Technical data

Linkage with PLC
CP 486 ⋅ 00/14 VIPA GmbH 109
6.3 PLC-Jobs for CP486 (Functions for Bank 0 and 1)
6.3.1 Overview
All PLC-jobs are transacted via banks 0 and 1. In this way the CPU can use series of MS-DOS-
functions.
Die PLC-instructions are processed in background via interrupts, as soon as this driver is being
installed. In this way no additional software for the CP486 is necessary to operate the PLC-jobs.
The driver permits to call several MS-DOS system functions from the PC. Hereby all parameters
and information are exchanged transparent between PC and MS-DOS. The AT-driver software is
solely useful, to record the passed parameters correctly in the processor-register and to transfer the
returned values in a suitable form to the PC. The only fundamental restriction is, that only one part
of the MS-DOS system functions can be called by the PC. It´s not recommendable to call all
functions by the PC, because a great number of functions cannot be used meaningful by the PLC at
all. For further reasons a breakdown of the operating system can occur if a series of functions is
used in a non-adequate way. Therefore the driver software only supports such functions, which can
be used meaningful by the PLC. As function numbers for calling, exactly these function numbers of
the MS-DOS system function are to be specified.