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1. GENERAL DESCRIPTION
MELSEC-A
The AJ71C24-S6 has the following newly-added functions:
*Commands dedicated for use with the A2ACPU(Sl) and A3ACPU:
All memory devices of the A2ACPU(S1) and A3ACPU (the AnACPU in this
(
manual) are accessible using these dedicated commands.
Data transmission in the bidirectional mode:
This feature allows the AJ71C2436 to interface 1:l data communications
using the ACK code between a PC CPU and a computer.
When data is transmitted from the AJ71C24-S6 to a computer, a control
code ENQ, the data length code, and a check sum are added respectively
to the beginning, the middle, and the end of the send message. (The
check sum is optional.)
When the AJ71 C24-S6 receives data from a computer, it transmits a control
code ACKINAK back to the computer. This indicates the result of the
receive (normal/abnormal).
The AJ71C24-S6 thus adds the ENQ code, data length, and check sum
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and checks the reception of the response message at the data transmis-
sion. It checks the received data and sends the response message after
it received data.
The length of a data communications sequence program can be shortened
by using the bidirectional mode.
*The communications mode using the US-232C interface can be set to
either full-duplex or half-duplex:
The communications mode using the US-232C interface of the AJ71 C24-S6
can be switched either to full-duplex or half-duplex according to the
specifications of the peripheral device.
*Multidrop link with more than one computer is possible:
More than one computer can be put into a multidrop link with the AJ71 C24-
S6.
The PC CPU modules in the multidrop link can be accessed from the
computers for readlwrite of device data and sequence programs.
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If any existing programs are used with the AJ71C2446, see Appendix 1.2for interchangeability
between the AJ71C24-Sf5 and the following devices.
AJ71C24 computer link modules
AJ71C24-S3 computer link modules
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