Project Description:
The "Spray and Tape" Machine Upgrade involved the
replacement of an existing relay-and-timer based control
system with a Programmable Logic Controller (PLC), including
the creation
and integration of a new control program.
The "Spray
and Tape" Machine, as it existed, utilized
outdated technology, being neither maintainable nor enhanceable
for the manufacture of abrasive products. In addition to
replacing the relay and timer-based control system with a
PLC, emphasis
was placed on orderly construction, standard practices, and
documentation for maintenance. A comprehensive, detailed
specification and sequence of operation was developed for
the new control
system.
Approach:
The switch-over to the new control system was done incrementally,
bringing photocells, switches, and solenoids over to the
new system individually while maintaining the old control.
For
example, an existing photocell was wired to the PLC, and
the PLC then provided the input signal to the old control
system.
Run time was affected for only small periods, and switchover
errors were easily located, minimizing their effect. When
all I/O were transferred to the PLC, the new control
program was
written and the old control hardware was removed.
Results:
The resulting evolutionary transition of the "Spray and
Tape" control system allowed the customer to maintain
productivity during this transition from old to new. During
this period there were only brief outages, something which
is of significant importance to most manufacturers. |
