Technical data

Introduction
8 VIPA GmbH CP486 ⋅ 4/94
Linkage with PLC:
This chapter describes detailed how to proceed with the linkage between PLC and CP486, that is
from the PLC point of view as well as from CP486 point of view.
1.2 Application Area
CP486 application within an automation system can be extended to many areas. Feasible application
areas are visualisation, measured value processing, production data acquisition, network servicing
up to the process control system and management computer. Hereto are added the most different
scope of duties with trade-specific standard software. Only the following aspects are important for
using the CP486:
- direct hardware linkage to the back plane bus via a standard CP interface with eight banks
enables a very fast communication with the PLC.
- linkage between PLC and CP486 is assisted by a system software supporting MS-DOS
programmers without STEP5 experience as well as STEP5 programmers without MS-DOS
experience (STEP5 from Siemens).
- CP486 is an PC-AT486 compatible computer.
- The enormous MS-DOS software world is made accessible for the PLC. Software packages are
directly applicable.
1.3 Structure and Operation
- Dualport-RAM:
The AT is directly interfaced to the back plane bus via a Dual Port RAM. This Dual Port RAM is
available on the PLC as standard CP interface with 8 banks. Data can be interchanged via
handling modules which also transfer synchronous to cycles the complete image of inputs,
outputs, markers, timers and counters to the AT. For every cycle you can exchange 4x127
variables in different directions. Communication is realized by polling or interrupt controlled.
- Communication Software
For communication between AT and PLC there are handling modules available providing the
data interchange element-oriented. Thus, several data elements (bit, byte, word, doubleword,
block) can be transferred per cycle at the same time. There is a continuously updated software
reference list for the standard software whose driver is adapted and loadable to CP486.