LINK Systems OmniLink 5000 - Manual (Page 72)

April 17, 2000 Man ual Revisio n 1.0
8.4
Caution! 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!
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.
h) Check to assure that load cell stacks are correctly located and that machine shut height of other
bottom of stroke adjustment provides clearance between ram or slide and load cell stack(s) as per the
instructions of step “g” of this calibration procedure.
i) Turn on the power to the machine and bypass (see Section 4.2.4) the OmniLink 5000 Tonnage
Monitor Module. Return the slide to the top of stroke position.
j) Make single strokes of the machine, adjusting the shut height or other bottom of stroke adjustments
downward to lower the machine slide or ram from 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.
k) 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%.
When load cell tonnages are equalized, again repeat the cycle of single stroking the machine with
shut height or other bottom of stroke adjustment between strokes and continue to observe the
tonnage on each load cell It may be necessary to re-shim certain load cell stacks to equalize tonnage
on all load cells as rated tonnage capacity of the machine is neared. Rated machine capacity of the
machine is reached when individual tonnage on load cells equals the rated machine tonnage divided
by the number of load cells used to calibrate the machine. For example, if four (4) load cells are
used to calibrate a 200 ton mechanical power press, the press is loaded to capacity when each of the
four load cells is loaded to 50 tons. When rated machine tonnage, or a lesser tonnage at which the
machine is to be calibrated is reached, lock shut height adjustments, etc., and proceed to step “l”.
Do not exceed rated tonnage capacity of the machine or load cells during the calibration process by
more than five or ten percent.