Rice Lake TradeRoute HL Series - M2000 Scale - Manual (Page 20)

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1. Before the scale can be calibrated, all load cells must be balanced and
responding to loading equally by adjusting the balance trimmers. If you
have a weigh center, the balance trimmers are located on the main
circuit board, inside the control panel. If you do not have a weigh center,
your balance trimmers will be located inside a junction box on the scale.
All trimmers are initially set to 2-Ohm resistance. Use the following
procedure to balance the load cells.
2. Use proper balancing weights to ensure good balancing. Use a minimum
of ¼ of the net capacity of the scale for balancing. I.e. for a 10,000-lb net
capacity, use at least 2500 lbs. for balancing. However, be careful not to
exceed the capacity of the individual load cells.
3. Activate the scale so that the platform is live. Load weights to the full
capacity of the scale: then, unload all the weights. This process
“exercises” the load cells.
4. Press the zero key to obtain a good center of zero. Load one cell by
placing the balancing weights on that corner of the scale (inside the
loading area). Keep the weights as close to the cell as possible directly
above the cell being preferred. Record the weight on the M2000.
5. Repeat step 4 for the other cells with the same procedure (remembering
to press the zero key to obtain a good center of zero). All the readings
should be within approximately one percent (1%) of each other. If the
readings are significantly farther apart, you may not be able to balance
your system. Contact Rice Lake Weighing Systems for technical
assistance.
6. Pick the lowest reading and adjust the other cells down to this value with
the trimmers inside the control box. To adjust a cell use the following
procedure:
7. With no test weights on the scale, press the zero key to obtain a good
center of zero
8. Load the balancing weight over the cell to be adjusted.
9. If you have to adjust the cell by one or two graduations, simply turn the
trimmer clockwise to reduce the displayed reading to the desired
reading. Make sure you are adjusting the appropriate trimmer. Typical
load cell numbering conventions are shown below.
10. If you have to adjust the cell by more than one or two graduations, the
system may undergo a zero shift during the adjustment. Adjust the cell
(by turning the trimmer clockwise) to one graduation LOWER than the
desired value. Remove the weights and check the zero. Re-zero the scale
and repeat the process until the desired reading is obtained.