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8 OTHER FUNCTIONS
8
8. OTHER FUNCTIONS
R2 and functions (special functions) other than data communication with an external
device are explained in this section.
8.1 Canceling data communication to an external device
After the transmission request signal (RYn0) has been turned ON, if the transmission
cancel request signal (RYn1) is turned ON before the transmission normal/error
complete signal (RXn0/RXn1) turns ON, the transmission to the external device will be
canceled.
When this function is executed, the transmission error complete signal (RXn1) will turn
ON.
The outline of this function is explained using the buffer memory automatic update
function.
(1) Flow of process
R2
RS-232-C
Master station
Bit device
Word device
Remote
input (RX)
Remote
output (RY)
Remote
output (RY)
Remote
input (RX)
Programmable controller CPU External
device
2) Transmission request ON
5) Transmission cancel
request ON
1) Transmission data write
Automatic
update
buffer
Trans-
mission
area
7) Transmission error
complete ON
6) Transmission cancel
3) Automatic read
4) Data transmission
9) Transmission error
complete OFF
Reception
8)
Transmission request OFF
Transmission cancel
request OFF
(2) Timing chart
1)
2)
3)
9)
5)
7)
8)
4)
6)
R2
Programmable
controller CPU
Master station Automatic update area
(transmission area)
Carried out with sequence program
Carried out by R2
External device
Transmission area
Transmission request
signal (RYn0)
Transmission cancel
request signal (RYn1)
Transmission error
complete signal (RXn1)
Transmission data
Transmission
Word device