SHEET
5
10
DF022-4PE-S1
2
1
3
4
F
E
D
C
B
A
F
E
D
C
B
A
2
1
3
4
DWG.
No.
c)
Data transmitted by master (control abort process)
1) Master sends ENQ code to slave.
2) Since ACK code cannot be sent, slave sent NAK code to master.
3) Sequence is repeated 3 times in attempts to retransmit. After receiving the 3
rd
successive NAK code, comms control is aborted.
Master
Slave
ENQ code (05H)
1)
NAK code (15H)
2)
3)
ENQ code (05H)
NAK code (15H)
ENQ code (05H)
NAK code (15H)
ENQ code (05H)
NAK code (15H)
RS
RS
RS
RS----232C
232C
232C
232C
conversion circuit
conversion circuit
conversion circuit
conversion circuit