Features; I I I Control Operations In Data Communications - Mitsubishi Electric AJ71C24-S6 User Manual

1. GENERAL DESCRIPTION
MELSEC-A
1.1 Features
The features of the AJ71 C24-S6 computer link module (hereafter called the
AJ71C24 in this manual) are given below.
1.1.1
Control operations in data communications
Data transmission operations between an AJ71C24 and external devices (e.
g., computers) can be controlled using either the dedicated protocols ( * I )
or in the no-protocol/bidirectional mode. These control operations can be
selected individually with the RS-232C and RS-422 ports of an AJ71C24.
(1) Communications using the dedicated protocols
(a) Communications at the request of the computer
Data communications is always initiated by the computer.
Designated data is transmitted according to the request command
transmitted from a computer to an AJ71C24.
It is not necessary to create and change special sequence
programs in order to use an AJ71 C24.
1) Read and write possible to and from all PC CPU devices
Data can be read from all PC CPU devices. This permits obser-
vation and monitoring of all operations, as well as the collection
and analysis of data. Data can be written to all PC CPU devices.
This permits production control and production directives to be
carried out.
2) An AJ71 C24 can upload and download programs from a PC CPU.
PC CPU programs (main sequence and subsequence control
programs and microcomputer programs), parameter data and
comment data are read by the computer and stored. When
required they can be written to the PC CPU to change the
program.
3) Remote RUN and STOP control of the PC CPU
The PC CPU can be remote-controlled by means of RUN and
STOP instructions from the computer.
4) When multiple computers and PC CPU modules are connected
to a link with an AJ71C24 module, the input (X) signals of the
CPUs in the link can be turned ONIOFF using any computer in
the link. This function can immediately stop or simultaneously
start all CPUs in the link.
(This function is called the global function of the AJ71C24.)
(b) Communications at the request of the PC CPU
The PC CPU transmits the data send request.
When the emergency data needs to be transmitted from a PC CPU
t o a computer, the PC CPU transmits a send request to the AJ71 C24
to make the computer execute an interrupt processing.