3. Instruction Set
Program Example: COM2 (RS-485)
Communication between PLC and VFD-B series AC motor drives (ASCII Mode, M1143 = OFF).
Retry when communication time-out occurs.
M1002
MOV H86 D1120
SET M1120
MOV
K100
D1129
RST
M1127
M1127
X0
RSTEF
K1 K0
SET
M1122
M1129
X0
Processing received data
Receiving completed
Communication instruction setting:
Device address: 1 K0:
Reserved
S e t u p
communication protocol as
9600, 7, E, 1
Retain communication protocol
Set up communication time-out: 100ms
Sending request
Reset M1127.
PLC VFD, PLC sends: “:01 06 2002 0002 D5 ”
VFD PLC, PLC sends: “:01 06 2002 0002 D5 ”
Data to be sent (sending messages):
AC drive address : ADR (1,0)
Command code: CMD (1,0)
Data address
Data contents
Error checksum: LRC CHK (0,1)