LINK Systems 5100-8 Tonnage & Analog Signal Monitor - Manual (Page 67)

Doc #: L-802-1110 Page 65 Rev. 02
cells as necessary to reduce the gap between slide and bolster so that the "stack" of load cells
and parallels can be contacted at the bottom of the machine stroke.
It is recommended that steel plates at least one inch thick and of at least 2 inches greater lateral
dimension than the load cell contact surfaces be placed both under and over the load cell to
help distribute the load and avoid load cell impressions in the slide or bolster material. All
plates or parallels should be symmetrically placed relative to the centerline of the load cells,
and plates and parallels used for each load cell stack should be similar in dimension to those
used in other stacks.
On mechanical power presses with shut height adjustments, the stack height should be greater
than the minimum shut height, and the machine shut height must be adjusted so that clearance
between the machine slide and the load cell stack(s) is provided.
WARNING: If the load cell(s) stack height is greater than the machine shut height, as
adjusted, cycling the machine may result in severe damage to the machine
and to load cells!
9) Check to assure that the load cell stack(s) are correctly located and that the machine shut height
or other bottom of stroke adjustment provides clearance between the ram or slide and the load
cell stack(s) as per the instructions of the previous step of this calibration procedure.
10) Turn on the power to the machine and bypass the tonnage monitor (see section 3.2.4 on page
22). Return the slide to the top of stroke position.
11) Make single strokes of the machine, adjusting the shut height or other bottom of stroke
adjustments downward 0.002" to 0.004" between successive strokes until any of the load
cell(s) give a reading, indicating that contact is being made with one or more load cell stacks.
12) If a single load cell is used for calibration, continue to single stroke the machine and adjust
shut height or other bottom of stroke adjustment until the rated capacity of the load cell or the
machine, whichever is less, is reached.
The rated tonnage capacity of the load cell should be at least 50% of the rated tonnage capacity
of the machine being calibrated. Adjustment distance should be restricted to less than 0.001"
between strokes as rated machine tonnage is approached.
If two or more load cells are used for calibration, adjust the shut height or other bottom of
stroke adjustment until about 20% of rated machine tonnage capacity is displayed on the total
of the load cell readings. If load cell tonnages are not equal, add shim stock to the stack of
load cells with lower readings. Make a single stroke of the machine and observe the new
tonnage readings of each load cell channel. Repeat this process until all load cell readings are
equal to within 2%.