18 DATA COMMUNICATIONS BETWEEN TARGET DEVICE AND CPU MODULE IN M:N BASIS
18.3 Examples of Procedure for Data Communications with CPU Module
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18
The master station transmits a permission response to the slave station that issued the communications request.
The slave station that received the permission response performs the processing from after communicating data with
the CPU module within the maximum data communication time arranged among the target devices.
The master station that transmitted the permission response and the slave stations that does not obtain line ownership
check the line usage time of the slave station that obtained the line ownership, and ignore the received data not addressed to
their own station.
If the line usage time exceeds the maximum communication time, each target device performs the processing .
The slave station that has communicated data with the CPU module transmits a communication complete report to the
master station after data communications completed. A message structure example is shown in .
Slave stations that do not communicate data with the CPU module check if a communications complete report was
transmitted, and do not communicate data with the master station during that time.
(1B) (1C) (ZX) (CB)(2)(;)
(1B)
31H 42H
(1C)
31H 43H
(:)
31H 42H 31H 43H 5AH 58H 43H 42H32H3BH
3AH
(Y)
59H
*1
*1
Massage of Ò
Command "ZX" is a communications
request command for description purpose.
The user should select the command that
requests communications.
Massage wait
Transmission
destination
station No.
Transmission
source
station No.
Command
Sum check
code
Target device of
slave station that
wants to obtain the
line ownership
(1CH)
Permission granted/
permission not granted
Transmission
destination
station No.
Transmission
source
station No.
Master
station
target device
(1BH)
Massage of Ó
CPU
CPU CPU CPU
C24C24C24C24
Õ ÕÕ
×ÖÔ
Master
station
(Before
×
)
(After
×
)
Target device Target device Target device
(Station No.:1BH) (Station No.:1CH) (Station No.:1DH) (Station No.:1EH)
(Station No.:0H)
Target device
(Station No.:15H)
(Station No.:2H)
(Station No.:1H)
Target device that obtained the line ownership
The above C24 includes Q series C24, L series C24, QC24(N), and UC24.
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