Repeat Steps 7 & 8 until no further adjust-
ment is necessary to keep both measure-
ments within the system tolerances.
Step 10. Calibration is complete. The resistor
inserted for voltage checks may now be