LIM-2 Logic Inspection Module

A Flow Control Application
Using the LIM-2 Logic Inspection Module
The Application
Parts are processed through a heat
tunnel on a continuous motion
conveyor. Opposed mode photoelectric
sensors are placed at the
entrance and exit of the heat tunnel to
monitor part flow. An LIM-2 and an
LSR-64 shift register module process
the information from the sensors
and activate an alarm if a part does
not emerge from the tunnel when it
should. The length of the parts and
the spacing between adjacent parts
may be random.
Application Concept
The System
A narrow beam is established near
both the entrance and the exit of the
heat tunnel using SM30 Series sensors
with rectangular aperture assemblies
on the emitter and the receiver. The
Bi-Modal receiver outputs are wired
for dark operate and sinking (NPN)
operation.
When the beam of the entrance sensors
is blocked, data is input to the LSR-64
shift register. The length of the part
corresponds to the number of clock
pulses entered during the time that
the entrance beam is blocked. Clock
pulses are generated using an ECONO-
BEAM SE61E/SE61R combination as
a slot sensor to count pulses produced
by a timing sprocket attached to one
of the conveyor drive shafts.
The LSR-64 is programmed to output
when the part is clocked to the exit of
the tunnel. This information becomes
the gate input for the LIM-2. The exit
sensors supply a DATA signal to the
LIM-2 when the beam is blocked by
an exiting part. The exit sensors must
“see” the leading edge of an exiting part
at any time during the gate period in
order to prevent an alarm.
Hookup Diagram
Timing Diagram (assumes shift length of 5)
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