Specifications

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Technical Description Section 10-2
10.1 General Information
The operating terminals allow for a simple connection to every Mitsubishi PLC of
the An / AnA series.
The operating terminal is connected to the communications module AJ71C24.
The software components of the system are fully adapted to the parameters and
marginal conditions of the interface.
This offers the user the following advantages:
- Random write and read access to any data within the PLC. Data of existing PLC
programs can be displayed and modified directly in the operating terminal. It is
not necessary to adapt the PLC program to the operating terminal in any respect
since it is not required that communications data be stored in a specified ad-
dress area or data type area.
- The operating terminal automatically polls the freely definable data areas for
cyclic data.
- No configuration is required in the PLC.
- The protocol is handled entirely by the operating system of the communications
module. A PLC program in the PLC is not required for the handling of the com-
munication.
- The protocol provides error control. Transmission errors are detected and, if
possible, eliminated by repeating the transmission. A noise-immune interface
hardware in accordance with the RS485 standard permits the application even
in a harsh industrial environment.
- The interface parameters are stored in the application description. Modifying of
the parameters is possible in the setup mask or in each other I/O mask of the
terminal at any time.
- The programming system provides a maximum of support to the operator in
programming the operating terminal. The definitions (abbreviations) used here
are identical with the definitions used within the PLC program (e.g. M3 cor-
responds to flag 3).
10.2 Technical Description
The interfacing of the operating terminal to the Mitsubishi A - PLC is effected by
means of the protocol type ”Protocol 1” of the communications module.
This allows random read and write access to all PLC data. Any bit-operands can be
accessed in bit-mode or word mode. The size of the address area depends on the
respective PLC.