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13 CONTENTS AND REGISTRATION OF USER FRAMES FOR DATA COMMUNICATION
13.2 Transmission/Reception Processing Using User Frame Registration Data
■Remarks
With the multidrop connection, including data for the target device to identify which station transmitted a message in the user
frame can facilitate creation of arbitrary data to be transmitted.
Receiving data
When user frame reception is designated
When the start frame is set, C24 receives the message when it receives data with the same arrangement as the designated
start frame.
If the final frame is set, C24 issues the read request of received data to the CPU module when it receives data with the same
arrangement as the designated final frame.
C24 reception processing by registration data
■Registered portion of 1-byte data for code of registration data, 01H to FEH
C24 receives and checks if the received data is data of the same code (01H to FEH) as the registered code.
When data code 03H, 0DH, 0AH is registered as user frame number, 3E8H
When user frame No. 3E8H is set for data reception, C24 receives and checks data codes 03H, 0DH, 0AH (ETX, CR, LF) as
the receive data of that user frame portion.
CPU C24
(0)
CPU C24
(1)
CPU C24
(5)
;;
1A
;
ABC 1 2 3
;
;
0
A
;
1A
;
5
A
;
S
T
X
S
T
X
S
T
X
S
T
X
L
F
C
R
L
F
C
R
L
F
C
R
L
F
C
R
“ABC123
Target device
Data used by the target device to identify the transmitting station
When message transmitted from the station No.1 C24
… Data designated to the station
No.1 C24 transmission data
designation area.
Arbitrary data
User frame
( ): Station No.
Data when transmitting
a frame written to each
C24 for transmission
B
42H41H 31H 32H
A12
34H 12H 03H 0AH0DH
34
33H 34H
(89ABH)
ABH 89H
(1234H)
E
T
X
C
R
L
F
4241H
89ABH
Arbitrary data
CPU module
C24
Buffer memory
When the C24 receives the
data,it issues reception data
read request to the CPU module
(Receive data
storage area)
Reception data
read request
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