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5 PRELIMINARY INFORMATION
5.7 Reading and writing the buffer memory (using the transmission/reception buffer)
The method for reading and writing the R2 buffer memory using the
transmission/reception buffer is described below.
When the transmission/reception buffer is used, the required size only can be
adequately transmitted so excess data is not transmitted.
This allows the transmission path efficiency to be improved.
5.7.1 Outline
When reading and writing the R2 buffer memory using the transmission/reception
buffer, reading and writing are carried out using the intelligent device station access
request signal (RY(n+1)E) and the intelligent device station access complete signal
(RX(n+1)E).
The master station buffer memory uses the transmission/reception buffer.
TO(RIWT,RISEND)
FROM(RIRD,RIRCV)
1) 2)
3)4)
Programmable controller CPU Master station
R2 (1st station)
Buffer memory
Reception area
2nd station transmission/
reception area
Buffer memory
(Transmission/reception area)
Transmission area
...
1st station transmission/reception area
(1) Data (control data + transmission data) is stored in the master station
transmission area.
(2) When the intelligent device station access request signal (RY(n+1)E) turns ON,
the data stored in the transmission area is stored in the R2.
(3) When the intelligent device station access complete signal (RX(n+1)E) turns ON,
the response is stored in the master station reception area.
(4) The data is read from the master station reception area.
POINT
When the dedicated commands RIWT/RIRD/RISEND/RIRCV are used, the
intelligent device station access request signal (RY(n+1)E) and intelligent device
station access complete signal (RX(n+1)E) are controlled by the dedicated
commands, so the user does not need to establish an interlock.