LINK Systems OmniLink II Press Automation Control - Manual (Page 89)

August 30, 2002 Manual Version 1.0 5.6
The Intellistop angle is automatically computed by the OmniLink based on the angle of travel during
top stopping. The angle labeled Top Stop Angle in Figure 5.3, is the angle at which a stop signal
must be given which will result in the press stopping on top (0
0 ). The angular distance traveled in
top stopping is also used to compute the Intellistop angle. For a variable speed press, both the top
stop and the Intellistop angle are automatically advanced to compensate for the increased
stopping distance at higher speeds as shown in Figure 3.5. The mechanics of stopping in the
downstroke are somewhat different than stopping at top of stroke. Also gradual clutch and brake
wear will increase stopping distance. For this reason, it is advisable to subtract about 10
0 from the
critical angle as determined in the preceding item 1 of this discussion to allow for these factors.
Another aid to determine the angular stopping distance, is the Stopping Degrees display shown
below Critical Angle on the operator terminal display. This angular stopping distance is
measured and displayed every time the press stops regardless of where in the press stroke the stop
occurs. You can stop the press such that it stops in the downstroke and read the actual stopping
distance from the display. Of course, this is also a great aid in determining whether a regular Top
Stop or Cycle Stop setting should be chosen for cyclic sensor channels where the fault will occur
within a known timing window.
Thus, as shown in Figure 5.3, if Intellistop is chosen for a sensor channel, the order of stopping will be
as follows.
• If a sensor fault occurs after the Intellistop Angle but before the Top Stop Angle, a Top Stop will
result.
• If a sensor fault occurs after the Top Stop Angle but before the Intellistop Angle a Cycle Stop will
result.
NOTE! Intellistop will revert to Top Stop if the angular stopping distance of the press exceeds
180
0 .
It is not necessary to determine the Critical Angle each time the die is used in the press. Once the
Intellistop angle is initially determined, it will be stored as part of the job by the OmniLink and recalled
with the job. As stopping distance can gradually increase with brake wear and clutch wear, it may be
necessary to adjust the clutch and brake periodically to maintain stopping at or before the critical angle.
Section 5.2.4 Stopping Degrees
Each time a stop signal is applied to press stroking, the press crank or eccentric shaft travels for period
of time and through an angular distance before stopping. The Stopping Degrees displayed is the angular
stopping distance traveled the last time the press stopped. The stopping degrees are measured and
displayed each time the press stops regardless of where the press stops in the stroke as long as the
clutch has been engaged long enough to cause a crankshaft speed above the minimum speed
threshold configured for the system. The display may not change when inching the press so quickly
that minimum speed is not attained. Stopping Degrees can be extremely useful in determining whether a
Top Stop or Cycle Stop setting should be made for a sensor channel when a fault is detected.