LINK Systems OmniLink II Press Automation Control - Manual (Page 147)

August 30, 2002 Manual Version 1.0 7.10
example, a feed roll pilot release is intended to release the feed rolls from the material, so that the die
pilots can pick up the material and position it correctly. The pilot release cannot release too soon or the
material may fall back out of the die. The pilot release cannot release too late or it will be holding on to
the material as the die pilots try to position the material. The pilot release takes a certain amount of time
to actually release the material. After the pilot release solenoid valve receives its electrical signal, the
valve must shift to let air into the pilot release. The pilot release air pressure must built up to a level that
overcomes the pilot springs before the material is released. The total time between the turn on of the
release solenoid valve and the actual lifting of the pilots is the reaction time.
Without speed advanced outputs, it may not be possible to correctly set the turn on angle for the control
of the pilot release for all press speeds. As the press speed increases, the die pilot pins approach the
material faster. If the turn on of the pilot release solenoid valve is correct at slow press speed, it may not
be correct at high press speed. The reaction time of the pilot release does not change with speed. The
time between the turn on angle and the required material release angle gets smaller as press speed
increases. The pilot release may not be able to release the material before the die pilots pick up the
material as press speed increases.
Speed advance will compensate for the increase in press speed. The speed advance is programmed with
the desired angle for the action to be accomplished. The speed advance is also programmed with the
reaction time. The speed advance will increase the angle based upon the machine speed and the device
reaction time. In the case of the pilot release, the turn on angle will be increased as the press speed
increases. If programmed properly, the amount of increase will be such that the pilot roll release will
release the material at the same press position, just as the die pilot pins pick up the material for all press
speeds.
The availability of speed advance is configurable. If this feature is not required, it can be removed
during the PLS configuration. See Section 7.6.2.
Section 7.6 Configuration
In order for the Programmable Limit Switch to be recognized by the OmniLink II Press Automation
Control, a Device Configuration must be performed. This process is described in Section 4.1.
After configuring the system to recognize the Programmable Limit Switch module(s), the Limit Switch
Screen can be accessed on the OmniLink II operator Terminal. The Limit Switch Screen can be entered
from the Main Menu by selecting the LIMIT SWITCH softkey. The Limit Switch Screen is shown in
Figure 7.4.