However, this lack of
standardization generated a wide
variety of incompatibilities in
communication due to the
existence of a tidal wave of physical
systems and protocols
incompatible with each other.
It was in the 80s when there was an
attempt to standardize
communications with the MAP
(Manufacturing Automation
Protocol) protocol of General
Motor’s. It was also possible to
reduce the dimensions of the PLCs
and started programming with
symbolic programming through
personal computers instead of the
classic programming terminals.
The 1990s showed a gradual
reduction in the number of new
protocols and in the modernization
of the physical layers of the most
popular protocols that managed to
survive the 1980s. The latest
standard, IEC 1131-3, tries to unify
the programming system of all PLCs
in a single
international standard. Today we
have PLCs that can be programmed
in block diagrams, instruction lists
or even structured text at the same
time. However, computers began
to replace the PLC in some
applications and even the company
that introduced the Modicon 084
has changed its control based on a
PC.