LINK Systems 5100-8 Tonnage & Analog Signal Monitor - Manual (Page 69)

Doc #: L-802-1110 Page 67 Rev. 02
16) Reduce the load gradually, and verify that the tonnages displayed by the tonnage monitor
"track" within one or two percent of those of displayed on the load cells. Failure of this
indicates a non-linearity which could be due to incorrect strain gauge location, improper strain
gauge mounting, or incorrect tie rod tension (in frames of this construction).
17) Press the EXIT softkey and return to the tonnage monitor menu.
18) Remove the load cells and associated "stack" elements from the machine.
Calibration
is complete.
7.2 Replacing System 1000/1100 Tonnage Monitors
If the 5100-8 Tonnage & Analog Signal Monitor is replacing a System 1000 or System 1100 Tonnage
Monitor that is already installed on the machine and calibrated, the calibration numbers from the System
1000/1100 can be transferred to the new tonnage monitor. Each System 1000/1100 calibration number
should be multiplied by 1.11 and entered in the System 5100 Tonnage Monitor Calibration screen (see
section 4.5 on page 47). For instance, if the channel 1 calibration number on a System 1100 tonnage
monitor is 200, then the calibration number for channel 1 of the 5100-8 tonnage monitor would be 222
(200 X 1.11 = 222).
7.3 Replacing System 5000 Tonnage Monitors
If the 5100-8 Tonnage & Analog Signal Monitor is replacing a System 5000 Tonnage Monitor that is
already installed on the machine and calibrated, the calibration numbers from the System 5000 can be
transferred to the new tonnage monitor. The calibration numbers for the System 5000 and 5100-8
Tonnage Monitors are the same and no adjustment is necessary.
7.4 Incorrect Tie Rod Tension
Straight side machines of tie rod construction are designed for tie rods to be in tension such that the bed
and crown or the machine are held to the uprights (columns) with a force of from 150% to 200% of rated
machine tonnage. The tension forces in the tie rods produce equal compression forces in the uprights.
When strain gauges are mounted on uprights, the tonnage exerted by the machine tooling stretches
(strains) the tie rod by an amount proportional to load and releases the compressive forces in the
uprights proportional to the load. If the tension on a tie rod places a compressive force on the upright
that is less than the force released by the load, all compressive force will be removed from the upright (it
will have stretched back out to its original length), and the signal from the strain gauge on the upright
will no longer be proportional to load.
A loose tie rod condition can be detected during calibration of a straight side machine when strain
gauges are mounted at approximately the same location on the uprights. If, at rated tonnage, the
calibration number associated with one or more channels must be much higher than the other channels in
order to produce equal tonnage readings, improper tension in the tie rod may exist. To determine if tie
rod tension is the actual cause, reduce the load on the load cells during calibration until the sum of the
load cell tonnages is equal to about 1/4 of rated machine tonnage, while making sure that approximately