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3. SPECIFICATIONS
MELSEC-A
3.3.2
Functions available
in
the no-protocol mode
3.3.3
Functions available in the bidirectional mode
3.3.4
Transmission error data read function
The above functions are as described in the respective corresponding
sections of the AJ71C2448 User's Manual.
3.4
Mode Switching Function During Computer Link Operations
Read this section carefully prior to switching the mode (changing the
transmission control protocol) in the middle of computer link operations to
continue data communications with a connected device. It is unnecessary
to consult with this section unless the mode must be switched.
Switching can be made between the following two modes from an external
device or PC CPU.
Dedicated protocol
One d formato ham l to4
'The
mode that can be switched from an external device
(Switching from the no-potocol mode to the dedicated protocol mode is
impossible.)
The mode switching functions are as follows:
I
Switchina Requesting Method
I
Mode
Switching
Function
Switching from
Switching from
External Device
I
PCCPY
Communication
Status When
Requesting
Switching
Switching Procedure
Normal
mode
switching
For writing to buffer memory address 119H, see Section 7.6.
Forced
mode
switching
When data
communications
is being
executed
When data
communications
not executed
When
data
is being
executed
When
data
communications
is not executed
The forced mode switching function switches the mode, irrespective of
the data communications status. It, therefore, is useful to avoid commu-
nication errors and resume communications.
The mode is switched after completing data
communications.
The mode is switched as soon as mode
switching is requested.
4
The on-going data communications is forced
to terminate as soon as mode switching is
requested, and the mode is switched.
The mode is switched as soon as mode
switching is requested.
Writing to buffer
address 119H
Writing
to buffer
memory address
119H
(forced mode switching request
+
designated mode)
Writing to buffer
memory address
119H (designated
mode)
mode
The mode
switching request
flag (Y(n+1)9) is
writing.
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