LINK Systems OmniLink II Press Automation Control - Manual (Page 138)

August 30, 2002 Manual Version 1.0 7.1
Section 7 Programmable Limit Switch (PLS)
The Programmable Limit Switch is an optional addition to the OmniLink II Press Automation Control.
This unit provides electrical outputs that are related to machine position. The outputs can be used to
control solenoid valves and to provide sequencing signals to feed and transfer systems.
Section 7.1 Features
The programmable limit switch system consists of PLS/Logic Modules (Model 5100-5B) and an output
relay boards. The PLS/Logic Module contains the control logic and power supply necessary to control
and power the output relay boards. The output relay boards provide the necessary electromechanical or
solid state relays. Each PLS/Logic module can control and power two output relay boards. Each output
relay board has eight relays. The OmniLink II Press Automation Control can have a maximum of four
PLS output boards. Therefore 8, 16, 24 or 32 PLS channels can be provided.
The output relays can be electromechanical relays or solid state AC relays. The electromechanical
relays are plug-in for individual replacement. The solid state board has provisions for eight plug-in solid
state relays. The solid state relays can be either AC or DC. A solid state relay board can contain any
combination of AC or DC relays totaling to eight.
There are five possible modes of operation for each of the thirty-two PLS channels. These modes are
Always Off, Always On, Normal, Timed Off, and Toggle. See Section 7.5 for details of each mode.
Some modes can be programmed for Counted Outputs. A channel programmed for counted output will
not have its PLS function occur every stroke. Instead it will cycle its output relay after the programmed
number of strokes. For example a channel set to the Normal mode with a Counted Output set to five
strokes, will turn its output relay on and off every fifth stoke. The output relay will remain off during
the remaining four strokes of the five stroke cycle.
Turn on and/or turn off angular positions can also be independently speed advanced. The speed
advance, if properly programmed, will cause the PLS outputs to turn on or turn off earlier in the stroke
to compensate for the greater distance the machine crankshaft will turn at higher speeds in the given
reaction time of the automation device. This is particularly useful for PLS sequenced feed roll release
associated with the pilot function. If Normal Mode is used, both the on angle and the off angle can
independently speed advanced.
Section 7.2 Specifications
The mechanical and electrical specifications of the Programmable Limit Switch are listed in Table 7.1.