LINK Systems System 1100 Tonnage Monitor - Manual (Page 85)

7-1
If the "rate of change" automatic zeroing method (no cam switch
used for zeroing) is used, it is necessary to verify that strains
induced in the machine frame due to mechanical noise, such as
engagement of clutches or brakes or gear "slap" do not exceed the
factory set zeroing threshold of 5% of rated channel tonnage.
1) Select a die from the group of dies used in the machine with
one of the heaviest upper die weights. Install the die in the
machine and adjust the machine shut height so that the dies
don't close at the bottom of the stroke. The purpose of
installing this die is to make sure that acceleration and
deceleration forces when a stroke begins and ends will produce
the maximum strains in the machine frame that will be
experienced in actual production operations. The heavier the
upper die, or other tooling attached to the slide, the greater
the acceleration and deceleration forces due to clutch or
brake engagement or gear slap.
2) Set the low setpoint limits of the System 1100 to zero (0).
The high setpoint limits should be set to at least 50% of
rated machine tonnage capacity.
3) Make single strokes of the machine and observe the System 1100
tonnage displays. The tonnage displays will constantly read
zero if acceleration and deceleration forces at the beginning
and end of the stroke do not strain the machine frame enough
to exceed the 5% zeroing threshold.
If the tonnage displays remain zero throughout several single
strokes, proceed to step 5 of this procedure.
If the tonnage displays change from zero to indicate a number
other than zero at the start of the stroke only, and retains
this same number at the completion of the stroke, the
acceleration forces at the beginning of the stroke are
straining the frame enough that the 5% zeroing threshold is
exceeded. In actual production operations the tooling force
at the bottom of the stroke will replace the reading caused by
acceleration forces and retain the actual tooling tonnage at
the end of the stroke. Proceed to step 5 of these procedures.
If the tonnage displays change to indicate a number at the end
of the stroke, deceleration forces caused by braking are
causing strains in the machine frame that exceed the 5%
Section 7. Zero Circuit Checkout After Calibration